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. 2022 Dec 6;280(3):1017–1045. doi: 10.1007/s00405-022-07735-7

Table 1.

Single swallowing interventions in included studies (including participants, exercise descriptions and dosages, outcome measures and pre–post Hedges g effect sizes in exercise-based intervention group) grouped by exercise type

Study Number of participants (mean age in years ± SD) Mean time post CVA ± SD Description of exercise Intensity Frequency (per day/week) Duration Outcome measures Effect sizes (if p < 0.05)
Cervical isometric strength training
Ploumis et al. (2018) [70]

T: 70 (52 ± 15)

Expa: 37

Con: 33

2.5 ± 1.1 d Contract neck muscles forwards–backwards–sidewards against resistance 4 reps in all 4 directions for 10 min 3x/day 12 weeks

Change of sagittal and coronal C2–C7 Cobb angle

VFSS score

NR
Chin tuck against resistance
 Gao and Zhang (2017) [31]

T: 90

CTARa: 30 (70.88 ± 6.6)

Shaker: 30 (71.12 ± 7.07)

Con: 30 (71.14 ± 6.41)

CTAR: 12.95 ± 1.60 d

Shaker: 13 ± 1.41 d

Con: 12.15 ± 1.35 d

Chin tuck against an inflatable rubber ball as far as possible while seated 30 reps 3x/day, 7x/week 6 weeks PAS g = 1.33
 Kim and Park (2019) [71]

CTARa: 12 (63.5 ± 5.5)

Con: 13 (65.2 ± 6.2)

 < 6 mos PhagiaFlex-HF device fixed to the desk and height adjusted so device was under the chin. Chin down exercises performed against device

Isometric: 10 s hold × 3

Isotonic: 30 reps

5x/wk 6 wks

PAS

FOIS

g = 1.99

g = 1.60

 Park et al. (2018) [52]

CTARa: 11 (62.16 ± 17.27)

Con: 11 (58.43 ± 12.51)

Exp: 37.24 ± 8.54 wks

Con: 32.14 ± 14.38

Isometric and isokinetic chin tucks against CTAR device as strongly as possible in sitting position Isometric: 60 s hold × 3 Isokinetic: 30 reps 5x/wk 4 wks

FDS

PAS

g = 1.02

g = 1.69

 Park et al. (2019) [72]

CTARa: 19 (60.95 ± 11.19)

Shaker: 18 (59.45 ± 9.34)

CTAR: 3.6 ± 1.19

Shaker: 3.85 ± 1.18

LES 100 CTAR device was used with a resistance bar placed beneath the chin. 1-RM was determined. A tablet PC was used to display targets

70% of 1-RM. Isometric: 60 s chin tuck × 3

Isotonic: 30 consecutive reps

5x/day 4 wks

VDS oral phase

VDS pharyngeal phase

VDS total

PAS

FOIS

g = 0.92

g = 2.16

g = 2.34

g = 1.54

g = 1.16

Effortful swallowing
 Cho et al. (2017) [73] 9 (age NR) NR Press tongue firmly against the palate while swallowing as hard as possible 30 reps 5x/wk 4 wks

VDS oral phase

VDS pharyngeal phase

g = 0.74

g = 0.32

 Park et al. (2019) [62]

Expa: 12 (66.5 ± 9.5)

Con: 12 (64.8 ± 11.2)

Exp: 24.39 ± 8.65 wks

Con: 25.74 ± 6.27 wks

Push tongue firmly onto palate while squeezing neck muscles and swallow as forcefully as possible 10 reps 3x/day, 5x/wk 4 wks

Ant. tongue strength

Post. tongue strength

VDS

g = 1.51

g = 1.23

g = 1.32

 Wei et al. (2017) [63]

Cona: 15 (57.9 ± 9.3)

Exp: 15 (57.7 ± 8.8)

