Effectiveness of Teletherapy in Managing Voice Disorders: A Systematic Review

Abstract

Telerehabilitation has developed as one of the important aspects of health care delivery in the current era. Hence the present study aimed to systematically review the literature and understand the effectiveness of teletherapy in the management of voice disorders. A comprehensive search was performed in the PUBMED, CINAHL, and Scopus databases using Boolean operators, adhering to the PRISMA. The methodological quality of the selected studies was assessed using the ROBINS-I tool. The review included 12 articles meeting the inclusion criteria, featuring various study designs. All studies reported positive outcomes from televoice therapy intervention across multiple voice outcome measures, irrespective of whether participants received direct or indirect or a combination of voice therapy techniques. Studies comparing teletherapy with face-to-face therapy indicated that teletherapy is as effective as in-person therapy. However, the overall risk of bias assessment for the included studies, using the ROBINS-I tool, ranged from moderate to serious. This systematic review revealed that teletherapy is a feasible alternative to in-person therapy for voice disorders. However, there is a need to understand the effectiveness of teletherapy in demonstrating different voice therapy techniques. Further studies are needed to understand the application of various/particular voice therapy techniques via telepractice.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12070-025-05775-z.

Introduction

The human voice plays a significant role in each person’s life, serving as a unique identifier [1]. Therefore, dysphonia, or abnormal voice quality, can have a negative impact on an individual’s social, personal, and professional spheres [2]. Research indicates that behavioral voice therapy has been effective in improving the voice quality of those with dysphonia [3]. Voice therapy is considered the optimal and primary treatment for dysphonia. Given the behavioral nature of voice therapy, the active participation of the patient is crucial in determining the treatment plan and prognosis [4]. The majority of voice therapy sessions are intensive and in-person, often lasting longer than three sessions per week. This presents a challenge for both the patient and the clinician in achieving full recovery from voice problems [5]. Studies have shown that participants often face challenges in engaging in voice health education and training due to factors such as financial burdens, personal issues, difficulty taking time off from work, and challenges related to traveling to the therapy center. These barriers can exacerbate voice issues, prolong treatment, and worsen vocal problems [6–8].

Over the past seven years, telepractice has gained significant importance in overcoming the barriers faced in traditional face-to-face interventions within speech-language pathology. Telerehabilitation refers to the delivery of intervention services through telecommunication and internet technology, encompassing assessment, monitoring, prevention, intervention, supervision, education, counselling, and communication services directly supporting individuals with disabilities [9, 10]. As healthcare delivery continues to evolve and the demand for accessible and cost-effective services increases, teletherapy has emerged as a viable solution. ASHA endorses teletherapy as an appropriate and effective tool for speech-language pathologists (SLPs) to deliver services.

After 2020, the COVID-19 pandemic accelerated the adoption of teletherapy, resulting in a rise in research studies aimed at evaluating its efficacy, including the management of voice disorders [11]. Telepractice offers numerous advantages, including convenience, greater accessibility for patients, and the ability for providers to reach larger groups of clients regardless of geographical constraints. Studies have shown that telepractice for voice disorders achieves comparable levels of patient satisfaction to traditional face-to-face interventions, making it a widely accepted method in the field of voice disorder management [12–14]. A recent systematic review of five RCTs involving 233 patients with voice disorders [15] reported that voice therapy delivered through telerehabilitation is as effective as face-to-face voice therapy. While RCTs are considered the gold standard for clinical research, their strict protocols and controlled settings often limit the generalizability of their findings to real-world clinical practice. In contrast, non-randomized studies, which frequently involve more diverse populations and naturalistic interventions, offer critical insights into the effectiveness of interventions in everyday settings. Hence, the present systematic review expanded its scope by including randomized and non-randomized studies to understand a more holistic evaluation of the effectiveness of telerehabilitation in the management of voice disorders, accounting for a wider range of patient outcomes, settings, and treatment protocols.

Method

The current systematic review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines [16]. The protocol of this systematic review was registered with the Prospective Register of Systematic Reviews (Reg No: CRD42023390346).

Inclusion and Exclusion Criteria

Population

This review included individuals aged 16 years and older of both genders diagnosed with functional or organic voice disorders (such as muscle tension dysphonia, behavioral, hyper, or hypokinetic dysphonia, and nodules or polyps). Individuals who received teletherapy for speech and language disorders other than voice disorders, studies examining televoice therapy in healthy subjects, and those involving participants with dysphonia resulting from neurogenic conditions or head and neck cancer were excluded.

Intervention

Studies reporting the use of any form of synchronous (real-time online) or asynchronous (recorded videos) telerehabilitation methods were included.

Comparator

This review included both studies that compared traditional face-to-face voice therapy with teletherapy as well as studies that exclusively examined the effectiveness of teletherapy (pre- and post-teletherapy) without face-to-face comparisons.

Outcome

The review included all the measures related to acoustic, aerodynamic, auditory-perceptual, self-perceived voice assessments, and patient satisfaction.

Study Designs

Regardless of study design, all studies published in the English language between January 2000 and June 2024 were included.

Information Source and Search Strategy

A comprehensive data search was performed using electronic databases such as PubMed, CINAHL, and Scopus. The search was conducted to cover studies published from January 2000 to June 2024. The search strategy was first applied in PUBMED and subsequently replicated across other relevant databases. Furthermore, cross-references were searched to identify any missing studies. A detailed list of search terms was generated to develop a sensitive search strategy with keywords such as “voice disorders,” “voice problem,” “dysphonia,” “telehealth,” “voice therapy”, “tele practice”, and “telerehabilitation”. The keywords were combined with Boolean operators to create the search strings (Appendix A).

Data Collection and Management

Articles retrieved from electronic databases were compiled using the Rayyan QCRI platform [17]. After removing duplicates, two authors (M.V. & U.D.) independently screened the title, abstract, and full-text articles on the basis of the predefined inclusion and exclusion criteria. Any discrepancies were resolved with the involvement of a third reviewer (S.N.) until consensus was achieved.

M.V. and U.D. conducted a comprehensive examination of the included studies, extracting relevant data according to the predefined PICOS framework. The extracted data included study details (study title, author, and year), population characteristics (age, sex), data characteristics (aim, primary and secondary objectives, assessment tools used, outcome measures used), statistical methods used for analysis, and intervention strategies (comparison group, platform of intervention, devices used, duration and type of intervention). The data obtained were compared, the errors were corrected, and any disagreements present were resolved by discussion or consultation with a third reviewer (S.N.).

Risk of Bias Assessment

The risk of bias in the included studies was assessed independently by two reviewers, U.D. and S.N., using the Risk of Bias in Nonrandomized Studies of Interventions (ROBINS-I) tool [18]. The ROBINS-I evaluates potential sources of bias in three domains: pre-intervention (confounding and selection of participants), intervention (classifications of intervention), and post-intervention (deviations from intended intervention, missing data, measurement of outcomes, and selective reporting). On the basis of the evaluation of these domains, each study was rated as having a low, moderate, serious, or critical risk of bias, depending on the judgment of bias at each stage. Any discrepancies between the reviewers were resolved through discussion.

