Ton A.R. Schreuders

Manual Muscle Strength Testing: Intraobserver and Interobserver Reliabilities for the Intrinsic Muscles of the Hand

The reliability of manual muscle strength testing of the intrinsic muscles of the hand is reported. The muscle strengths of 28 patients who had neuropathies of the ulnar nerve or the ulnar and median nerves were graded by two physiotherapists to determine intraobserver and interobserver reliabilities. Muscle strength was graded using the numeric scale developed by the Medical Research Council (grades 0 to 5). Reliabilities were established for nine muscles or muscle groups. Intraobserver reliabilities ranged from 0.71 to 0.96 and interobserver reliabilities from 0.72 to 0.93. It is difficult to isolate, and hence grade, most of the intrinsic muscles of the hand. Therefore, it is suggested that specific movements be tested and graded when assessing and evaluating muscle or nerve function.

Strength of the intrinsic muscles of the hand measured with a hand-held dynamometer: reliability in patients with ulnar and median nerve paralysis.

The aim of this study was to assess the reliability of a technique to measure the strength of the intrinsic hand muscles. Intraclass Correlation Coefficients showed an excellent level of reliability for the comparison of muscle strength between groups of patients. However, for the results of individual patients, the calculated Standard Error of Measurements (10–16%) and the Smallest Detectable Differences for intraobserver (31–36%) and interobserver (37–52%) values indicate that only relatively large changes in strength can be confidently detected with this technique. The results of the present study were compared with those of four previous grip strength studies.

Sensible manual muscle strength testing to evaluate and monitor strength of the intrinsic muscles of the hand: a commentary.

Hand therapists often assess, evaluate, and monitor the status of, and changes in the strength of, the intrinsic muscles of the hand. Some common indications are peripheral and central neuropathies and nerve lacerations and repairs. The therapist will often use a muscle chart that lists all the muscles innervated by the ulnar and median nerves, and all muscles will be tested. Not all muscles in the hand can be sufficiently isolated to grade their strength, nor is it always necessary to test all muscles innervated by a particular nerve to evaluate the presence or extent of motor function impairment or monitor changes. This paper discusses the tests by which changes in strength of the ulnar and median innervated intrinsic muscles can be assessed and the reasons that certain muscles cannot or need not be tested. Information about the reliability of muscle testing is also given.

Dynamometry of intrinsic hand muscles in patients with Charcot-Marie-Tooth disease

Background: Several problems are associated with manual muscle testing and dynamometry in the hands of patients with Charcot–Marie–Tooth (CMT) disease. Objective: To evaluate the efficacy of the Rotterdam Intrinsic Hand Myometer (RIHM) to directly measure intrinsic hand muscle strength in CMT disease. Methods: We measured hand muscle strength and hand function in 41 patients with CMT disease. Results: RIHM measurement of intrinsic strength had excellent reliability. We found overlapping RIHM strength values in Medical Research Council grades 3 to 5. High grip and pinch strength could be found in patients with severe intrinsic muscle weakness. RIHM measurements were more strongly correlated with fine motor skills of the hand than grip and pinch strength. Conclusions: The Rotterdam Intrinsic Hand Myometer is a reliable instrument to measure intrinsic hand muscles strength in patients with Charcot–Marie–Tooth disease, providing more detailed information than manual muscle testing and a more direct assessment of intrinsic muscle loss than grip and pinch dynamometers.

Reliability of Hand Strength Measurements Using the Rotterdam Intrinsic Hand Myometer in Children

PURPOSE Grip strength and pinch strength measurements are often used to assess hand function. However, both measure a number of muscle groups in combination, and grip strength in particular is dominated by extrinsic hand muscles. The Rotterdam Intrinsic Hand Myometer (RIHM) was recently introduced to measure the force that individual fingers and thumb can exert in different directions. The aim of this study was to establish the reliability of these measurements with use of the RIHM in children. METHODS Sixty-three healthy children between 4 and 12 years of age participated in this study. The RIHM was used to measure thumb palmar abduction, thumb opposition, thumb flexion at the metacarpal-phalangeal (MP) joint, index finger abduction, and little finger abduction. A retest was performed with an average test-retest interval of 26 days. RESULTS For the thumb, palmar abduction strength had intraclass correlation coefficients (ICCs) of .98 for both hands. For both thumb opposition and flexion at the MP joint, ICCs were .97 for the dominant hands and .98 for the nondominant hands. Index finger abduction had ICCs of .94 and .95 and little finger abduction had ICCs of .90 and .92 for the dominant and nondominant hands, respectively. The smallest detectable differences for dominant and nondominant hands respectively were thumb palmar abduction, 15% and 15%; thumb opposition, 12% and 9%; thumb flexion (at the MP joint), 12% and 9%; abduction of the index finger, 17% and 17%; and little finger abduction, 26% and 26%. CONCLUSIONS We found that the RIHM was reliable for use in children. Intraclass correlation coefficients and smallest detectable differences were comparable with those obtained with use of the RIHM in adults and with values found for pinch and grip strength in children. Because the RIHM measures more specific aspects of hand function than grip and pinch, adding the RIHM to measurement protocols may contribute to a more complete overview of a childs hand function.

Long-term outcome of muscle strength in ulnar and median nerve injury: comparing manual muscle strength testing, grip and pinch strength dynamometers and a new intrinsic muscle strength dynamometer.