Con:4.5 ± 2.3 mos

Exp:4.3 ± 2.6 mos

Swallow as hard as possible using mouth muscles without recruiting abdominal/stomach muscles 10 reps per day 2x/day, 5x/wk 3 wks (or if no longer tube fed)

Motor evoked potentials

UES displacement

Max UES opening

FOIS

NR
Expiratory muscle strength training (EMST)/Respiratory training
 Arnold et al. (2020) [45]

Expa: 10 (70.5 ± NR)

Con: 10 (66.1 ± NR)

NR Forcefully inhale and exhale through Breather device using diaphragmatic breathing technique with nose clip in place 5 min × 3 sets at highest tolerated settings on device 3x/day, 7x/wk 4 wks

PEFR

PAS

FOIS

VAS

MASA

g = 3.04

g = 2.19

g = 1.63

g = 2.15

g = 2.32

 Eom et al. (2015) [64]

Expa: 13 (69.2 ± 4.1)

Con: 13 (70.2 ± 3.6)

 < 3 mos Blow strongly and rapidly into EMST device until pressure release valve opens (at > 70% of MEP) 5 breaths (< 1 min break between sessions) 5x/day, 5x/wk 4 wks

VDS

PAS

g = 1.68

g = 1.49

 Guillen-Sola et al. (2017) [37]

IEMTa: 21 (67.9 ± 10.6)

NMES: 20 (70.3 ± 8.4)

Con: 21 (68.9 ± 7)

IEMT:10.8 ± 8.7 d

NMES: 11 ± 5.5 d

Con: 9.3 ± 5.1 d

Respirations at 30% of max inspiratory and expiratory pressures and increased by 10cmH2O each week. 1 min of recovery breathing off the device 5 sets of 10 reps 2x/day, 5x/wk 3 wks

PAS

FOIS

DOSS

Max. inspiratory pressure

MEP

NR
 Hegland et al. (2016) [65] 14 (64.5 ± 7.4) 11.9 ± 7.9 mos With noseclips on, exhale quickly and forcefully into EMST device until valve opens (at 60% of MEP) 5 reps 5x/day, 5x/wk 5 wks

MEP

PEPR vol. cough

PEPR cough reflex

VA vol. cough

VA cough reflex

MBSImp

PAS

g = 0.85

n/s

g = 1.41

n/s

g = 0.67

g = 1.55

NR

 Liaw et al. (2020) [55] Expa: 11 (65.4 ± 11.54) Con: 10 (60.44 ± 10.65)  ≥ 6 mos Inspiratory muscle training (IMT): inhale deep and forceful breaths sufficient for opening the valve. Expiratory muscle training (EMT): blow fast and forcefully to open the valve

IMT: 30–60% of max pressure

EMT: 15–75% of MEP × 5 reps for 5 sets each

1–2x/day (1–2 min rest), 5x/wk 6 wks

Change in max. inspiratory pressure

Change in MEP

FVC

FEV1

FOIS

g = 1.33

g = 1.10

n/s

n/s

g = 1.11

 Moon et al. (2017) [50]

Expa: 9 (63 ± 5.8)

Con: 9 (63.1 ± 5.2)

Exp: 21.4 ± 5.1 d

Con: 21.1 ± 4 d

Take a deep breath and bite the EMST mouthpiece. Close nostrils and blow fast and strong into device (set at 70% of MEP) 7 reps 5x/wk 4 wks

FDS

PAS

Vallecular residue

Pyriform sinus residue

g = 1.70

g = 1.79

g = 2.05

g = 0.93

 Park et al. (2016) [67]

Expa: 14 (64.3 ± 10.7)

Con: 13 (65.8 ± 11.3)

Exp:27.4 ± 6.3 wks

Con:26.6 ± 6.8 wks

After max inhalation, blow strong and fast into EMST device between lips until pressure release valve opens (at 70% MEP) 5 reps (< 1 min break after each session) 5x/day, 5x/wk 4 wks

Suprahyoid muscle activity

PAS (liquids)