Results

Study Selection

The search resulted in the identification of a total of 5833 articles (1080 articles in PubMed, 3974 articles in Scopus, and 779 articles in CINAHL). After removing duplicate articles, 4481 studies were left for further review. Among these, 4408 articles were excluded after screening their titles and abstracts. From the remaining 73 studies, 61 were removed after a full-length review. Finally, 12 studies were included for qualitative synthesis. The detailed process is outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) chart (see Fig. 1).

Fig. 1.

The PRISMA flowchart of the process undertaken to select relevant studies for the current review

Study Characteristics

The studies included in the review were conducted in different geographical locations: the USA − 4 [11, 14, 19, 20], Italy 2 [13, 21], China-1 [22], South Korea-1 [23], Taiwan − 1 [24], South America– 1 [25], and Thailand– 1 [26], Australia − 1 [12]. A wide degree of variability was observed across the 12 studies in terms of study design (Table 1). Among the 12 studies selected for review, five were randomized controlled trials [11, 19, 23–25]. One was a non-randomized experimental study [22]. Four utilized a pretest-posttest single group design [12, 13, 20, 26], and two were observational studies [14, 21].

Table 1.

Included studies and their main findings

No	Author and year	Country	Study design	Study type	Aim	Main findings
1	Rangarathnam et al.[11]	USA	RCT	Prospective	To investigate the utility of telepractice for delivering flow phonation exercises to persons with Primary Muscle tension Dysphonia	The study found that airflow phonation exercises are equally effective for patients with MTD in both face-to-face and telepractice sessions.
2	Liu et al. [22]	China	Quasi-experimental design	Prospective	To explore the effectiveness of teletherapy in female elementary school teachers with self-reported voice disorders	Telepractice is an effective and feasible treatment for female elementary school teachers with voice problems and can reach a larger community.
3	Mashima et al. [19]	USA	RCT	Prospective	To perform voice therapy in-house through real time video monitoring system and to compare outcomes to conventionally treated patients.	Telepractice delivered through real-time video monitoring is found to be effective in individuals with voice disorders.
4	Kim, et al.[14]	California (USA)	Observational study design	retrospective	To compare patient and provider satisfaction with telepractice voice therapy during the COVID-19 pandemic and identify correlations with patient demographics.	Both patients and providers reported high satisfaction levels with telemedicine, especially when patients had reliable internet access.
5	Guzman et al. [25]	South America	RCT	Prospective	Assess the effectiveness of remote voice therapy (telepractice) with Acapella Choice device in subjects with vocal fatigue.	The voice therapy using the Acapella Choice device via telepractice was effective in improving voice quality in patients with vocal fatigue.
6	Mari et al. [13]	Italia	Prospective observational	Prospective	Analyze the functional outcomes of patients who experienced permanent unilateral vocal fold paralysis (post-thyroidectomy) and underwent synchronous telerehabilitation.	Tele-rehabilitation (TR) is effective for improving the voice of patients with unilateral vocal fold paralysis (UVFP).
7	Kim et al.[23]	Korea	RCT	Prospective	Evaluate the effectiveness of mobile-based voice therapy (MBVT) in comparison to traditional treatment methods.	The study found that mobile-based voice therapy (MBVT) is as effective as PC-based therapy for voice recovery in patients with benign vocal fold lesions. MBVT offers cost and location flexibility, making it ideal for home-based training.
8	Smith et al. [20]	USA	cohort study	Retrospective	Investigate the feasibility, utilization, and effectiveness of teletherapy in a large single-institution cohort of patients with dysphonia.	The study demonstrated that teletherapy is an effective and adaptable treatment option for patients with dysphonia, regardless of age, location, or diagnosis.
9	Fu et al. [12]	Australia	Observational	Prospective	Investigate the feasibility and efficacy of telepractice in delivering intensive voice therapy to individuals with vocal fold nodules in their own homes or workplace	Telepractice is a feasible and potentially effective method for delivering intensive voice therapy to individuals with vocal fold nodules.
10	Franz et al. [21]	Italy	Observational	Retrospective	1) Investigate the clinical effectiveness of delivering speech therapy via telepractice to patients with dysphonia. 2) Determine whether telerehabilitation alone can be as effective as a combination of telerehabilitation and in-person therapy.	Telerehabilitation, both as a standalone treatment and in combination with in-person sessions, may be a valuable tool for patients with limited treatment adherence, even outside a pandemic context.
11	Jaroentonyakorn et al. [26]	Thailand	Nonrandomized and comparative interventional clinical trial.	Prospective	To determine the efficacy of a hybrid group tele practice program in voice therapy for primary school teachers	Hybrid group tele practice program in voice theapy is helpful for preventing voice disorders in primary school teachers
12	Lin et al.[24]	Taiwan	RCT (sealed envelope; block randomization)	Prospective	To examine the study hypothesis that voice therapy via telepractice is not inferior to conventional (face-to-face) treatment for the elderly with voice disorders	The study shows that the effectiveness of voice therapy using tele practice was not inferior to the face-to-face theapy in elderly population.

Risk of Bias of the Included Studies

The risk of bias was assessed for each included study using the ROBINS-I tool, which evaluates seven domains of bias (D1 to D7). These domains include bias due to confounding, bias in the selection of participants, classification of interventions, deviations from intended interventions, missing data, measurement of outcomes, and selection of the reported results. Each domain was rated as having a low, moderate, or serious risk of bias. The overall risk of bias assessment revealed that four studies [11, 23–25] were judged to have a moderate risk of bias, primarily due to minor concerns in confounding factors and inconsistent reporting of intervention details. Whereas the remaining eight studies [12–14, 19–22, 26] were rated as having a serious risk of bias, predominantly attributable to inadequate control of confounding, poor handling of missing data, and significant measurement biases. The judgments for risk of bias based on the ROBINS-I tool for each study are presented in Fig. 2.

Fig. 2.

Traffic light plots represent the results of the ROBINS-I tool for the included study outcomes

General Characteristics According To Population, Intervention, Comparison, and Outcome

Population

A total of 809 participants were included across all the studies. In all the studies, females (n = 515) outnumbered males (n = 272) (Table 2). However, one study [25] did not report the gender distribution of the participants. Six of the 12 studies focused on a specific group of voice disorders. These included individuals diagnosed with primary muscle tension dysphonia [11], teachers with self-reported voice problems [22, 26], subjects with vocal fatigue without organic lesions [25], individuals with post-thyroidectomy vocal fold paralysis [13], and individuals with vocal nodules [12]. The remaining six studies included individuals with heterogeneous (functional and organic) voice disorders [14, 19–21, 23, 24] (Table 2). This diagnostic variability across studies introduces complexity in interpreting the overall effectiveness of tele-voice therapy.

Table 2.

