Breathing pattern disorder: assessment and diagnosis

Abstract

Breathing pattern disorder (BrPD) is an important and common cause of breathlessness; however, the approach to assessment and diagnosis is variable. Consequently, identification of BrPD is inconsistent, risks clinical underestimation and diagnostic delays, and may lead to inappropriate treatments and patient distress. This review aimed to explore the measurement properties of assessment instruments available for BrPD and proposes evidence-based frameworks for identification, assessment and diagnosis.

A total of seven patient-reported outcomes and nine physical outcome measurements used in BrPD were identified, but validation in BrPD and evidence for clinometric properties was frequently not available. Comprehensive evaluation of BrPD requires assessment of both symptoms and breathing patterns, and we propose a framework for diagnosis of BrPD that includes three components: symptom screening using the Nijmegen questionnaire, physical assessment using the Breathing Pattern Assessment Tool, and excluding or optimising underlying conditions. A screening and assessment framework is proposed to facilitate a confident diagnosis of BrPD and underpin individualised treatment.

Shareable abstract

Various tools are available to assess and diagnose breathing pattern disorder. This review critically examines these tools, and proposes an evidence-based approach for comprehensive assessment and diagnosis of the condition. https://bit.ly/4rKt0M1

Introduction

Breathing pattern disorder (BrPD) is also known as dysfunctional breathing and is described as “breathlessness due to an abnormal breathing pattern that has no organic cause, or that is out of keeping with any organic disease present and/or level of exertion, and that has a significant impact on the individual” [1].

BrPD often presents with breathlessness; however, other nonrespiratory symptoms such as anxiety, dizziness, paraesthesia in the fingers, toes or around the mouth, and palpitations may also be present. BrPD can occur in the presence of, or absence of lung disease. It has an estimated prevalence of 10% in the general population [2], 30% in people with asthma [3, 4] and up to 64% in patients with difficult asthma [5]. In people with asthma, it is associated with worse asthma control and reduced health-related quality of life [6, 7], and is increasingly recognised as a modifiable comorbidity [8]. However, underappreciation of its importance and uncertainty around diagnostic criteria often results in under-diagnosis leaving the condition untreated.

The concept of BrPD has evolved over time. Historically, the term hyperventilation syndrome was used to define the condition over 80 years ago, and it was viewed predominantly as a psychological phenomenon, with links to anxiety and panic disorders [9]. It was thought that the psychological provocation of the sympathetic nervous system increased the release of adrenal hormones, producing hyperventilation and physical sensations like those experienced during “nervous attacks”. Consequently, the assessment of BrPD in individuals who had no underlying respiratory pathology was conducted using specific hyperventilation tests.

Advancing recognition and understanding of the condition later introduced the term “dysfunctional breathing”, which was proposed nearly 30 years ago [10]. This term described disordered respiratory function which encompassed sensory breathing awareness and abnormal musculoskeletal respiratory patterns, in addition to hyperventilation. BrPD started to move from the psychiatric domain and was increasingly linked to people with underlying respiratory conditions, predominantly asthma where it was thought to amplify symptoms. Despite new terminology and a more comprehensive understanding of BrPD, the diagnostic criteria remained centred on hyperventilation [4]. Nevertheless, growing recognition of abnormal breathing patterns, such as apical breathing and frequent sighing, contributed to the creation of assessment tools designed to objectively evaluate breathing mechanics [11–13].

Recently, both clinicians and consumers have reached consensus to adopt the term “breathing pattern disorder” [14]. This recommendation has been formally endorsed in position statements [15] noting that previous interchangeable use of terminology reduced the significance of the condition, leading to delays in diagnosis, treatment and advances in research.

In addition to differences in terminology, various frameworks have been suggested for classifying BrPD. In 2015, Barker and Everard [16] suggested categorising the condition into thoracic and extra-thoracic types, and acknowledged that the lack of objective assessment tools to quantify abnormal breathing patterns undermined recognition of the disorder. Boulding et al. [17] published a review of the literature and proposed the following classifications: hyperventilation, periodic deep sighing, thoracic dominant breathing, forced abdominal expiration and thoraco-abdominal asynchrony. Although five classifications were proposed, most studies reviewed focused solely on hyperventilation [17]. Courtney et al. [18] recommended a multidimensional approach with three proposed domains: biochemical (hyperventilation), biomechanical (breathing pattern abnormalities) and psychophysiological (emotional factors that affect breathing function). These different classification systems describe characteristics often seen in clinical practice, but they have yet to be validated.