PAS (semisolids)

FOIS

g = 1.14

g = 1.93

g = 1.02

g = 1.47

Game-based biofeedback
 Stepp et al. (2011) [28] 1 (18) 6 yrs Swallow at target strength/length (33%, 66% and 100% of max swallow strength for 2.8, 3.5 or 4.7 s) to “eat” the 7 swallow targets (depicted as fish on sEMG machine) 7 reps for 10 sets of 2 min (1–2 min breaks and > 5 min between sets 5–6) 3x/wk 3 wks

Number of targets per session

Neck intermuscular beta coherence

NR
Jaw opening exercise
 Choi et al. (2020) [58]

Jaw openinga: 11 (63.5 ± 7.7)

Head lift: 10 (61.2 ± 9.7)

Jaw opening: 12.1 ± 2.2wks

Head lift: 13.4 ± 2.2wks

Hold jaw open against resistance bar (isometric). Open jaw against resistance bar (isotonic)

Isometric: 10 s hold × 3 reps

Isotonic: 3 sets of 30 reps

5x/wk 6 wks

Muscle thickness:

 Digastric

 Mylohyoid

Hyoid movement:

 Anterior

 Superior

BRPES

g = 0.62

g = 1.06

g = 1.1

g = 0.89

NR

 Koyama et al. (2017) [66]

Expa: 6 (66.0 ± 9.3)

Con: 6 (71.8 ± 7.6)

Exp: 6.7 ± 2.1 mos

Con: 9.2 ± 4 mos

Press tongue against hard palate. Open mouth against resistance (trainer’s hand pushing chin up). Muscle contraction measured with surface electrodes 80% MVC 6 s hold × 5 reps 4x/day, 5x/wk 6 wks

Distance between mental spine and hyoid bone

Hyoid displacement:

 Superior

 Anterior

g = 0.41

n/s

g = 1.26

 Oh et al. (2017) [74] 3 (age NR)  < 12mos Open mouth against external resistance (38 cm circumference ball)

Isometric: hold for 60 s,

Isotonic: 30 reps

5x/wk 4 wks PAS (liquids) g = 2.04b
 Park et al. (2020) [54]

Expa: 20 (62.1 ± 10.1)

Con: 20 (61.8 ± 12.1)

 < 6mos Resistive jaw opening device affixed to the sternum and resistive portion placed below chin. Depress the resistive jaw opening device

Isometric: hold for 30 s × 3 reps

Isotonic: 2–3 s × 10 reps (30 s rest)

3x/day, 5x/wk 4 wks

Hyoid movement:

 Anterior

 Superior

PAS (semisolids)

PAS (liquids)

FOIS

g = 0.9

g = 0.7

g = 0.6

g = 0.6

g = 1.1

 Wada et al. (2012) [35] 8 (70.5 ± 11.3) Chronic Open jaw to max extent 10 s hold × 5 reps (10 s rest between reps) 2x/day, daily 4 wks

Movement of hyoid:

 Upward

 Forward

UES opening width

Time for pharynx passage

g = 0.99

n/s

g = 0.36

g = 0.90

Lip muscle training
 Hagg and Anniko (2008) [75] 30 (70 ± 9.75) 1 mos (2 days–10 yrs) Hold an oral screen predentally between closed lips as screen is gradually pulled away 5–10 s hold × 3 reps 3x/day, 7x/wk At least 5 wks

Lip force meter

Swallowing capacity test

g = 1.40

g = 1.79

 Hagglund et al. (2020) [59]

Expa: 18 (75, range: 56–90)

Con: 14 (75, range: 60–85)

NR Hold oral device (Muppy) predentally behind closed lips against a gradually increasing horizontal pulling force 5–10 s hold × 3 reps

3x/day,

daily

5 wks

TWST

Lip force

PAS

NR

NR

NR

 Park et al. (2018) [76] 10 (age NR)  ≤ 6 mos Press IOPI bulb between lips 70% of 1–RM × 30 reps/wk 5x/wk 4 wks