Participant characteristics

No	Author and year		Sample Size	Gender	Participants age (average/range)
1	Rangarathnam et al.[11]		14 (EG − 7, CG − 7) patients confirmed with primary muscle tension dysphonia	Female-11 Male − 3	39.5 (16 to 81 years)
2	Liu et al. [22]		35 (EG − 18, CG − 17) female elementary school teachers with self-reported voice disorders	Female − 35 Male − 0	Experimental Group − 38.67 ± 9.5. Control Group − 38.35 ± 8.42
3	Mashima et al. [19]		51 (EG − 23, CG − 28) patients with voice disorders referred to Speech pathology clinic	Female − 38 Male − 34	Mean age of 45 years
4	Kim, et al. [14]		226 diagnosis of dysphonia	Female- 134 Male − 90 Transgender- 1 Nonbinary- 1	48.1 (17.3) (18 years and older)
5	Guzman et al. [25]		30 (EG − 15, CG − 15) patients reporting vocal fatigue with no organic VF lesions	Not specified	20 to 55 years
6	Mari et al. [13]		40 post-thyroidectomy UVFP	Female- 34 Male-6	49.4 ± 13 (21–73 years)
7	Kim et al. [23]		45 (EG − 25, CG − 20) patients with benign vocal fold lesions	Female − 26 Male − 19	46.3 ± 10.5 (32–67 years)
8	Smith et al. [20]		234 referred to SLPs with a primary diagnosis of dysphonia	Female-163 Male − 71	51.6 ± 20 years
9	Fu et al. [12]		10 cases with vocal nodule	Female − 10 Male − 0	33.7 (19 to 49 years)
10	Franz et al. [21]		Retrospective analysis − 32 patients referred for voice therapy Combined group (face-to-face + teletherapy) − 20 Only teletherapy − 12	Female-22 Male − 10	Median age 50 (17 to 89 years)
11	Jaroentonyakorn et al. [26]		12 teachers with voice disorder	Female − 9 Male − 3	Age range from 20 to 60 years (5 participants, 20–30 years; 3 participants, 30–40 years; 2 participants 40–50 years; 2 participants 50–60 years)
12	Lin et al. [24]		80 (33 EG, 36 CG)	Female − 33 Male − 36	Experimental: 66 ± 5.9 (57–82) Control: 69 ± 6.9 (58–81)

EG experimental group; CG control group; UVFP unilateral vocal fold paralysis

Across ten out of twelve studies, the average age of the participants ranged between 31.7 and 69 years, and two studies did not report the average age of the participants [25, 26] (Table 2). Although the inclusion criterion of our review specified participants aged 17 to 60 years, few studies [11, 13, 14, 21, 23] included participants older than 60 years. Despite this deviation, these studies were included in our review because they provided relevant data for participants within our specified age range and offered significant insights into the effectiveness of tele-voice therapy for patients experiencing voice disorders. Similarly, this review initially aimed to exclude studies that analyzed the effectiveness of tele-voice therapy for voice disorders secondary to neurological conditions. However, one study [20] with a heterogeneous group, including such conditions, was still included. It was retained because it involved a substantial number of participants with other organic and functional voice disorders, providing valuable data relevant to the scope of our review.

Intervention

Table 3 summarizes the voice therapy interventions used across the included studies. Eleven out of twelve studies [11–13, 19–26] employed various combinations of direct and indirect voice therapy approaches, with the exception of one study, which did not mention the details of voice therapy [14] and reported only patient and provider satisfaction among those who received voice therapy in tele mode during the COVID-19 pandemic. Vocal hygiene education was a common component across almost all studies except for two [21, 23]. Most of the studies combined vocal hygiene education and physiologic voice therapy techniques, except for five studies that included a combination of vocal hygiene, facilitating, and physiologic voice therapy techniques [12, 13, 19, 20, 26]. To maintain adherence to tele-practice sessions and to monitor participants’ engagement in interventions, a few studies have provided home training programs in the form of written instructions/printed handouts [20, 22, 24] and WhatsApp messages [25]. There was notable variability observed in both the participants’ vocal pathologies and the voice therapy techniques employed across all the studies (Tables 2 and 3).

Table 3.