Our understanding of this condition has evolved over time, from initially being labelled as hyperventilation to the broader term of breathing pattern disorder, now recognised in people with no psychiatric conditions and in those with underlying respiratory pathology. Advances have led to the development of classification systems [16–18] and new assessment tools, and a variety of interventions have shown positive effects [19]. Despite these developments there remains no gold standard diagnostic criteria, and no single assessment tool that comprehensively measures the signs and symptoms that characterise the condition. It remains under-recognised, with many clinicians unaware of the condition, or the appropriate screening and referral procedures for further assessment.

A recent systematic review, conducted in accordance with the COnsensus-based Standards for the selection of health Measurement Instruments (COSMIN), identified the Nijmegen questionnaire as the only measurement tool that met quality standards for clinical application in BrPD [20]. Consequently, this review will provide a narrative evaluation of the common assessment tools for BrPD and discuss diagnostic approaches and key assessment components that inform treatment selection. In addition, it will offer suggestions on recognising and screening the condition within clinical settings to facilitate timely referrals for further assessment.

Methods

A narrative review was conducted to evaluate the existing literature on assessment and diagnosis of BrPD. This approach was taken due to the wide-ranging nature of the subject and the limited standardised data available regarding relevant assessment tools. Electronic searches of databases (Cochrane Database of Systematic reviews; MEDLINE; Embase and CINAHL (Cumulative Index to Nursing and Allied Health Literature)) were undertaken using the following key terms: hyperventilation, over breathing, air hunger, breathing pattern and dysfunctional breathing. Reference lists of relevant studies were also searched. Measurement tools were included for review if they reported diagnostic thresholds or were commonly used for BrPD assessment in interventional research. Extracted information was grouped according to diagnostic thresholds, patient-reported outcomes and physical assessments. The results are presented thematically to illustrate the broad scope of assessments available and to provide clinicians and researchers with a framework that reflects the advancement of evidence in this area.

Assessment of breathing pattern disorder

BrPD can exist independently, or as a comorbidity with underlying respiratory disease where symptoms are disproportionate to usual objective testing. A comprehensive assessment including thorough subjective assessment, investigations to exclude or optimise any organic cause of breathlessness, patient-reported outcome measures (PROMs) and objective measures of breathing mechanics are critical to inform diagnosis and management. Physiological investigations including pulmonary function tests with maximal inspiratory and expiratory pressures, diaphragm screening and chest and/or cardiac imaging may be useful to exclude or optimise any underlying causes of breathlessness.

Subjective assessment

A thorough subjective evaluation of the patient's primary symptoms and medical history should be performed. People with BrPD may present with a variety of signs and symptoms. Although the predominant symptom is breathlessness, it may occur with chest tightness and/or pain, fatigue, anxiety, dizziness and paraesthesia. Frequently observed signs include air hunger (frequent sighing or yawning), rapid or erratic respiration, and upper chest and mouth breathing. Obtaining detailed descriptions from the patient regarding their symptoms and triggers can offer helpful insight into the characteristics and impact of the condition. Often patients have undergone numerous diagnostic evaluations and although negative results may reassure some, it may be frustrating for others when an explanation for their breathlessness or exercise intolerance remains elusive. Therefore, the subjective assessment should provide adequate time to explore these symptoms and their nature and provide validation of their impact. This approach is considered essential by clinicians for engaging patients in treatment interventions [14, 21].

Objective assessment

Various objective assessment tools are used to assess BrPD [14]; however, there is significant heterogeneity in the clinometric properties of these tools with many not validated specifically for BrPD and/or too complex to use in clinical practice [20]. Generally, a combination of assessments is used clinically to capture the variety of signs and symptoms that are characteristic of BrPD, and help guide treatment selection and evaluation.

Patient-reported outcome measures

In a survey of specialist physiotherapists, six different PROMs evaluating hyperventilation, breathlessness and psychological symptoms were suggested for inclusion in the assessment of BrPD [21]. Most PROMs have not been designed as diagnostic instruments for BrPD, nor have specific validation in BrPD, and none have established minimum important difference (MID) thresholds in this patient cohort. However, they are useful for screening the features and burden of different BrPD symptoms and can help guide treatment choice in this patient cohort. The characteristics of PROMs are presented in table 1.