Lip strength

Lip closure on VFSS

g = 0.98

g = 1.05

Masako maneuver
 Kumaresan et al. (2018) [77] 30 (age NR) NR Protrude tongue and gently bite down on the anterior part of the tongue while swallowing saliva 10 reps × 3 3x/day 2 wks EAT-10 g = 9.86
Mendelsohn maneuver
 Bogaardt et al. (2009) [36] 11 (61.1 ± 7.6) 30.6 ± 42.4mos Modified maneuver: prolong laryngeal excursion for 8–10 s with sEMG feedback Instructed to practise without sEMG 2–3x/day (40–60 reps) 1x/wk (or 1x/fort-night) 6.4 sessions and 76.1 days (mean) FOIS g = 1.46
 McCullough and Kim (2013) [78] Crossover group: 18 (70.2 ± 11.5; range: 42–88) 9.5 ± 4; range: 6–22mos Swallow “long and strong” with a squeeze at the peak of the swallow for 3–4 s with sEMG feedback

Target set at 5 μV above mean

30–40 swallows,

45–60 min

2x/day (2–3 h breaks) 2 wks

Max hyoid:

 Anterior excursion

 Elevation

UES opening width Duration of:

 Hyoid elevation

UES opening

DOSS

n/s

n/s

n/s

n/s

n/s

n/s

 Wei et al. (2017) [63]

Cona: 15 (57.9 ± 9.3)

Exp: 15 (57.7 ± 8.8)

Con: 4.5 ± 2.3 mos

Exp: 4.3 ± 2.6 mos

Swallow the bolus by pressing tongue against hard palate and squeezing the throat muscles. Maintain swallow for 2 s 10 reps 2x/day, 5x/wk 3 wks (or if no longer tube fed)

Motor evoked potentials

UES displacement

Max UES opening

FOIS

NR
Proprioceptive Neuromuscular Facilitation (PNF)-based short neck flexion exercises
 Kim et al. (2015) [79]

Expa: 13 (63.2 ± 10.2)

Con: 13 (63.6 ± 8.1)

Exp:15.6 ± 2.9 mos

Con:16.15 ± 3.1 mos

While supine with head/neck off the bed, look at target object 15° diagonally to the right, while the tester moves the participant’s neck in the opposite direction. Repeat in the opposite direction 30 min 3x/wk 6 wks

New VFSS scale

ASHA NOMS

g = 1.97

g = 0.67

Shaker head lift
 Cho et al. (2017) [73] 9 (age NR) NR Lift the head while in lying position (isometric and isokinetic)

Isometric: 60 s hold

Isokinetic: 30 reps

5x/wk 4 wks

VDS oral phase

VDS pharyngeal phase

g = 0.74

g = 0.32

 Choi et al. (2017) [47]

Expa: 16 (60.81 ± 10.85)

Con: 15 (60.4 ± 10.5)

Exp:3.44 ± 1.15mos

Con: 4.13 ± 0.99mos

Head lift high enough to observe toes in supine position (isometric and isokinetic) Isometric: 60 s hold × 3 reps (60 s rest) Isokinetic: 30 reps 5x/wk 4 wks

PAS

FOIS

g = 2.06

g = 1.57

 Choi et al. (2020) [58]

Head lifta: 10 (61.2 ± 9.7)

Jaw opening: 11 (63.5 ± 7.7)

Head lift: 13.4 ± 2.2wks Jaw opening: 12.1 ± 2.2wks Lift head and hold (isometric). Lift head and lower (isotonic)

Isometric: 10 s hold × 3 reps

Isotonic: 3 sets of 30 reps

5x/wk 6 wks

Muscle thickness:

 Digastric

 Mylohyoid

Hyoid movement:

 Anterior

 Superior

BRPES

g = 0.91

g = 1.28

g = 1.29

g = 0.91

NR

 Gao and Zhang (2017) [31]