Details of voice therapy applied in each study

No	Author and year	Subjects	Voice Therapy techniques	Tele practice platform	Duration of intervention
1	Rangarathnam et al.[11]	Muscle tension Dysphonia	VHE - adapted protocol established (information on intake of appropriate fluids, controlled use of voice and control of reflux or allergies). Airflow exercises (20–25 min) include gargling (with and without voice), cup bubble blowing and stretch and flow phonation	Tandberg interactive audio video unit	Both EG and CG attended total 12 sessions for 6 weeks (2 sessions per week) - 1st session vocal hygiene eduction (10–15 min) - 11 sessions - airflow exercises (20–25 min) + discussion on success and problem with the practice of vocal hygiene
2	Liu et al. [22]	Primary school teachers with self-reported voice problem	VHE (before commencing voice therapy) - vocal use habits, lifestyle and vocal health awarness. RVT - relaxation exercises, abdominal breathing exercises, resonance training. Home practice - daily homework to practice for 10–15 min once on treatment days and twice daily on other days	TVM video conferencing services	Voice therapy - Both groups (EG & CG) received 8 sessions, 30 min duration, twice a week for 4 weeks.
3	Mashima et al. [19]	Individuals with voice disorders (31 vocal nodule, 29 edema, 9 unilateral VF palsy, 3 with voice hyperfunction but no laryngral pathology)	- VHE - Facilitating voice therapy techniques - focus, establishing a new pitch, yawn– sigh, glottal attack changes, open-mouth approach, pitch inflections, and chant talk (Boone, 1982; Boone & McFarlane, 2000) - Confidential voice therapy for individuals with vocal nodules (Colton & Casper, 1996) - VFE for Vocal fold palsy (Stemple, Glaze, & Gerdeman, 1995) - Behavioral, lifestyle, and diet management for laryngeal reflux	Teletherapy delivered through remote video teleconferencing. Platform not mentioned	Average no of sessions 5.7, mean duration of each sessions was 30 min, median length of time from enrolment to discharge was 9 weeks
4	Kim, et al.[14]	Adult patients with a Hyperfunctional or hypofunctional	Patient and provider satisfaction (voice therapy details not provided)	Not mentioned	> than one session of teletherapy
5	Guzman et al. [25]	Functional dysphonia (non-organic dysphonia)	Treatment group: Acapella Choice treatment + VHE Control group: Water Resistance therapy + VHE Both groups perform a sequence of nine phonatory tasks and vocal hygiene exercises, including sustained vowel-like sounds, vocal tract shape changes, glissandos, messa di voce, song and speech melodies, and intensity and pitch accents. Vocal hygiene practices include hydration habits, control of exogenous inflammation, and control of high vocal fold impact stress. Participants are required to complete the same phonatory tasks 6–8 times daily for 5–10 min each time as part of a home exercise program. Patient compliance is monitored through daily WhatsApp messages.	Not mentioned	Both groups received a total of 6 sessions, 2 sessions/week for 3 weeks. Duration of session 30 min - 3 min discussion about home practice and issues with practice - 24 min practice of exercises - 3 min instruction for home practice
6	Mari et al. [13]	Unilateral vocal fold paralysis post theyroid surgery - (Participants included total thyroidectomy 28/40, lobo-isthmectomy 5/40 (12.5%), hemithyroidectomy 4/40 (10%), parathyroidectomy 3/40 (7,5%))	VHE - adequate hydration, vocal diet and changes in lifestyle habits (such as avoiding sour food and fizzy drinks), ideal speaking environment (such as avoiding to speak in the presence of dust and/or smoke), voice use and speaking style avoiding shouting, screaming, throat clearing, speaking for a long duration Voice protocol included 3 steps; 1) Abdominal breathing support and control of utterance duration. 2) Vocal exercises to strengthen and coordinate the laryngeal muscles and to improve the interplay between airflow, vocal fold vibration and supraglottic structures. following techniques recommended to achive this; - Cough and phonation -VFE - Phonation with compression of chest with bending downward and arms folded -Maneuvers aganist resistence (pushing and lifting) -Laryngeal manipulation 3) Half-swallow boom, lip and tongue trills 4) Generalization of the acquired techniques	Skype (Videoconferencing Platform)	Mean number of sessions were 8 (min.7- max 10) twice a week for 30 min.
7	Kim et al. [23]	Benign vocal fold lesions	VFE Accent method Inhalation phonation SOVTE	Mobile based voice therapy (Not specified)	8 weeks, 40 min /day, 1 day/ week. Total 8 sessions
8	Smith et al. [20]	Individuals with various voice disorders(muscle tension dysphonia, benign vocal fold mucosal lesion, vocal fold motion impairment, laryngopharyngitis, presbyphonia, acute laryngeal injury, functional dysphonia, malignant vocal fold mucosal lesions)	SOVTE RVT VFE VHE Home practice exercises	Zoom	Mean (SD) teletherapy sessions attended − 4.2(3.0) delivered over mean(SD) time interval of 98 (91)days
9	Fu et al. [12]	Vocal fold nodule	VHE Relaxation VFE Lessac-Madsen Resonant Voice Therapy	Skype	Total 9 sessions, 3 sessions/week 1 session in person VH + tehnology requirement - in person 8 sessions - teletherapy Home practice − 15 min (twice) on non-treatment day 15 min (once) - treatment day
10	Franz et al. [21]	12 - functional dysphonia, 14 structural vocal fold disorders (nodules, sulcus, VF hemorrhages, post-surgical scars), 4 VF paralysis, and 2 PDs related to dysphonia	Proprioceptive-Elastic (PROEL) method (except 2 PD) 2 PD cases - LSVT	Google meet	PROEL − 10 sessions, 45 min (once or twice a week) LSVT − 4 sessions lasting 60 min per week for 4 weeks
11	Jaroentonyakorn et al. [26]	Primary school teachers with voice disorders	Hybrid telepractice program (5 practice sessions through You tube; 5 group sessions through zoom cloud meetings) Phase 1 - Introduction (basic of speech mechanisms) - VHE - Question and answer sessions Phase 2: five lessons Lesson 1: - Posture for voice therapy - Relaxation techniques (Step 1: stretching the muscles of back, neck, shoulders, and face. Step 2: relaxing the muscles of tongue, face, jaw, neck, shoulders, abdomen, and back.) - Basic breathing Lesson 2: - Diaphragmatic breathing - Warm-up and warm-down (lip trill, tongue trill, and gargling) Lesson 3:: - Chewing method (words, phrases, and sentences) - Yawn-sigh method (words, phrases, and sentences) - Reduced glottal attack (words, phrases, sentences, and passages) Lesson 4: - Chant talk (phrases and sentences) - Resonant voice therapy (words, phrases, sentences, and passages) Lesson 5: - Yoga voice (relaxation techniques, diaphragmatic breathing, vocal warm-up, resonant voice therapy, and vocal warm-down) - Vocal function exercises	LINE official program (Zoom and YouTube)	Total − 11 sessions Phase 1: 1-hour 30-minute lecture via Zoom cloud meetings Phase 2: 5 self practice (via Youtube for 30 min); 5 group practice (group practice via Zoom cloud meetings for 60 min) sessions (5 weeks) Total five lessons; 1 lesson/week (2 sessions/week)
12	Lin et al. [24]	Elderly individuals with voice disorders Vocal atrophy − 33 Nodules − 6 Polyps − 10 Unilatral vocal fold paralysis − 13 Muscle tension dysphonia − 7	Session 1: VHE + phonatory mechanism Session 2–4: SOVTE + VFE (and pushing exercises for UVFP) Session 5–8: RVT Home practice Reading a handout of vocal hygiene VFE: 4 times/day SOVTE: 2 times of 5–10 min practice/day VFE: 2 times/day SOVTE: 2 times of 5–10 min practice/day RVT: 2 times of 10 min practice/day	Social media app (Line; LINE corporation)	8 sessions [one session/week; 30 to 45 min each sessions] Home practice after each session (handouts all exercises) Self-filling sheet for homework completion and feedback

VHE -vocal hygiene education; RVT -resonant voice therapy; TVM - Tencent VooV Meeting, VFE- vocal function exercises; SOVTE- semi occluded vocal tract exercises; LSVT- Lee Silverman voice treatment; UVFP -unilateral vocal fold paralysis; EG- experimental group; CG- control group; Proprioceptive-Elastic (PROEL) method; PD -Parkinson’s Disease

The number of voice therapy sessions varied across studies, ranging from a minimum of 4 [20] sessions to a maximum of 12 sessions [11]. In most studies, the number of therapy sessions is predetermined to evaluate the effectiveness of teletherapy [11, 21–23, 25, 26]. However, in a few studies, the number of sessions was determined based on individual patient needs [13, 19, 20] (Table 3).

The frequency of sessions varied between one to three sessions per week (Table 3). The total duration of therapy varied between 3 and 10 weeks, depending on the frequency of sessions/week. Only one study, Smith et al. [20], reported an extended therapy duration of 98 days, with a mean of 4.2 sessions, indicating a lower frequency of sessions spread over a longer period. The duration of each therapy session varied between 30 min and 60 min across the studies (Table 3).

Inconsistent reporting was evident across the included studies, particularly regarding intervention protocols, details of voice therapy techniques, adherence monitoring, home practice routines, and detailed reporting of outcome measures. This lack of consistency complicated direct comparisons and interpretation of the effectiveness of teletherapy.

Comparison

Six out of twelve studies evaluated the effectiveness of teletherapy in comparison with traditional face-to-face therapy [11, 19, 22–25]. Among these, five studies were randomized control trials [11, 19, 23–25], and one used a quasi-experimental study design [22].

Five studies included a pre-posttest design to understand the effectiveness of televoice therapy [12, 13, 20, 21, 26], and one study investigated patient and provider satisfaction with voice therapy delivered via telepractice during the COVID-19 pandemic and reported correlations between levels of satisfaction and patient demographic factors [14].

Outcome

The studies reviewed employed multiple outcome measures to evaluate the effectiveness of tele-voice therapy, commonly integrating patient-reported outcomes, auditory-perceptual evaluations, acoustic and aerodynamic assessments (Table 4). The Voice Handicap Index (VHI) was the most frequently used patient-reported measure, appearing in 9 of 11 studies [11–13, 21–26]. Other patient-reported outcomes included the Patient Satisfaction Rating Scale [19], Voice Fatigue Index (VFI) [25], Vocal Tract Discomfort Scale [25], Post-TR Satisfaction Questionnaire [13], and Voice-Related Quality of Life (VRQOL) [20]. In contrast, Mashima et al. [19] reported that participants rated voice improvement on a 6-point scale (1 = not at all, 6 = maximally) and on a 5-point rating scale given by ASHA (1 = positive response and 5 = negative response). However, Kim et al. [14] measured only self-reported patient and provider satisfaction using a visual analog scale ranging from 0 (not at all satisfied to 100 (extremely satisfied) and two binary questions: (i) desire to choose telemedicine over in-person therapy in the future and (ii) their internet reliability.