TABLE 1.

Characteristics of patient-reported outcome measures used in breathing pattern disorder

Outcome measure	Population developed and validated	Context for use	Resources		Score range Higher score = worse symptoms	Diagnostic threshold for BrPD
			Cost and access	Time to complete
Nijmegen Questionnaire	Psychiatric and internal medicine Hyperventilation Asthma and COPD	Screen and measure hyperventilation symptoms	Free Translated into multiple languages https://www.physiotherapyforbpd.org.uk/Nijmegen-Questionnaire-2019.pdf	5 min	0–64	≥19 to ≥23
Self-evaluation of Breathing Questionnaire	Healthy adults who had concerns about their breathing	Measure BrPD symptoms	Free Translated into Danish and Turkish https://doi.org/10.1016/j.ijosm.2009.02.001	5–10 min	0–75	x
Dysponea-12	COPD ILD Heart failure	Measure physical and affective severity of breathlessness	Free Translated into multiple languages https://toolkit.severeasthma.org.au/wp-content/uploads/sites/2/2018/03/Dyspnoea12Questionnaire.pdf	<5 min	0–36	x
Breathe-VQ	General population	Measure “anxious” breathing	Free Translated into Danish https://doi.org/10.1183/13993003.00031-2023	<5 min	6–30	≥16.5
Hospital Anxiety and Depression Scale	General population Various chronic diseases	Screen and measure severity of anxiety and depression	Copyrighted Translated into multiple languages https://eprovide.mapi-trust.org/instruments/hospital-anxiety-and-depression-scale	5 min	0–21 each subscale	x
Patient Health Questionnaire	General population	Screen and measure for generalised depression severity	Copyrighted Translated into multiple languages https://eprovide.mapi-trust.org/instruments/patient-health-questionnaire	<5 min	0–27	x
Generalised Anxiety Disorder-7	General population	Screen and measure for generalised anxiety disorder	Copyrighted Translated into multiple languages https://eprovide.mapi-trust.org/instruments/generalized-anxiety-disorder-7	<5 min	0–21	x

BrPD: breathing pattern disorder; ILD: interstitial lung disease; Breathe-VQ: Breathing Vigilance Questionnaire.

Nijmegen questionnaire

The Nijmegen questionnaire (NQ) was developed over 40 years ago to screen for hyperventilation in people from psychiatric or internal medicine clinics who could benefit from breathing training [22, 23]. It was originally validated against the hyperventilation provocation test; however, further studies showed variable correlation with physiological hyperventilation and respiratory alkalosis [24]. It contains 16 symptoms associated with hyperventilation syndrome that are scored on a 5-point Likert scale resulting in a total score ranging from 0 to 64. The 16 symptoms were further categorised into three groups: shortness of breath, peripheral tetany and central tetany [25]. It continues to be commonly used in clinical practice, and the original authors have since preferred to describe the NQ score as a measure of “functional respiratory complaints” that relate to breathing, stress and anxiety rather than a measure of hyperventilation specifically [26]. Different diagnostic cut-off scores for BrPD have been applied ranging from ≥19 to ≥23 [19, 26]; however, the latter is commonly accepted as diagnostic for BrPD. In a recent systematic review, the NQ was the only assessment measure for BrPD that was graded as “high quality” [20]. It has been validated in people with hyperventilation [22, 25], asthma [27] and COPD [28], has been translated into several different languages [26], is quick to administer, and is widely used in research and clinical practice to assess and diagnose BrPD [19]. Limitations to the NQ remain. The original 16-item questionnaire does not fit structural validity requirements, and a proposed 15-item version provides more accuracy in representing symptoms of BrPD [29]. Correlation with physiological markers is inconsistent [24], and it does not assess breathing mechanics or predict who will respond to treatment. In people with asthma, breathing re-training improved quality of life in those with both high and low NQ scores [7, 30]. This suggests the NQ does not detect the range of symptoms characteristic of BrPD and is inadequate as a standalone diagnostic tool.