Shakera: 30 (71.1 ± 7.07)

CTAR:30 (70.88 ± 6.6)

Con:30 (71.14 ± 6.41)

Shaker: 13 ± 1.41 d

CTAR:12.95 ± 1.6 d

Con:12.15 ± 1.35 d

Raise head and neck to look at feet from supine position (isokinetic only) 30 reps 3x/day, 7x/wk 6 wks PAS g = 1.33
 Kim et al. (2015) [79]

Cona: 13 (63.6 ± 8.1)

Exp: 13 (63.2 ± 10.2)

Con:16.15 ± 3.1 mos

Exp:15.6 ± 2.9 mos

Lie on bed and raise head without moving shoulders to look at feet and hold (isometric and isokinetic)

Isometric: 60 s × 3 (60 s rest)

Isokinetic: 30 reps

30 min

3x/wk 6 wks

New VFSS scale

ASHA NOMS

g = 1.48

g = 2.33

 Logemann et al. (2009) [32]

Expa: 8 (63.1 ± 22.8)

Con: 11 (70.9 ± 9.5)

 > 3mos Isometric head lifts in supine position (with rest between lifts) followed by consecutive isokinetic reps

Isometric: 60 s × 3

Isokinetic: 30 reps

Practice 3x/day, 2x/wk 6 wks

Hyoid movement:

 Anterior

 Superior

n/s

n/s

Laryngeal movement:

 Anterior

 Superior

Max UES opening

n/s

n/s

n/s

 Mepani et al. (2009) [34]

Expa: 5 (64 ± 22.8)

Con: 6 (70.5 ± 9.5)

 > 3 mos Raise head high and forward enough to observe toes while in supine position. Isometric head lifts with rest period followed by consecutive head lifts at constant velocity without rest (isokinetic)

Isometric: 60 s hold × 3 (60 s rest)

Isokinetic: 30 reps. 45 min

2x/wk 6 wks Thyrohyoid muscle shortening g = 1.08
 Park et al. (2017) [53]

Expa: 13 (59.26 ± 11.94)

Con: 14 (61.59 ± 13.61)

Exp: 21.29 ± 8.92 wks

Con: 19.2 ± 5.65 wks

Raise head to look at toes and hold (isometric) without lifting shoulders in supine position (rest period between lifts) followed by × 30 isokinetic consecutive reps

Isometric: 60 s hold × 3 (60 s rest)

Isokinetic: 30 reps

5x/wk 4 wks

PAS (liquids)

PAS (semisolids)

Hyoid displacement:

 Horizontal

 Vertical

Larynx displacement:

 Horizontal

 Vertical

g = 1.78

g = 0.97

g = 1.01

g = 1.25

g = 0.48

g = 0.57

 Park et al. (2019) [72] Shakera: 18 (59.45 ± 9.34) CTAR: 19 (60.95 ± 11.19)

Shaker: 3.85 ± 1.18

CTAR: 3.6 ± 1.19

Raise head to look at toes and hold (isometric) without lifting shoulders in supine position, followed by isokinetic consecutive reps

Isometric: 60 s hold × 3

Isotonic: 30 consecutive reps

5x/day 4 wks

VDS oral phase

VDS pharyngeal phase

VDS total

PAS

FOIS

g = 0.98

g = 1.71

g = 1.87

g = 0.95

g = 0.74

 Shaker et al. (2002) [38] 27 (73.37 ± 6.21) 8.63 ± 18.54 mos Lie flat and perform sustained head raisings (isometric) with rest periods, followed by consecutive isokinetic head raisings (high and forward enough to observe toes)

Isometric: 60 s hold × 3 (60 s rest)

Isokinetic: 30 reps

3x/day 6 wks

UES opening

Laryngeal excursion

 Anterior

 Superior

Hyoid excursion

FOAMS

g = 3.48

g = 1.91

n/s

n/s

g = 6.66

Swallowing with kinesiology taping
 Jung et al. (2020) [60]