Table 4.

Voice therapy assessment and results

No	Study	Assessment	Results
1	Rangarathnam et al.[11]	Participant perception (VHI) Auditory perceptual evaluation (CAPE-V) Acoustical evaluation (NHR, VTI Mean phonatory airflow– measured using MSP and CSP Rlaw (laryngeal airway resistant measure) - the ratio of peak air pressure/mean airflow during voicing	No significant differences were found between the groups in self-reported (p = 0.259), perceptual (p = 0.620), and acoustic parameters (NHR p = 0.209; VTI p = 0.836). However, mean airflow during MSP and CSP tasks improved in the telepractice group and decreased in the in-person group, though this difference was not significant (MSP p = 0.073; CSP p = 0.181). Following voice therapy both groups showed significant improvements in perceptual (p = 0.001), self-reported (p = 0.002) and aerodynamic measure CSP (p = 0.04) and MSP (0.034).Acoustic measures NHR (p = 0.055), VTI (p = 0.75), laryngeal airway resistant measure Rlaw (p = 0.311) demonstrated clinical improvement even though it did not reach statistical significance. Overall, the study concluded that telepractice is an effective management option for muscle tension dysphonia.
2	Liu et al. [22]	Participant perception (VHI Chinese version), Auditory perceptual evaluation (GRBAS), Acoustic evaluation (Jitter, Shimmer, and HNR, SCR, NEDR, VTC using MATLAB), Aerodynamic evaluation (MPT) Home Practice: After each treatment session, the subjects were assigned with daily homework to practice. They were required to practice 10–15 min once daily on treatment days and twice daily on other days.	VHI - For EG group post-treatment total score of VHI-10 and three domain scores reduced, out of which total score (p = 0.0158) and emotional domain score (p = 0.0187) were statistically significant compared with pre-treatment scores. CG- VHI total score and all domain scores reduced significantly during the post-therapy evaluation (total score p = 0.0137, Functional score p = 0.0703, physical score p = 0.0105, emotional p = 0.0404). EG Vs. CG - Covariance analysis showed VHI-10 total score (p = 0.0137), physical domain (p = 0.0105), and emotional domain score (p = 0.0404) in EG were significantly lower than CG post-treatment and no significant difference in functional domain score (p = 0.0703) between groups. GRBAS - The EG showed a decrease in all GRBAS components after the intervention, with only the overall grade of dysphonia (G) being statistically significant (0.004). In the CG, both the overall grade of dysphonia (G) (p = 0.004) and voice roughness (R) (p = 0.031) significantly improved, but the overall improvement in GRBAS scores was not statistically different between the two groups. Acoustic parameters - Jitter and shimmer reduced in both groups (EG & CG) post-treatment but not statistically significant. MPT, HNR, increased in both groups and MPT was significantly higher in EG (p = 0.0001) and CG (p = 0.0203) post treatment with no significant difference in these parameters between group. SCR increased significantly (EG, p < 0.0001; CG, p < 0.0001), and NEDR decreased significantly (EG, p = 0.0021; CG, p = 0.0118) post-treatment with no significant difference between groups. A significant difference in VTC was observed in both EG and CG groups with no significant difference between groups post-treatment.
3	Mashima et al. [19]	Auditory perceptual - Blinded SLPs were presented with pairs of pre- and post-treatment voice samples to identify and rate the better voice sample. Patient satisfaction rating - participants rated voice improvement using 6 point scale (1 = not at all, 6 = maximally), and 10 statement voice therapy process and outcomes using 5 point rating scale given by ASHA (1 = positive response and 5 = negative response). Acoustic parameters - jitter and shimmer Fibro-optic laryngoscopy- to assess the physiological effects of voice therapy.	Auditory perceptual - SLPs rated post treatment samples better than pre-treatment for 90% of the participants and was statistically significant (p < 0.000). No significant difference between group (conventional and VTC therapy) (p < 0.394) and different etiology (p < 0.111). The overall mean for both groups was 5.24, indicating both groups felt their voice improved with therapy. Patient satisfaction ratings - participants in both groups perceived their voice improved after treatment with no significant difference between conventional and remote VTC group (p < 0.354). The overall mean ratings on the 10 statements ranged from 1.00 to 1.68, indicating a positive response to services provided and outcome of therapy. Participants in both groups were equally satisfied with therapy. Acoustic analysis - no significant difference in jitter (p = 0.390) and shimmer scores (p = 0.260) between groups post treatment and significant improvement from pre- to posttreatment jitter (p < 0.001) and shimmer ((p < 0.001) scores in both groups. Fibro-optic laryngoscopic evaluation - Posttreatment rated as better for 82% of participants with statistically significant difference(p < 0.000). No significant differences in laryngeal ratings between pre- and posttreatment across groups (conventional vs. remote VTC) (p < 0.331) or etiologies (p < 0.068).
4	Kim, et al. [14]	1. Self-reported patient and provider satisfaction survey on a VAS ranging from 0 (not at all satisfied to 100 (extremely satisfied). 2. TSQ; rated between 1 to 5 (patients) 3. Two binary questions (i) desire to choose telemedicine over in-person therapy in future (ii) their internet reliability	Provider satisfaction was rated by three speech-language pathologists for all patients and 55/226 patients (24.3%) completed a satisfaction survey. Most patients were diagnosed with hyperfunctional voice disorders. Mean VAS satisfaction scores (0-100) were high for patients 86.8 (SD = 18.6) and providers at 80.6 (SD = 19.7). The mean TSQ score was 4.4 (SD = 0.6) on a scale of 1–5. The correlation between TSQ and VAS patient satisfaction scores was strongly positive (r = 0.82). Whereas, the correlations between provider and patient satisfaction scores were weakly positive (r = 0.19 for VAS and r = 0.11 for TSQ). Provider satisfaction was significantly higher for hyperfunctional voice disorders compared to other disorders (D=-7.5, 95% CI: [-14.4 to -0.5]). Patients who had reliable internet were significantly more likely to prefer telemedicine for future visits (OR = 6.9), and Asian patients were also more likely to choose telemedicine compared to White patients (b = 0.4).
5	Guzman et al. [25]	Spanish-VFI Spanish VHI-30 Spanish-VTDS Home practice: Participants were instructed to complete phonatory tasks 6–8 times daily for 5–10 min per session, with detailed instructions provided on a paper sheet after each session. Daily compliance reminders were sent via WhatsApp.	VFI 1 and VFI 2 significantly decreased for Acapella and WRT (p < 0.001) post therapy. Whereas, VFI 3 showed significant change in only WRT group (p = 0.02). Significant reduction (p = 0.002) of VHI scores for both Acapella and WRT post therapy with no significant differences between groups. Significant reduction (P < 0.001) in VTDS score for both Acapella and WRT groups post therapy with no significant differences between groups.