Self-Evaluation of Breathing Questionnaire

The Self-Evaluation of Breathing Questionnaire (SEBQ) is a 25-item tool that was developed to measure BrPD symptoms. The items in the SEBQ were selected based on respiratory symptoms associated with BrPD in the literature and clinical experience [31] and are scored on a 4-point Likert scale resulting in total score ranging from 0 to 75. The SEBQ evaluates two aspects of BrPD: air hunger and the perception of physically restricted breathing. Items relating to air hunger correlate with the NQ; however, items relating to the perception of restricted breathing do not. This suggests that the SEBQ is useful for identifying symptoms resulting from breathing mechanics [31]. It has been translated into Danish and Turkish [32, 33], has high test–retest reliability [34] and has shown responsiveness in small cohorts [35–37]. Although expert opinion suggests a cut-off score of ≥25 for diagnosis, this has not been verified [38]. While the SEBQ may capture aspects of breathing sensation and perceived biomechanical restriction not fully reflected in the NQ, current evidence in symptomatic populations remains limited, and its role is best considered complementary rather than diagnostic.

Dyspnoea-12

The Dyspnoea-12 (D-12) is not specific to BrPD but provides a comprehensive measure of breathlessness including physical and affective aspects [21, 39]. It contains 12 items that are rated on a 4-point Likert scale resulting in a total score ranging from 0 to 36 (physical subscore range 0–21, affective subscore 0–15). It has high test–retest reliability [39], has been validated in people with a range of chronic lung conditions [39–43] and has been translated into several different languages [44]. The D-12 has shown responsiveness in small studies in people with BrPD [45–47], but no MID has been established for this patient population.

Breathing Vigilance Questionnaire

Excessive self-monitoring of breathing may contribute to BrPD symptoms, and the Breathing Vigilance Questionnaire (Breathe-VQ) assesses this anxiety-induced, breathing-related hypervigilance [48]. The tool contains six items that are scored on a 5-point Likert scale resulting in a total score from 6 to 30. The Breath-VQ is reliable and was developed using a large sample from the general population. It was validated in a healthy population for BrPD using the NQ and has been translated into Danish [48, 49]. A cut-off score of ≥16.5 has moderate sensitivity of 0.72 and specificity of 0.68 for BrPD diagnosis [48]; however, it has only been investigated in one study; and further research is required prior to considering it for diagnostic use. Its responsiveness to interventions has not yet been established; however, it may be useful for guiding treatment choice and assessing changes in people who intensely self-monitor their breathing symptoms.

Psychological variables

Psychological factors can influence breathing regulation and symptoms. No specific assessment tool Exists to assess this in people with BrPD; however, specialist physiotherapists recommend screening patients using generic questionnaires such as the Hospital Anxiety and Depression Scale (HADS), the Patient Health Questionnaire (PHQ-9) or the Generalised Anxiety Disorder-7 (GAD-7) [21]. These questionnaires are quick to administer; however, they are not diagnostic and are used to identify patients who may benefit from further psychological assessment or support.

Physical assessments

Objective physical assessments for BrPD include those related to breathing patterns and hyperventilation both at rest and during exercise, and range from free tools to those that require costly equipment and training. Musculoskeletal assessments may also be performed to identify issues that contribute to abnormal breathing mechanics. Most tests have not been validated and no MID thresholds exist. The characteristics of different physical assessments are presented in table 2.

TABLE 2.

Characteristics of physical outcome measures used in breathing pattern disorder

Outcome measure	Population developed	Context for use	Resources		Can assess exercise-specific BrPD	Diagnostic threshold for BrPD
			Cost, access and training	Time to complete
Breathing Pattern Assessment Tool	Asthma and unexplained breathlessness	Screen for BrPD	Free https://www.physiotherapyforbpd.org.uk/BPAT.pdf	1 min	x	≥4
Hi Lo	Not specified	Assess upper and lower breathing contribution	Free	1 min	x	x
Manual Assessment of Respiratory Motion	Experienced breathers	Assess and measure breathing pattern	Free Specialist training required	5 min	x	x
Plethysmography	Respiratory	Measure lung volumes and breathing patterns	Equipment and software €€€ Specialist training and interpretation	30–60 min	✓	x
Hyperventilation Provocation Test	Panic and anxiety disorders	Screen for hyperventilation	Free	5–10 min	x	x
Capnography and transcutaneous CO2 monitoring	Emergency medicine Intensive care	Measure respiratory alkalosis	Equipment and analysis €€ Training required	5 min	✓	x
Breath hold assessment	Chronic disease	Assess CO2 tolerance	Free	5–10 min	x	x
Cardiopulmonary Exercise Test	Athletes Unexplained breathlessness	Assess ventilation changes with exercise	Equipment and software €€€ Specialist training and interpretation	>60 min	✓	x
Field walking tests	Cardiopulmonary	Assess exercise capacity	Free Training required	30–60 min	x	x

BrPD: breathing pattern disorder.

