Table 1 Main characteristics of selected studies analyzing validity of the myotonometry in the upper limbs.

Chuang et al.⁴⁰

N = 67

67 chronic stroke patients

Mean age = 54.67, SD = 10.9

27 women

Mean time post stroke (mo) = 21.12, SD = 13.63

Myoton-3 myometer: Muscle tone, stiffness, and elasticity at rest

MB: Extensor digitorum;

Flexor carpi radialis

Flexor carpi ulnaris

1. Hydraulic hand dynamometer and pinch gauge: Hand strength (grip, lateral pinch and palmar pinch)

2. ARAT test: Arm function

Relaxed supine with 30° to 45° elbow flexion, palm downward for the extensor digitorum and palm upward for flexor carpi radialis and ulnaris (myoton-3 myometer); seated, shoulder adducted and neutrally rotated, 90° elbow flexion, and forearm and wrist in neutral position (hydraulic dynamometer and pinch gauge)

1. Myoton-3 myometer: 3 bilateral trials at rest, 1 s interval. Left side first

2. Hydraulic hand dynamometer and pinch gauge: 3 bilateral trials, 2 to 3 min interval. Left side first

3. ARAT test

Low to fair correlations between myometer scores, hand strength and arm function

No general concurrent patron between outcome measures

Leonard et al.⁴³

N = 20

10 with UMN disorders (6 with stroke and 4 with cerebral palsy)

Mean age = 47.5

4 women

Mean time post stroke = N/A

10 healthy controls

Mean age = 48.3

4 women

Myotonometer:

Muscle compliance at rest and during MVC

MB: Biceps brachii

1. MAS test of the elbow flexor muscles: Muscle tone

Sitting position with 90° elbow flexion and forearm supinated (myotonometer and MAS)

1. Myotonometer: 5 trials at rest and 5 trials during MVC of the biceps brachii. 15 to 30 s rest between trials. Force intervals of 2.5 N over a range from 2.5 to 20 N

Bilateral assessment for subjects with UMN disorders, and on the dominant side for controls

2. MAS test

Moderate to high correlations (0.64–0.81) between MAS scores and percentage differences of the myotonometer (relax vs. MVC)

Li et al.⁴⁴

N = 14

14 chronic stroke patients

Mean age = 61

8 women

Mean time post stroke (mo) = 61, SD = 30

Myotonometer: Muscle compliance at rest

MB: Biceps brachii

1. MAS test of the elbow flexor muscles: Muscle tone

2. Conventional muscle stretch test with a torque sensor:

Reflex and non-reflex elbow flexor torque

Sitting position with 90° elbow flexion and shoulder slightly abducted (myotonometer); and 45° shoulder abduction with 30° shoulder flexion (stretch test)

1. Myotonometer: 8 bilateral trials at rest. Force intervals of 2.5 N over a range from 2.5 to 20 N

2. Muscle stretch test: Ramp and hold protocol. 2 s rest, constant velocity stretch of elbow flexors, 2 s holding pause, return to initial position. 50° of total range of stretch at 5°/s or 100°/s. 3 trials with 30 s for each velocity

Reductions in muscle compliance and AUC between the spastic and non-spastic sides

Negative moderate association between muscle compliance and AUC and the stretch test at 100°/s

No correlations between MAS scores and muscle compliance