6	Mari et al. [13]	Strobovideolaryngoscopy - glottal closure (complete or incomplete) Aerodynamic - MPT Acoustic parameters - Mean F0, jitter %, shimmaer %, NHR, VTI, DSH, frequency range (VRP) Auditory perceptual - GRBAS Participant perception - VHI, TSQ	Glottal closure - Before treatment, 13.3% of subjects had complete glottal closure, while 86.7% had glottal incompetence. Post-treatment, the prevalence of complete glottal closure significantly improved to 66.7% (p = 0.03), while lateral compression of the false vocal folds decreased from 67% pre-treatment to 33% post-treatment (p = 0.06). MPT - a significant improvement (p = 0.02) was found between pre-TR and late post-TR scores (mean pre-TR = 6.83 s, mean late post-TR = 10.33 s) Participant perception - a significant improvement (p = 0.04) was found between pre-TR and late post-TR scores of VHI. 87% were satisfied and preferred telerehabilitation over face-to-face. 80% rated video quality adequate and 20% rated excellent. GRBAS– significant improvement between pre and late post TR for G (p = 0.01), B (p = 0.01), A (p = 0.02) Acoustic parameters - Mean F0, Jitter %, Shimmer %, NHR, VTI, and DSH values decreased but not significantly (P > 0.05) at the early and post-TR. VRP analysis showed a nearly significant difference between pre- and post-TR (P = 0.06). TSQ- All subjects were satisfied. 87% liked the treatment, preferring it to the face to face. 80% judged audio and video quality adequate and 20% rated excellent.
7	Kim et al. [23]	Participant satisfaction - VHI-10 Auditory perceptual evalaution - GRBAS, CAPE-V Acoustic parameters– CPP, CPPS, AVQI version 2 (AVQIv2) and 3 (AVQIv3), and ABI.	MBVT & TRVT showed statistically significant changes in all variables (p < 0.01). The measured values of CPP and CPPS increased, while AVQI, ABI, Grade, overall severity (CAPE-V), and VHI-10 values decreased, confirming an improvement in voice quality in both MBVT and TRVT. Between MBVT and TRVT - pre-treatment no differences in the outcome measures (0.092 < p < 0.846). Post-treatment, significant differences were found in ABI (p = 0.013) and Grade (p = 0.021), with lower scores in the MBVT group indicating greater voice recovery compared to the TRVT group.
8	Smith et al. [20]	Participant perception - VRQOL Perceptual evalaution - GRBAS Aerodynamic - MPT, S/Z ratio Home practice: patients were provided with educational materials and instructions to practice at home between teletherapy sessions	V-RQOL– average score 62.9 before teletherapy (161 patients). After therapy, there was a significant improvement in scores (p < 0.001) for 48 patients who attended four or more sessions. GRBAS– before therapy, the GRBAS mean score was 1.7 for 57.7% of patients, and after therapy (for those who attended four or more sessions), the mean score improved to 1.2 with significant improvement (p < 0.001). Aerodynamic- limited changes in mean MPT scores in pre- and post-teletherapy (mean [SD]) 12.0 [6.4] and 13.2 [5.1], respectively. Statistically significant (p = 0.03) but clinically negligible decrease in mean [SD] scores for S/Z ratio (1.3 [0.4] and 0.8 [0.2]) following tele voice therapy.
9	Fu et al. [12]	Participant perception - PSQ and Chinese version of VHI. Auditory perceptual voice evalaution - GRBAS. Acoustic voice parameters - F0, jitter %, shimmer %, and NHR. Physiological assessment - MPT, MFR, subglottic pressure. Laryngoscopic evaluation - stroboscopy	PSQ: pre to post-therapy significant improvement in 11 out of 16 questions of PSQ. VHI– pre to post-therapy significant improvement in VHI total score (p = 0.028). On individual subscales, VHI-P scores showed significant improvement (p = 0.005), whereas VHI-F (P = 0.312) and VHI-E (P = 0.385) showed no significant differences post-treatment. Auditory perceptual voice evaluation - Significant improvement in grade (P < 0.001), roughness (P < 0.001) and asthenia (P < 0.005) post-treatment. Individual assessment showed better overall voice quality and roughness, and no change in breathiness. Acoustic parameters - significant increase in mean F0 (P < 0.001), and significant reductions were shown in jitter (P = 0.011), shimmer (P = 0.005), and NHR (P = 0.010) post-treatment. Physiological assessment - Significant changes in MFR (P = 0.036) and no changes in MPT (P = 0.513) and Subglottal pressure (P = 0.347) post-treatment. Laryngoscopic evaluation - Significant improvements across group from baseline to post treatment for ratings of mucosal wave (P = 0.035), vocal edge smoothness (P = 0.046) and glottal closure (P = 0.014). No significant change was found for symmetry of vocal fold abduction (P = 0.83), amplitude of vocal fold movement (P = 0.206), and regularity of vocal fold movement (P = 0.480)
10	Franz et al. [21]	Participant perception - VHI-10, Patient self-assessment of vocal fatigue. Auditory Perceptual voice evaluation - GIRBAS. Acoustical parameters - F0, jitter, shimmer, VRP Aerodynamic- MPT Videostroboscopy - supraglottic tone (presence and characteristics of supraglottic hypertonia/squeeze), phonatory vibration site, vocal fold morphology, vocal fold motility, vocal fold level, symmetry, periodicity and amplitude of vocal fold vibration, glottic closure, vocal fold edge smoothness, mucosal wave characteristics and vibratory interruptions.	VHI-10 - both groups significant improvement (p = 0.002) post-therapy. Self-assessment score - the median phonatory fatigue self-assessment scores for phonatory fatigue and voice quality were significantly higher than 0 (median score 2; range 0–2; p < 0.001) in both the combined therapy and telerehabilitation-only groups. Auditory perceptual evaluation - significant reduction in G (p = 0.001), R(p = 0.012), B (p = < 0.001) and S (p = < 0.001)post-therapy whereas, A (P = 1.000) and instability (p = 1.000) did not differ post-therapy in both groups. Acoustic parameters - F0 did not differ in both groups, whereas jitter (p = 0.003)and shimmer (p = < 0.001) decreased significantly in both groups. Aerodynamic - MPT increased significantly in both group (P = < 0.001). Videostroboscopy - significant improvement in VDS profile post-treatment in both group (Vocal fold thickening, p = 0.039, Supraglottic hyperfunction, p = 0.301, incomplete glottic closure, p = 0.137).
11	Jaroentonyakorn et al. [26]	Participant perception -VHI - Thai Acoustical evaluation (fundamental frequency, jitter, shimmer, HNR) Aerodynamic - MPT	VHI scores: all VHI domain scores decreased post-therapy and significantly differed for only emotional domain (VHI-E; P = 0.03). Acoustic analysis: significant difference post therapy for all parameters except F0 MPT significantly improved from 6.77 to 9.88 (0.008) The mean pre- and post-T-VHI total scores were 30.83 (median 27.00, min 16, max 67) and 24.02 (median 23.00, min 2, max 60)
12	Lin et al. [24]	Participant perception - VHI-10 Auditory Perceptual - GRBAS Aerodynamic evaluation - MPT Acoustical parameters - Jitter %, shimmer dB and NHR, CPPs Videolaryngostroboscopy (VLS) - Mucosal wave (0 as normal, 1 mildly decreased, 2 severely decreased and 3 absent) and glottic closure	Comparison between pre and post therapy - Significant improvement were observed in VHI-10, MPT, auditory perceptual evaluation and acoustic voice parameters in both groups Post therapy - No significant differences in the values of MPT, GRBAS, jitter, shimmer, NHR, and CPP between the experimental (teletherapy) and control (conventional therapy) groups. VLS: Mucosal wave: telepractice group, 11 patients had mildly decreased mucosal waves, and 6 returned to normal, while in the conventional group, 10 had mildly decreased mucosal waves, and 5 returned to normal. Glottal gap: both the telepractice and conventional groups exhibited a significantly decreased normalized glottal gap area after voice therapy, indicating improved glottic closure.

