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. Author manuscript; available in PMC: 2012 Oct 18.
Published in final edited form as: Semin Speech Lang. 2012 Jul 31;33(3):203–216. doi: 10.1055/s-0032-1320040

Table 2.

Published Studies of Long-term Effects of Surface Electrical Stimulation Using a Therapeutic Regime in Patient and Healthy Populations

Long-term results of e-stim following a therapeutic regime in patients
References Study Type Subjects/etiology Evaluation techniques Treatment groups Authors conclusion Outcome measures Follow-up post intervention
Bogaardt et al, 2009 retrospective case series 25 patients with Multiple sclerosis (MS) (mean age: 53.1±9.8yrs)

mean time since MS onset: 16.5±10.2 yrs		 17/25 patients had FEES

  1. Dysphagia Severity Scale

  2. Quality of life questionnaire

  3. Penetration –Aspiration Scale (VFS) (Rosenbek, Robbins et al. 1996)

  4. Residue in valleculae and pyriform sinuses

 EG: NMES at 30Hz, phase duration 200 μs, Placement 1 (Vital Stim®)

20 minutes for 6 sessions (2 sessions/week)

20 swallows; 60 swallows/session

  1. significant statistical improvement in Dysphagia Severity Scale p<0.01

  2. significant improvement in PA scores in EG for liquid (p<0.01)

  3. significant Change in pooling in pyriform sinuses post treatment. (p<0.01)

  4. significant change in quality of life swallowing score (p=0.01)

 Functional Physiological Immediate evaluation: 3 weeks post inclusion
Gallas et al, 2010 prospective case studies 11 dysphagic stroke patients (5 fem, 68 ± 11 yrs old > 8 weeks post stroke)

  1. VFS

  2. Mapping with Pharyngeal Motor Evoked Potentials (TMS measurements)

  3. Dysphagia Handicap Index (French)

 TES on submental area

5 sessions, 1h/day, 5s every minute, 80 Hz below motor threshold +Swallowing

  1. significant decrease of SRT for liquid and paste (p<0.05)

  2. significant reduction of residue and A/P scores (p<0.05)

  3. no change in TMS measurements

 Physiological Neurophysiological Quality of life Immediately 1 week later post-treatment
Lim et al, 2009 randomised controlled Trial 36 stroke patients

Inclusion criteria:

  1. confirmed stroke with MRI or CT imaging

  2. VFS-confirmed dysphagia

  3. score of 21 in Mini-Mental State Examination (MMSE)

  4. able to consent

  1. Swallow Function Scale (Freed, Freed et al. 2001)

  2. Penetration –Aspiration Scale (VFS) (Rosenbek, Robbins et al. 1996)

  3. Pharyngeal Transit times (PTT) (10ml semi-solid and liquid boli)

  4. VAS for discomfort and satisfaction during treatment

  5. Tube feeding ratio

 EG: 16 patients NMES (mean age: 67.8 yrs old) (1hr, 5days/wk, low intensity: 7 mA, 80Hz, Placement 3) +Thermal Stimulation (5trials/week, 4 wks)

CG: 12 patients (60.8 yrs old) Thermal Stimulation

(5 trials/week, 4 wks)

  1. significant increase in the swallowing function scale in the EG.

  2. significant change in PA scores in EG for liquid and semi-solids

  3. Change in PTT was greater for EG post treatment.

  4. no significant change in discomfort scales. EG satisfactory scores increased significantly compared to CG.