Expa: 13 (71.3 ± 6.5)

Con: 14 (70.5 ± 8.2)

Exp: 16.2 ± 5.2 wks

Con: 15.1 ± 6.4 wks

Voluntary swallow with kinesiology tape attached to the hyolaryngeal complex, pulled downward with approx. 70% tension and attached to the sternum and clavicle bilaterally 5 sets of 10 swallows against kinesiology tape tension 10x/day, daily 4 wks

Muscle thickness:

 Tongue

 Mylohyoid

 Anterior belly of digastric

g = 0.55

g = 1.24

g = 0.83

Supraglottic swallow
 Wei et al. (2017) [63]

Cona: 15 (57.9 ± 9.3)

Exp: 15 (57.7 ± 8.8)

Con:4.5 ± 2.3 mos

Exp:4.3 ± 2.6 mos

Hold breath before and during swallow, and cough/clear throat after swallow before breathing 10 reps 2x/day, 5x/wk 3 wks (or if no longer tube fed)

Motor evoked potentials

UES displacement

Max UES opening

FOIS

NR
Tongue strengthening exercises
 Cho et al. (2017) [73] 9 NR Press tongue strongly against hard palate 30 reps 5x/wk 4 wks

VDS oral phase

VDS pharyngeal phase

g = 0.74

g = 0.32

 Juan et al. (2013) [27] 1 (56) 27 mos Press tongue against bulb placed between hard palate and either anterior or posterior tongue 60% of 1-RM for 1st wk; 80% of 1-RM onwards × 10 reps Therapy: 3x/day, 3x/wk 8 wks therapy

Lingual pressures

 Ant

 Post

Lingual volume

SWAL–QOL

N/A
 Kim et al. (2017) [61]

Expa: 18 (62.17 ± 11.01)

Con: 17 (59.29 ± 10.19)

Exp: 4.94 ± 5.52 mos

Con: 5.29 ± 5.62 mos

Press tongue strongly against palate for anterior and posterior tongue regions in a random sequence 30 reps 5x/wk 4 wks

Ant. tongue strength

Post. tongue strength

VDS oral phase

VDS pharyngeal phase

PAS

g = 0.89

g = 1.41

g = 1.06

g = 0.91

g = 2.26

 Moon et al. (2018) [51]

Expa: 8 (62 ± 4.17)

Con: 8 (63.50 ± 6.05)

Exp: 56 ± 17.35 d

Con: 59.88 ± 20.04 d

Ex1: Press tongue tip on bulb at posterior alveolar arch and press middle portion of tongue on bulb at middle of the hard palate

Ex2: generate precise pressures (± 10 kPa of target)

Ex1: 6 reps × 5

Ex2: Targets at 50, 75 and 100% of max pressure

30 min

5x/wk 8 wks

Ant. MIPs

Post. MIPs

MASA

SWAL–QOL

g = 3.17

g = 4.50

g = 5.73

g = 3.40

 Park et al. (2015) [49]

Expa: 15 (67.3 ± 10.6)

Con: 14 (65.8 ± 11.5)

Exp: 25.37 ± 7.43 wks

Con: 26.38 ± 6.81 wks

Press IOPI bulb toward hard palate with tongue as hard as possible in anterior and posterior positions 2 s hold at 80% of 1-RM × 10 reps 5x/day (min. 30 s rest), 5x/wk 6 wks

Ant. MIPs

Post. MIPs

VDS

g = 0.26

g = 0.50

g = 0.36

 Robbins et al. (2007) [68] 10 (69.7 ± 13.66)

1 mos (n = 6),

5 to > 48 mos (n = 4)

Compress IOPI bulb between tongue and hard palate for anterior and posterior tongue 60% of 1-RM for 1st wk and 80% of 1-RM onwards × 10 reps 3x/day, 3x/wk 8 wks

Change in MIPs (IOPI)