VHI voice handicap index; CAPE-V consensus auditory perceptual evaluation of voice; NHR noise-to-harmonic ration; VTI voice turbulence index; MSP maximum sustained phonation; CSP comfortable sustained phonation; GRBAS G-grade, R-roughness, B-breathiness, A-asthenia, S-strain; HNR harmonic-to-noise ratio; SCR spectral convergence ratio; NEDR nonlinear energy difference; VTC voice type component; MPT maximum phonation time; S-VFI Spanish vocal fatigue index; S-VTDS Spanish vocal tract discomfort scale; F0 fundamental frequency; DSH degree of sub-harmonic; VRP voice range profile; CPP cepstral peak prominence; CPPS cepstral peak prominence; AVQI acoustic voice quality index; ABI acoustic breathiness index; VRQOL voice-related quality of life; MAFR mean airflow rate; TSQ telemedicine satisfaction questionnaire; PSQ participant satisfaction questionnaire; VAS visual analog scale; WRT water resistance therapy; EG experimental group; CG control group; VTC video teleconference; TR telerehabilitation; MBVT mobile based voice therapy; TRVT traditional voice therapy; Rlaw laryngeal resistance; MATLAB Matrix Laboratory; ASHA American Speech and Hearing Association; SLP Speech-Language Pathologist; MFR Mean Airflow Rate; GIRBAS Grade, Instability Roughness Breathiness Asthenia Strain; VLS Videolaryngostroboscopy

For auditory-perceptual evaluations, the GRBAS/GIRBAS scale was used in 7 of 11 studies [12, 13, 20–24], whereas two studies included the Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V) [11, 23]. Mashima et al. [19] did not use a specific auditory perceptual scale. The authors blinded SLPs to the pairs of pre- and post-treatment voice samples to identify and rate better voice samples.

Acoustic parameters such as jitter, shimmer, and HNR/NHR were reported in 8 studies [11–13, 19, 21, 22, 24, 26]. Additional acoustic measures included fundamental frequency (F0) [12, 13, 21, 26], Voice Turbulence Index (VTI) [11, 13], Voice Range Profile (VRP) [13, 21], and various advanced acoustic measures, such as cepstral analysis, AVQI (versions 2 and 3), the ABI [23] convergence ratio (SCR), the nonlinear energy difference ratio (NEDR), and the voice type component (VTC) using MATLAB [22].

The maximum phonation time (MPT) was the most commonly used aerodynamic measure, appearing in 7 studies [12, 13, 20–22, 24, 26]. Other aerodynamic parameters included the mean phonatory airflow, laryngeal airway resistance [11], S/Z ratio [20], mean airflow rate, and subglottic pressure [12]. Additionally, five studies [12, 13, 19, 21, 24] employed fiberoptic laryngoscopy or videostroboscopy for visual-perceptual assessments pre- and post-therapy.

A review of the included studies on televoice therapy revealed significant improvements across various outcome measures, demonstrating the effectiveness of telepractice in voice therapy. Acoustic evaluations were included in seven studies, with common parameters such as fundamental frequency, jitter, shimmer, and the noise-to-harmonic ratio showing improvement post-intervention in all but one study [19]. Auditory-perceptual evaluations, which frequently use the GRBAS/GIRBAS scale, have shown significant improvements in parameters such as grade, roughness, and breathiness in multiple studies. Self-reported measures, including the Voice Handicap Index (VHI), Voice-Related Quality of Life (V-RQOL), and patient satisfaction questionnaires, also demonstrated substantial post-therapy improvements, particularly in studies that used VHI and VRQOL. Laryngeal imaging, which was used in four studies, indicated better glottal closure, smoother mucosal waves, and reduced nodule size post-intervention, supporting the visual perceptual outcomes of therapy. Aerodynamic measures, including Maximum Phonation Time (MPT), showed significant gains in four studies, with improvements in phonatory airflow and vocal efficiency. Collectively, these studies underscore the positive impact of tele-voice therapy across acoustic, perceptual, self-reported, laryngeal, and aerodynamic outcome measures, establishing it as a viable alternative to in-person therapy.

The assessment time points for recording the influence of telepractice varied across studies. Most studies conducted assessments immediately after the completion of the teletherapy sessions [12, 19, 20, 23]. Other studies have assessed outcomes for one-week post-therapy [22, 25] or both immediately and one month after the intervention [13]. Rangarathnam et al. [11] assessed it after five days of treatment, and Lin et al. [24] assessed it within two weeks of completion of teletherapy, whereas Franz et al. [21] assessed functional dysphonia immediately post-intervention and structural diseases one month after the intervention.

Among the 12 studies included in this review, 10 reported on the follow-up measures and their duration. The most commonly used follow-up time point was immediately after the intervention, as seen in several studies [12, 19, 23, 26]. One study reported follow-up assessment at six months [21], and a few other studies conducted follow-up assessments within 1 to 2 weeks post-intervention [22, 24, 25]. However, longer-term outcome data were largely absent across the included studies.

Discussion

Even though telemedicine/therapy was part of healthcare, it gained its significance during the COVID-19 pandemic when remote healthcare was the need of the hour. Hence, there has been a drastic increase in the number of studies conducted to measure the effectiveness of telemedicine/therapy during and after the pandemic to evaluate the effectiveness of this method of treatment in various conditions, including voice disorders. In support of this view, nine out of the twelve studies included in the present review explored the effectiveness of teletherapy during or after the COVID-19 pandemic. The surge in research following the pandemic reflects the growing interest among speech-language pathologists (SLPs) in teletherapy as an accessible and viable method of treatment. Hence, there exists a need to systematically analyze the results of these studies in terms of feasibility, accessibility, patient outcomes, and associated challenges. The outcome of these reviews plays an important role in evidence-based practices and the integration of teletherapy into routine care. Hence, the present study aimed to evaluate the effectiveness of teletherapy for voice disorders.

The present review analyzed 12 studies (RCTs and non-RCTs), including 809 patients with different voice disorders (functional and structural vocal pathologies). Studies in the review analyzed the effect of teletherapy compared with conventional voice therapy (face-to-face) or pre- and post-test comparisons of patients who underwent only teletherapy. The included studies assessed the effectiveness of teletherapy using a variety of outcome measures, such as auditory-perceptual evaluations, self-perception assessments, acoustic measurements, aerodynamic evaluations, and patient satisfaction levels. Despite the variations in study designs, patient populations, and teletherapy platforms across studies, teletherapy consistently demonstrated positive outcomes in the management of voice disorders.