Breathing patterns

Common breathing pattern abnormalities present in BrPD include high respiratory rate, frequent sighing/yawning, throat clearing, irregular breathing patterns (rapid, erratic or noisy) and thoracic dominant breathing. Various tools can be used to objectively measure breathing mechanics including observation, manual assessment and the use of advanced technological equipment.

Breathing pattern assessment tool

The Breathing Pattern Assessment Tool (BPAT) was designed as a screening tool for BrPD in people with asthma and unexplained breathlessness [13]. It evaluates seven abnormal breathing characteristics that contribute to the condition: chest wall movement (apical versus abdominal), channels of respiration (oral versus nasal), noise of inspiratory and expiratory respiratory flow, signs of air hunger, respiratory rate and rhythm of breathing. Each item is scored from 0 to 2, resulting in a total range from 0 to 14. A BPAT score of ≥4 had a sensitivity of 0.92 and a specificity of 0.75 for detecting physiotherapist-diagnosed BrPD [13], and these test characteristics have been reproduced in people with long-COVID and postural orthostatic tachycardia syndrome [50, 51]. Higher BPAT scores have been associated with increased breathlessness and hyperventilation symptoms, reduced quality of life and exercise capacity, and worse asthma control [13, 52]. In people with asthma, the tool has excellent inter-rater reliability for in-person assessment between physiotherapists (intraclass correlation coefficient (ICC)=0.95, 95% CI 0.91–0.98) and good reliability when conducted by video assessment (ICC=0.76, 95% CI 0.56–0.88) [53]. The reduced reliability in video assessment is due primarily, but not exclusively, to reduced clarity of sound recordings, and exclusion of respiratory flow sounds improves reproducibility of video assessment [53]. It has also shown good reliability for remote assessment of people with COPD (ICC=0.70, 95% CI 0.47–0.86) [54]. The BPAT has shown responsiveness to treatment in some small studies [47, 55, 56]; however, the MID has not been determined.

Hi Lo breathing assessment

This test manually assesses one aspect of breathing mechanics: the relative movement of upper and lower rib cage compartments. The test is conducted by positioning one hand on the upper chest and the other on the abdomen [57]. The movement of each hand is observed and quantified as a percentage. Predominant upper chest movement may indicate BrPD. The Hi Lo is easy to learn and use [58], but the results of the test can vary depending on the clinician's subjective estimation and patient position. It has shown responsiveness in small case studies [37, 59]; however, it has not been validated, nor is it diagnostic.

Manual assessment of respiratory motion

The Manual Assessment of Respiratory Motion (MARM) is used to evaluate and quantify the distribution of breathing motion between the upper and lower parts of the rib cage and abdomen through palpation. The assessor sits behind the patient and places their hands on the posterior and lateral ribcage, with the thumbs parallel to the spine [12]. From this position, an assessment is made of breathing movement in the vertical and lateral planes, and it is charted on a pie chart. The MARM variables that are measured are overall area of breathing motion, the balance between the upper and lower parts of the rib cage, and per cent rib cage motion. It has good inter-rater reliability (ICC=0.75–0.98) [11, 12] and was validated in a group of “experienced breathers” using respiratory inductive plethysmography [12]. It can be conducted during different breathing postures, and a modified scoring system can be utilised where “0” represents balanced breathing to “3” representing maximal upper rib cage dominant movement [35]. The MARM has shown responsiveness to treatment in small cohorts [35, 36, 59, 60]; however, no MID has been established.

Plethysmography

Optoelectronic, structured light and respiratory inductive plethysmography are noninvasive measures of ribcage, chest wall and abdomen during breathing [61]. These tests provide physiological data that can confirm changes in breathing patterns at rest and during exertion; however, they require the individual to maintain positions which may influence breathing mechanics (e.g. arms held away from the chest) and are predominantly used in research with athletes [62–64]. These factors, alongside the high cost of complex equipment and difficult interpretation limit their clinical use.

Musculoskeletal assessments

Postural and structural abnormalities in the spine and rib cage can contribute to abnormal breathing mechanics. Musculoskeletal measurements of cervical and thoracic range of movement, myofascial trigger points and identification of musculature abnormalities are not validated but can assist with assessment and treatment selection [35, 65].