  5. 6/12 of EG progressed to oral feeding, 1/7 in CG

 Functional Physiological Immediately: 4 weeks post inclusion
Permsirivanich et al, 2009 randomised controlled Trial 23 stroke patients

Recruited 2 weeks after lesion

With “pharyngeal dysphagia with safe swallowing”

  1. FOIS

  2. Number of therapy sessions

  3. Complications during therapy

 EG: 12 patients (mean age: 64.5 years old)

NMES+ Oral motor exercises+ diet modification
NMES: Placement 1, 80Hz, 700 pulse duration)

CG: 11 patients (mean age:64.7 yrs old)
Traditional Therapy (therapeutic maneuvers and techniques )

20 sessions over 4 weeks (60 mins on 5 days/week)

  1. non-significant difference between EG and CG for the number of therapy sessions

  2. significant change on FOIS for the EG compared to CG (p<0.001)

    No comment on complications during treatment

 Functional 1 week before and 1 week post treament
Ryu et al, 2009 randomised controlled Trial 26 Mixed aetiology

all types head/neck cancer

  1. with surgical or radiation treatment for head and neck cancer

  2. dysphagia as a treatment complication

  3. with VFS confirmed dysphagia

  4. on restricted diet, with stable vital signs

  5. ‘ability to participate’

  1. Functional dysphagia scale (FDS)

  2. Clinical dysphagia scale (CDS)

  3. ASHA NOMS

  4. M.D. Anderson dysphagia Inventory (MADI)

 EG: 14 patients (mean age: 63.4yrs) : NMES (30 mins, 80 Hz, 700 ms pulse duration, placement 3B) plus Traditional therapy (30 mins, therapeutic maneuvers)

CG: 12 patients (mean age: 60.8 yrs old)Sham TENS low
Intensity plus Traditional Therapy (therapeutic maneuvers and techniques)

10 sessions of 30 mins for

5 days/week over 2 weeks

  1. statistical significant change observed in FDS for EG compared to CG (p=0.04)

 Functional Immediate evaluation: 2 weeks post inclusion
Bulow et al, 2008 randomised controlled Trial 25 stroke patients

Inclusion criteria:

  1. 50–80 years old

  2. one or more hemispheric CVA, no brainstem involvement, more than 3 months post lesion

  3. no NG tube-fed, PEG-fed included

  4. ability to elicit pharyngeal swallow, anterior hyoid bone and constrictor activity previously observed in VFS

  5. communication ability

  1. Videofluoroscopy (VFS): 5 ml thin and thick boli, temporal and misdirection measurements

  2. Nutritional status scale (non-standardised)

  3. Oral motor function test (non-standarised)

  4. VAS self-evaluation of complaints

 EG: 12 patients NMES (mean age: 70 years old) (Placement 3B, mean 13 mA.)

CG: 13 patients (mean age:71 years old) Traditional Therapy (therapeutic maneuvers and techniques)

15 therapy sessions of 60 mins over 3 weeks (5 days/week)
  • b)

    no statistical difference between CG and EG.

  • b)

    low correlation between measurements

  • c)

    low correlation between objective evaluation and patient experience of improvement

 Functional Physiological Immediate evaluation: 3 weeks post inclusion
Carnaby et al, 2008 prospective case studies 6 stroke patients (mean: 63.6 yrs old, 5.1 yrs post stroke)

Inclusion criteria:

  1. ability to participate in an NMES-based treatment program

  2. MMSE score of 23 or greater

  3. FOIS score of 5 or less

  4. pharyngeal dysphagia on VFS

  5. failure to respond previous swallowing therapy

  1. FOIS (clinical improvement of 2 points)

  2. MASA (clinical improvement of 10 or more points)

  3. Hyoid and laryngeal kinematics (VFS thin, nectar thick, pudding of 5ml and 10ml)

  4. Bodyweight

  5. patients’ perceptual evaluation

 EG: NMES Placement 1), 80 Hz, 700 μs PLUS standardised across patients Traditional Therapy
15 sessions NMES, 1 hour/day or until level 6 on FOIS

  1. significant change on clinical swallowing ability (MASA) (p<0.042)

  2. significant improvement in FOIS scale (p<0.02)

  3. significant weight increase (p<0.026)

  4. significant change of patients’ perception (p<0.043)

  5. no significant change between post-treatment and 6 months clinical outcome measurements