Swallowing pressure Oropharyngeal residue

PAS

Durational measures

MRI

SWAL–QOL

Dietary questionnaires

NR
 Steele et al. (2016) [69] 14 (71 ± 13.43) 70.29 ± 42.21 d

Strength training:

Ex1: post. MIPs, regular and effortful saliva swallows

Ex2: post. MIPs with slow-release trials

Ex3-4: effortful and regular saliva swallows with slow-release trials

Ex5: nectar-thick liquid swallows with slow-release

Accuracy training:

Ex1: ant. and post. MIPs

Ex2-3: ant. and post. tongue MIP trials

Ex4-5: ant. and post. tongue target accuracy trials

Strength:

Ex1: 5 reps each

Ex2: 20 reps

Ex3-4: 10 reps each

Ex5: 5 reps

Accuracy:

Ex1: 5 reps

Ex2-3: 10 reps

Ex4-5: 15 reps each (25–85% of MIP)

2–3x/wk 8–12 wks

Post. MIPs

Stage transition duration (from VFSS)

PAS

Normalised Residue Ratio Scale

NR

n/s

n/s

NR

NR

 Yeates et al. (2008) [29] 1 (72) 7 mos

Ant. and post. tongue-to-palate presses (half isometric strength, half accuracy)

Strength: press bulb to roof of mouth as hard as possible. 1 set of tongue presses in ant. position coupled with a swallow

Accuracy: generate precise pressures in ant. or post. tongue positions

6 reps × 10 sets in total

Strength:

at max pressure

Accuracy: 50, 75, 100% of MEP

10 sets per day, 2–3x/wk 24 sessions

Ant. and post. tongue bulb pressure (average, accuracy, accuracy relative to strength)

Stage transition duration (from VFSS)

N/A

1-RM 1 repetition maximum, ant. anterior, ASHA NOMS American Speech–Language Hearing Association’s National Outcomes Measurement System, BRPES Borg rating of perceived exertion, C2–C7 cervical vertebrae 2–7, Con control group, CTAR chin tuck against resistance, CVA cerebrovascular accident, d days, DOSS Dysphagia Outcome and Swallow Scale, EAT-10 Eating Assessment Tool-10, EMST expiratory muscle strength training, Ex1,2 exercise 1, 2 etc., Exp experimental group, FDS Functional Dysphagia Scale, FEV1 forced expiratory volume per second, FOAMS Functional Outcome Assessment of Swallowing, FOIS Functional Oral Intake Scale, FVC forced vital capacity, g Hedges’ g, h hour/s, H2O water, IEMT Inspiratory/Expiratory Muscle Training, IOPI Iowa Oral Performance Instrument, kPa kilopascals, LEDT laryngeal elevation delay time, MASA Mann Assessment of Swallowing Ability, max maximum, MBSImp Modified Barium Swallow Impairment Profile, min minute/s, min. minimum, MEP maximum expiratory pressure, MIP maximum isometric pressure, mos months, MRI magnetic resonance imaging, MVC maximum voluntary contraction, NMES neuromuscular electrical stimulation, NR not reported or not calculable, n/s not significant, PAS Penetration–Aspiration Scale, PEFR peak expiratory flow rate, post. posterior, reps repetitions, RSST Repetitive Saliva Swallowing Test, s seconds, sEMG surface electromyography, SD standard deviation, SWAL–QOL Swallowing Quality-of-Life questionnaire, T total, TWST Timed Water Swallow Test, μV microvolts, UES upper oesophageal sphincter, VA volume acceleration, VAS visual analogue scale, VDS Videofluoroscopic Dysphagia Scale, vol voluntary, VFSS Videofluoroscopic Swallow Study, vs versus, wk/s week/s, WST Water Swallowing Test (WST), x/times per, yrs years

aIntervention, dosage and effect sizes reported for the first listed group (with studies containing > 1 group)

bNot reported whether results were significant or not