Hyperventilation

Despite growing awareness that BrPD is a complex and multidimensional disorder, hyperventilation syndrome continues to be the most frequently reported type of BrPD in the literature [17], and assessments that aim to objectively measure this are common both clinically and in research [19]. Hypocapnia is defined as an arterial blood partial pressure of carbon dioxide (CO₂) <35 mmHg [66]; however, symptoms have not been shown to correlate with CO₂ levels, so interpretation can be challenging and should not be diagnostic [67]. Additionally, interventions like breathing retraining can improve symptoms in people with hyperventilation syndrome without changing end-tidal CO₂ (ETCO₂) levels [68]. For these reasons, hyperventilation assessments should not be performed as diagnostic tests but may assist in guiding treatment choice.

Hyperventilation Provocation Test

This is a procedure where a patient voluntarily breathes rapidly for a few minutes to induce hypocapnia [9]. Measurements of ETCO₂ can be taken during the test, and if the symptoms produced by over-breathing replicate those experienced by the patient, then it is considered positive. Hyperventilation Provocation Test (HVPT) protocols were originally designed to characterise ETCO₂ recovery following a period of voluntary over-breathing alongside assessment of symptom recognition [69]. Although ETCO₂ recovery ratios at three and five minutes were proposed as objective markers, subsequent analyses demonstrated substantial overlap between patient and control groups with limited additional discriminatory value beyond symptom reporting alone [69]. Additionally, placebo-controlled isocapnic studies indicated that symptom reproduction during provocation was not specific to hypocapnia, and similar symptoms could be elicited despite stable ETCO₂ levels [70]. The HVPT was used diagnostically in early BrPD research [68, 71–80]; however, it is no longer frequently used or recommended due to its limited specificity [24].

Measurements of respiratory alkalosis

The usual method to analyse arterial CO₂ is direct arterial puncture, which can be painful and may be associated with other complications [81]. Less-invasive techniques include capnography which measures ETCO₂ or transcutaneous monitoring (TcCO₂) which uses a heated sensor that is applied to the skin [82]. These techniques provide variable accuracy of arterial CO₂ [82–84] and can be used during exercise [85]. Capnography is frequently employed as a biofeedback intervention for BrPD and has demonstrated sensitivity to treatment [19]. However, a range of diagnostic threshold measurements for ETCO₂ have been utilised [19], and the inconsistency between hypocapnia and clinical symptoms indicates that these tests should not be solely relied upon for diagnostic purposes.

Breath hold assessment

The ability to breath hold has been used as a clinical test to determine “fitness” in healthy people since 1900 [86]. The expiratory breath hold test for hyperventilation was developed by Dr Konstantin Buteyko who believed that hypocapnia was the cause of various symptoms and diseases [87]. He proposed that alveolar CO₂ could be estimated by breath holding time using his patented mathematical formula [88]. It was suggested, though not thoroughly tested, that a cut-off score of <30 s corresponded to mild BrPD and <20 s indicated severe BrPD. Further studies have revealed no correlation between breath hold times and ETCO₂ [89], or with exercise performance [90]. The breath hold test has shown responsiveness to treatment but should not be used diagnostically [91].

Cardiopulmonary Exercise Test

Cardiopulmonary Exercise Test (CPET) is a noninvasive assessment that measures breath-by-breath ventilatory, cardiovascular and metabolic responses during incremental exercise. Unlike resting investigations, CPET evaluates the dynamic physiological response to exertion and therefore has particular value in patients with disproportionate or unexplained breathlessness. Characteristic findings in BrPD may include an inappropriately high breathing frequency, erratic tidal volume–breathing frequency relationships, disproportionate ventilation relative to metabolic demand, elevated ventilatory equivalents and low ETCO₂ in the absence of gas exchange impairment. The interpretation of CPET parameters for BrPD remains subjective and is not yet diagnostic [92, 93]. More recently, nonlinear analyses such as approximate entropy have demonstrated that ventilatory irregularity can be objectively quantified, extending on visual pattern recognition and strengthening the physiological basis for diagnosis [93]. Protocols have helped improve recognition of BrPD in CPET, although there is still some inconsistency in how these are applied [94].