 Functional Physiological Quality of life immediately post-treatment and 6 months follow-up
Oh et al, 2007 uncontrolled prospective case series 8 dysphagic stroke patients, mean age: 57yrs (4 fem, 57 yrs old, 4 hemispheric)

Inclusion criteria:

  1. food residues occupying more than 50% of valleculae or pyriform sinuses post swallowing

  2. subglottic aspiration

  3. pharyngeal time >2s

  4. impaired UES

  1. DOSS

  2. TMS topographic maps of cricothyroid muscle (Centre of Gravity) after 12 hours.

  3. VFS Functional Severity Scale

 EG: NMES 10 sessions of 1h/day for 2 weeks

Placement as Freed et al, 2001

NMES: at varying intensities, 70 Hz 300μs

  1. significant Increase in DOSS (p=0.042)

  2. significant Increase in VFS Functional Scale (p=0.035)

  3. no change in TMS measures, but CoG moved anteriorly

 Functional Neurophysiological Immediately post-treatment
Shaw et al, 2007 retrospective case series 18 patients mixed aetiologies (mean age: 59.3 yrs, range: 42 to 82 yrs)

10/18 consumed all food consistencies prior to therapy

  1. Diet modification

  2. Laryngeal elevation

  3. Penetration/aspiration

  4. Swallow delay

  5. Overall dysphagia severity score

  6. Residue severity

 EG: 1hour NMES for sessions ranging from 7 to 28

NMES : 4 different electrode placements

  1. 50% patients improved dysphagia severity score (p<.05)

  2. “entire” group statistical signifianct improvemnt p<.05 in diet intake, penetration/aspiration, resideus, ovrall severity score

  3. 7/11 telephone screened patients reported improvement in swallowing (range of survey time: 1 to 21 months post treatment)

 Functional Physiological immediate post treatment and telephone screen range of survey time: 1 to 21 months post treatment
Blumenfeld et al, 2006 nonconcurrent cohort study 80 patients (mixed aetiologies) (mean age: 72±11 yrs)

  1. Functional dysphagia scale (FDS)

  2. Number of therapy sessions

  3. Length of hospital stay

 EG:40 patients

30 minutes of NMES therapy

NMES: Placement 2 superior, 80 Hz, 700us pulse duration

CG: 40 patients (mean age: 30 minutes of traditional therapy

Traditional Therapy (therapeutic maneuvers and techniques )

  1. mean improvement with NMES compared to CG (p=0.002

  2. less treatment sessions with NMES (p=0.014)

  3. change in PTT was greater for EG post treatment.

  4. no significant change in LOHS

 Functional NA
Kiger et al, 2006 non-randomised controlled trial 22 mixed aetiologies (mean age: 67.5 yrs old)

Inclusion criteria:

  1. swallowing disorder

    Exclusion criteria:

  2. dementia or nonstop verbalisation

  3. singificant reflux from the use of feeding tube

  4. dysphagia due to drug toxicity

  5. agitation, with decreased level of consiousness, or otherwise non-compliant

  6. pregnancy

  1. Swallowing severity scale oral and pharyngeal (VFS or FEES)

  2. Diet consistency change

 EG:11 patients (mean age: 63.4 yrs old)

NMES: Placement 1, 80 Hz, 700us pulse duration

CG: 11 patients (mean age:71.5 yrs)

Traditional Therapy (therapeutic maneuvers and techniques)

  1. CG more improved in the oral phase than EG (p>11.00, x2 test)

  2. no statistical significant difference for pharyngeal phase between EG and CG

  3. no statistical significant difference for diet advancement between EG and CG

  4. mean number of sessions for EG:8.72, for CG:3.36

 Functional Physiological Immediately post treatment (varying sessions)
Leelamanit et al 2002 non-controlled prospective case series 20/23 mixed aetiologies (age range 35–87 yrs, mean age: 65yrs)