The reviewed studies employed a combination of direct (e.g., facilitating, and physiological exercises) and indirect (e.g., relaxation exercises, vocal hygiene education, counseling) voice therapy techniques. The combination of these approaches addresses both the physiological and behavioral components of voice disorders, which are often multifactorial in nature. While teletherapy was found to be effective in using both direct and indirect techniques, there has been limited discussion regarding the effective delivery of these techniques through telepractice. Certain direct techniques, such as relaxation exercises and circumlaryngeal massage, are traditionally more effective in face-to-face settings, and it remains unclear how well these techniques translate to a teletherapy format. The wide variation in study populations and therapeutic techniques across studies makes it difficult to draw definitive conclusions about which specific techniques can be delivered most effectively through teletherapy. As such, this systematic review highlights the need for further research to better understand the efficacy of delivering particular voice therapy techniques via telepractice.

Furthermore, there was a lack of consistency in the number of voice therapy sessions conducted across the included studies. While the majority of studies reported a predetermined duration and number of therapy sessions, none provided evidence-based rationale for the selection of these session parameters except one study [11] that targeted 12 sessions of voice therapy on the basis of inputs from the literature [27]. Additionally, many of the studies failed to specify the inclusion of home practice routines or adherence to therapy schedules, leaving the long-term maintenance of therapeutic gains unaddressed. This gap in reporting highlights the need for further research to establish standardized guidelines for the duration and frequency of voice therapy sessions, as well as the role of home practice in maintaining treatment outcomes.

The broad range of outcome measures applied across the studies included in this review suggested that teletherapy is as effective as face-to-face therapy. Most of the studies have shown improvements in auditory perceptual evaluation using GRBAS or CAPE-V in terms of overall severity, breathiness, and asthenia post-therapy. Patient self-perceived measures (VHI, VRQOL, VOiSS, TSQ, etc.) significantly improved after therapy, with most studies reporting no significant difference between tele- and face-to-face therapy. However, few studies have reported better improvement with face-to-face therapy compared to teletherapy, suggesting that personal interaction in face-to-face therapy leads to better perceptions of benefits compared to teletherapy.

Furthermore, the majority of the studies reported positive outcomes following tele- and face-to-face therapy in terms of acoustic measures (jitter, shimmer, and noise-to-harmonic ratio (NHR)), aerodynamic measures (MPT, subglottic pressure), and laryngoscopic evaluations (glottic closure, mucosal wave). However, some studies reporting that there is no significant difference in shimmer following both tele- and face-to-face therapy suggest that not all objective voice parameters show significant differences following voice therapy irrespective of therapy modality. Similarly, aerodynamic and laryngoscopic measures demonstrated positive outcomes of teletherapy. Some studies that included laryngoscopic measures reported improved glottic closure and vocal fold function. Improvements in both objective (e.g., acoustic, aerodynamic, and laryngoscopic parameters) and subjective (e.g., self-reported and auditory perceptual evaluations) results strongly suggest that teletherapy can be considered an alternative to traditional methods of voice therapy.

While the overall findings of this review support teletherapy as an effective treatment option for voice disorders, several limitations remain in the current systematic review. The presence of moderate to serious bias in the majority of included studies highlights a critical limitation in the available evidence. Issues such as uncontrolled confounding, limited transparency in reporting methodologies, and incomplete outcome data significantly weaken confidence in the findings. Future research should prioritize study designs, clearer intervention protocols, improved participant selection strategies, and consistent reporting aligned with recommended guidelines to reduce bias and enhance the validity and applicability of the findings.

The small sample sizes observed in many of the included studies present another major limitation, diminishing the reliability and generalizability of the findings. Consequently, conclusions drawn from these studies may not be widely applicable to broader populations. Future research should focus on recruiting larger participant groups or conducting multi-center studies.

The broad range of diagnostic categories included across studies represents another important source of variability. While some studies focused on specific conditions such as Muscle Tension Dysphonia (MTD) and vocal fold paralysis, others included heterogeneous groups with both functional and organic voice disorders. The effectiveness of teletherapy may vary depending on the condition, yet this was not discussed in the reviewed articles. Future research should categorize participants based on diagnostic categories or conduct condition-specific therapy to determine the most appropriate use of tele-voice therapy for different clinical populations.

Another limitation identified in this systematic review was the substantial variability across the interventions employed by the included studies. Differences in therapeutic approaches (e.g., direct versus indirect methods and their combinations), number and frequency of sessions, session duration, and mode of delivery posed significant challenges for drawing robust conclusions. Such variability limits the generalizability of the current findings. Telepractice is limited in its ability to provide tactile cues and perform laryngeal manipulation, which are essential components in the management of specific voice disorders such as muscle tension dysphonia. Future research should prioritize the development and implementation of standardized teletherapy intervention protocols. Establishing clear guidelines, such as specifying appropriate techniques suitable for teletherapy-delivery, recommending session frequency and duration, and standardizing methods for facilitating and monitoring home practice, would greatly enhance comparability. Adhering to standardized intervention frameworks would ultimately allow for stronger evidence synthesis and clearer recommendations regarding tele-voice therapy.

Although many studies reported overall participant satisfaction with teletherapy, technological barriers were frequently reported such as poor internet connectivity, inadequate audio/video quality, limited access to appropriate digital devices, and varying levels of digital literacy among patients and clinicians. These factors could have impacted on the consistency, quality, and efficacy of teletherapy delivery; however, most studies failed to systematically evaluate or report the extent and influence of these barriers.

Another limitation across the reviewed studies was the lack of assessment of long-term outcomes. While the studies provided strong evidence supporting the immediate effectiveness of teletherapy interventions, very few assessed whether improvements were maintained in the long term. The absence of longitudinal follow-up severely restricts the understanding of the durability and clinical significance of the treatment gains achieved through teletherapy. Future research should prioritize long-term follow-up assessments, incorporating measures at multiple intervals post-intervention (e.g., 1, 3, and 6-month follow-ups). Such long-term evaluations are essential to determine whether therapeutic benefits persist and to understand the factors influencing the maintenance or regression of improvements.

Conclusion

Telerehabilitation is considered an alternative to face-to-face voice therapy, and it is found to be effective for various voice disorders. This systematic review included a wide range of participants and techniques used in telerehabilitation. Nevertheless, this study lacks details on the effectiveness of telerehabilitation on specific techniques, the number of sessions, and the lack of documentation on the home training program. Therefore, future studies should look for the comparison of tele and in-person therapy and the constraints of telerehabilitation, focus on the treatment protocol to magnify the efficacy of voice therapy, and focus on the advancements in the technology of telerehabilitation.

Electronic Supplementary Material

Below is the link to the electronic supplementary material.

Author Contributions

Authors contributions conceptualization: MV, SN, RR, UD, investigation: MV, UD; Formal analysis: MV, SN, UD; writing– original draft: MV, SN, UD; writing– review and editing: MV, SN, RR, UD. All authors reviewed the results and approved the final version of the manuscript.

Funding

No sponsorship or funding was provided for this research.

Declarations

Compliance with Ethical Standards

This article does not contain any studies with human participants or animals performed by any of the authors.

Informed Consent

Not applicable as the study did not include the involvement of human or animal participants.

Competing Interests

The authors declare that they have no competing interests.