Field walking tests

The 6-min walk test and shuttle walk tests are common measures of exercise capacity in people with chronic lung disease [95]. In clinical settings, factors such as erratic breathing, changes in posture, oral or nasal breathing and the involvement of respiratory muscles are assessed during these tests; however, there is currently no objective measurement available to validate these observations. Field walking tests are not diagnostic for BrPD, but can be used to determine exercise capacity, inform treatment selection and assess the outcomes of interventions. They have shown responsiveness in small studies [65, 96, 97]; however, no MID exists for this patient population.

Diagnosis

Currently, there is no universally accepted diagnostic criterion for BrPD, and no single assessment tool that comprehensively evaluates the signs and symptoms characteristic of the condition. Inclusion criteria and diagnostic approaches in randomised controlled trials of BrPD treatments are inconsistent and have predominantly used measures of hyperventilation (HVPT, NQ, ETCO₂) which do not adequately reflect all types of BrPD and its complexity [19]. BrPD is a multidimensional condition characterised by interacting symptom burden, altered breathing sensations, observable breathing pattern abnormalities and variable physiological findings. Using one tool in isolation will not adequately capture the range of patient presentations in BrPD. Recent studies have combined various assessment tools for diagnosis and evidence suggests that different assessment methods may identify overlapping but distinct features of BrPD [7, 98, 99]. Symptom-based tools tend to reflect perceived breathlessness and associated affective responses, whereas observational assessments capture biomechanical breathing behaviours. Establishing formal diagnostic criteria and assessment protocols for the condition is essential to standardise research outcomes, guide clinical practice and improve patient outcomes. For these reasons, we recommend that diagnostic and assessment frameworks be supported by validated objective assessments that include both symptom screening and physical assessment.

Proposal for diagnostic evaluation

The proposed diagnosis framework for BrPD is presented in figure 1. Using this approach, we propose that a positive clinical diagnosis can be made using validated measurements for different types of BrPD and aligns with consensus from expert clinicians [14]. It contains the following key components: Symptom score of ≥23 on the NQ or a physical score of ≥4 on the BPAT, and signs and symptoms that are inconsistent and/or incongruent with physiological assessment. Assessment of only one BrPD component is insufficient for diagnosis. In cases where symptom scores are high in the absence of observable breathing pattern abnormalities, clinicians should evaluate alternative contributors to breathlessness.

FIGURE 1.

Components for diagnosis of breathing pattern disorder.

Symptom screening

Recurrent episodes of breathlessness or discomfort related to breathing that are characteristic of BrPD are screened using the NQ, and a score ≥23 is accepted as positive.

Physical assessment

Abnormal breathing patterns characteristic of BrPD at rest are identified using the BPAT, and a score of ≥4 is accepted as positive. Patients who report excessive symptoms with exercise should be considered for cardiopulmonary exercise testing.

Exclude or optimise underlying conditions

Symptoms or physical signs should be disproportionate or unexplained despite excluding or optimising underlying cardiorespiratory, neuromuscular and other comorbid conditions. If coexisting medical issues are present, the characteristic symptoms and objective breathing pattern abnormalities of BrPD should exceed what would typically be expected given the severity of these conditions. Failure to optimise underlying conditions risks misdiagnosis and reduced treatment efficacy.

Proposal for screening and standardised assessment

BrPD is no longer considered solely a diagnosis of exclusion. When screening for the condition, there are specific signs and symptoms that can assist clinicians in evaluating both the likelihood and potential impact of BrPD in a patient. These can assist in determining when specialist referral for assessment is needed. The fundamental elements of a comprehensive assessment for BrPD have been qualitatively identified by clinicians [14, 21], and interventions to treat the condition have been evaluated [19]. Aligning with this existing knowledge, we propose the following standardised screening and assessment procedure detailed in figure 2. This framework supports timely, accurate clinical diagnosis and enables the objective assessment of personalised treatment strategies for BrPD.

FIGURE 2.

Standardised screening and assessment procedure for breathing pattern disorder. BPAT: Breathing Pattern Assessment Tool; Breathe-VQ: Breathing Vigilance Questionnaire; MARM: Manual Assessment of Respiratory Motion.

Identification and screening

For referring clinicians, it is primarily valuable to involve a physician to evaluate previous test results and potential underlying conditions contributing to the patient's symptoms or review by a speech therapist or psychologist for upper airway or psychological concerns. There is a high probability of BrPD if a patient presents with signs and symptoms of air hunger (inability to take a deep breath and frequent yawning or sighing) or displays abnormal breathing mechanics such as upper chest, erratic, shallow or mouth breathing. These can be assessed using the NQ and BPAT, and a referral for a comprehensive, specialist assessment is indicated if there is moderate symptom severity or significant impact on the patient's functioning that is contributing to increased medication use and healthcare utilisation. Patients who report disproportionate symptoms with exercise should be considered for early evaluation with CPET.