Inclusion criteria:

Dysphagia resulting from reduced larygneal elevation following the criteria:

  1. history of dysphagia and aspiration

  2. wet phonation and/or aspiration during wet swallows

  3. laryngeal penetration/aspiration, reduced Laryngeal elevation, narrow pharyngoesophageal segment on VFS

  4. palpation showing reduced laryngeal elevation

    Exclusion criteria:

    paralysis of superior +recurrent laryngeal nerve or glossopharyngeal nerve

  1. Increased ability to swallow more than 3ml water without apiration or coughing

  2. Adequate oral intake and body weight gain

  3. VFS for i)laryngeal penetration, measured with maximum volume of water without aspiration, ii)laryngeal elevation in 2 swallows iii) PE segment width

 EG: NMES (synchromised electrical stimulation)

NMES: 60Hz, 4 hours daily until ‘improved swallowing’: ‘successful treatment’

During NMES encouraged to continue Oral feeding

  1. 6 patients relapsed 2 to 9 months after initial success (treated with a second course)

  2. Kaplan-Meier analysis of duration of initial of treatment revealed significant effects of initial severity and age

 Functional Monthly follow-up (range 3–33 months)
Freed et al, 2001 non-randomised controlled trial 99/125 Stroke patients already treated with swallowing treament

with confirmed swallowing disorders in VFS

Exclusion criteria:

  1. inability to complete at least 2 consecutive days of therapy

  2. behavioral disorder

  3. substantial reflux from feeding tube

  4. dysphagia from drug toxicity

  1. Swallowing Function Scoring System

  2. Descriptive characteristics

  3. Treatment stopped when the patients were able to swallow thin liquids

 EG: NMES (n=63 patients, mean age: 75.7 yrs) Inpatients: 1 hour and 10 minutes of challenge/assessment. Outpatients: 3 times/week for 1 hour.
(varying intensity, 80 Hz, at 300μs, pause every minute, electrodes preferrable to the right)

CG: Thermal Tactile stimulation (n=36 patients, mean age: 78.1yrs) (3 of 20 minutes interval)Attempts to dry swallow challenged with thickened liquids (20 minutes, 3 times/day)

  1. similar number of treatments (average for EG: 5.5 and CG: 6.0)

  2. improvement in final swallows scores bigger for EG

 Functional Medical records for 3 years
Long-term results of e-stim following a therapeutic regime in a healthy population
References Study Type Subjects/etiology Evaluation techniques Treatment groups Authors conclusion Outcome measures Follow-up post intervention
Park et al, 2009 experimental and control groups 16 healthy participants (mean age: 26.3 ± 2.4 yrs)

  1. Submental muscle electrical activity (surface EMG)

  2. Hyoid excursion by VFS

 EG: 8 healthy NMES Motor threshold (Placement 3A, 35Hz phase duration 200 μs, intensity: 4.38 ± 1.3)
CG: 8 healthy NMES at Sensory threshold (Placement 3A, 35Hz phase duration 200 μs, intensity: 2.00 ± 0)

20 minutes session (2x10 minutes) for 2 weeks

2ml water every 10 s during ‘ON’ state

  1. no significant change for sEMG pre and post-treatment

  2. increased hyoid elevation only in EG, but no forward hyoid movement. Result faded within 2 weeks

 Physiological 2 and 4 weeks post treatment
Suiter et al, 2006 crossover design ABBA 8 subjects (male: mean age: 27 ± 5.3yrs; female: 25 ± 0.5yrs )

  1. sEMG of 5 ml water swallowing at 2 and 4 weeks post intervention

 EG: condition B: 10 sessions of 1hr NMES over 2 weeks
NMES fixed 80 Hz, pulse duration 700 ms

CG: condition A: no treatment
  • c

    no significant difference between Condition A and B

 Physiological Immediate results post 2 weeks intervention

EG, experimental group; CG, control group.