Subjective assessment

This includes a comprehensive assessment of presenting complaints and contains a thorough report of the patient's symptoms and medical history (figure 2).

Objective assessment

Both the NQ and BPAT are required to objectively evaluate symptoms and breathing patterns and provide a formal diagnosis. Other relevant objective measures that address breathlessness, emotional functioning, musculoskeletal complaints and exercise may be utilised as indicated by findings from the subjective assessment. These assessments can support individualised treatment selection and evaluate the effects of interventions (figure 2).

Discussion

BrPD is an important condition with increasing relevance and recognition in patients with breathlessness. Our understanding of BrPD has evolved significantly over the years, and this review summarises the existing knowledge around assessment methodologies and provides a framework for identification, comprehensive assessment and diagnosis.

Diagnosis of BrPD should include both symptom evaluation and physical testing. Weak-to-moderate associations are reported between symptom-based and observational measures that suggest they measure related but nonidentical dimensions of BrPD. This combined approach mitigates the limitations inherent in each measurement tool when used in isolation. Currently, the Nijmegen questionnaire and the Breathing Pattern Assessment Tool are the only validated instruments available for diagnostic use [13, 26–28, 50, 51]. A structured approach like the one proposed will ensure that the diagnosis of BrPD is grounded in positive identification rather than exclusion alone, aligning with contemporary diagnostic frameworks used effectively in other conditions [100, 101]. A positive diagnostic framework supports accurate identification, validates legitimacy to both patients and clinicians, and provides appropriate management pathways. Moreover, a formal diagnosis standardises clinical and research documentation and promotes increased recognition of the condition.

A range of treatments have been used for people with BrPD in the literature, and breathing retraining appears to be beneficial [19]. However, the outcome measurements utilised are not consistently objective, and the quality of evidence supporting its effectiveness remains low. Using standardised assessment approaches that combine subjective questionnaires, observational methods and objective physical testing will ensure thorough patient evaluation, guide individualised effective treatment and strengthen the quality of evidence. The implementation of standardised assessment procedures for BrPD should be evaluated using a multisite approach to provide comprehensive benchmarking data, identify knowledge gaps and guide evidence-based decision making and resource allocation. This will support equitable and informed treatment selection across both clinical and research settings.

Exercise-related manifestations of BrPD may reflect distinct breathing behaviours that are insufficiently captured by resting assessments. Our understanding of BrPD during exercise has advanced through cardiopulmonary exercise testing and optoelectronic plethysmography [64, 92–94]; however, these methods are not easily accessible for many clinicians or patients, nor are they diagnostic. There is a need for the development and validation of simple, clinically applicable tools to assess BrPD during exertion, which should be prioritised in future research. This assessment could represent a modification of the BPAT, retaining its format while incorporating revisions to capture BrPD features commonly observed during exercise. This would not be a substitute for CPET; however, it may facilitate earlier identification of BrPD and enable more timely treatment options.

Conceptual frameworks are essential to ensure that outcome measures used in the assessment and diagnosis of BrPD address the critical features of this complex condition. The proposed frameworks for a positive diagnosis and screening presented here are aligned with the existing knowledge base and may change as evidence builds, although several limitations remain. No single instrument fully captures all the signs and symptoms of the condition, and available assessment tools show considerable heterogeneity in measurement properties with many lacking robust clinometric evidence. Few existing tools have been systematically evaluated against established frameworks such COSMIN [20] particularly for responsiveness, measurement error and minimal important differences. This limits the interpretability of treatment effects and comparability across studies. Future research should prioritise framework-informed evaluation of assessment tools in people with BrPD, focusing on validity, reliability, treatment responsiveness and the establishment of MIDs to improve standardisation and clinical utility.

Conclusions

The assessment and diagnosis of BrPD should utilise validated instruments that comprehensively identify the signs and symptoms of the condition, as well as evaluate appropriate treatment options. This review highlights the need for contemporary methods to screen, assess and diagnose BrPD, and offers new approaches for these processes. This is a critical step towards more effective treatments and improved outcomes for people living with BrPD.