OBJECTIVE To compare the outcome of muscle strength with manual muscle strength testing grip and pinch strength measurements and a dynamometer which allows for measurements of the intrinsic muscles of the hand in isolation (the Rotterdam Intrinsic Hand Myometer, RIHM). METHODS Thirty-four patients more than 2 years after ulnar and/or median nerve injury. Muscle strength was evaluated using manual muscle strength testing (MMST), grip, pinch and intrinsic muscle strength measurements. RESULTS Manual muscle strength testing showed that most muscles recover to grade 3 or 4. Average grip strength recovery, as percentage of the uninjured hand, was 83%. Pinch strength recovery was 75%, 58% and 39% in patients with ulnar, median and combined nerve injuries, respectively. The RIHM measurements revealed a poor recovery of the ulnar nerve innervated muscles in particular (26-37%). No significant correlation (Pearson) was found between the measurements of the RIHM and grip strength. Pinch strength was significantly correlated with strength of the abduction of thumb and opposition of the thumb strength (r 0.55 and 0.72, p = 0.026, 0.002) as measured with the RIHM. CONCLUSION While manual muscle strength testing and grip strength measurements show a reasonable to good recovery, measurements of the intrinsic muscles by means of the RIHM showed poor recovery of intrinsic muscle strength after peripheral nerve injury. No correlation was found between the recovery of intrinsic muscle strength and grip strength measurements.

Sensory Evaluation of the Hands in Patients with Charcot-Marie-Tooth Disease Using Semmes-Weinstein Monofilaments

In this study, the intra- and interobserver reliability of the Semmes-Weinstein monofilaments (SWMFs) was determined in the hands of 15 patients with Charcot-Marie-Tooth disease. In addition, the amount and distribution of sensory loss in the hand, and the relation between sensory loss, intrinsic muscle strength, and hand dexterity was explored in 45 patients. SWMF testing had good intra- and interobserver reliability with intraclass correlation coefficients of 0.91 and 0.86, respectively. The SWMF testing revealed normal sensory function in 43% of all six locations. The average loss of the intrinsic hand muscle strength was 57%. Poor strength was found in patients with both poor and with good sensory function. The correlation between the measurements of intrinsic muscle strength and the Sollerman test for dexterity was 0.70.

The Pollexograph: a new device for palmar abduction measurements of the thumb.

STUDY DESIGN Clinical measurement, cross sectional. PURPOSE To introduce a new measurement device, the Pollexograph, to easily measure palmar thumb abduction, and to compare its reliability with conventional goniometry. METHODS Fourteen hand therapists measured palmar abduction of the same healthy subject with the Pollexograph and a conventional goniometer. In addition, intrarater reliability of the Pollexograph was studied in 21 patients with a hypoplastic thumb. RESULTS Variance between measurements of the same subject measured by the hand therapist was 2-6 times smaller with the Pollexograph compared to conventional goniometry. Pollexograph intrarater reliability in hypoplastic thumb patients was excellent (intraclass correlation coefficient (ICC)=0.98-0.99). CONCLUSIONS A new tool to measure palmar abduction in clinical care, the Pollexograph, has been introduced. The Pollexograph reduces variability between raters when measuring the same subject compared with conventional goniometry and excellent measurement reliability in hypoplastic thumb patients. LEVEL OF EVIDENCE Not applicable.

Strength Measurements of the Lumbrical Muscles

This study was designed to measure the strength of the lumbrical muscles in the index and long fingers in patients with ulnar nerve paralysis. A hand-held dynamometer was used. The results show that in ulnar nerve damage the index and long fingers have a mean metacarpophalangeal (MCP) joint flexion strength of 0.8 kg (range 0.3-1.5), compared with 6.4 kg (range 4.6-7.9) in the noninvolved hand. Thus, the damaged fingers have only about 12% of the strength of those of the noninvolved hand. In the hand with ulnar paralysis, the loss of intrinsic strength (dorsal and palmar interosseous muscles) is considerable (almost 90%). The contribution of the interosseous muscles in maintaining the intrinsic position is considerably greater than that of the lumbricals. Comparing the Medical Research Council (MRC) scale (0-5) with the dynamometry measurements shows that MRC grade 3 correlates with about 0.8 kg, while grade 5 correlates with about 6.5 kg of MCP joint flexion strength.

The hypothesis of overwork weakness in Charcot-Marie-Tooth: A critical evaluation

OBJECTIVE It has been reported that the non-dominant hand of patients with Charcot-Marie-Tooth disease is stronger than the dominant hand as a result of overwork weakness. The objective of this study was to determine if this hypothesis could be verified in our population. DESIGN Survey. SUBJECTS Twenty-eight patients with Charcot-Marie-Tooth disease type I or II from a rehabilitation department of a university hospital in the Netherlands. METHODS The strength of 3 intrinsic muscle groups of the dominant and non-dominant hand were determined using the Medical Research Council scale and the Rotterdam Intrinsic Hand Myometer. Furthermore, grip strength, pinch and key grip strength were measured. RESULTS We found no differences in muscle strength for the dominant and non-dominant hand, except for a stronger key grip strength of the dominant hand in patients with Charcot-Marie-Tooth disease type II. CONCLUSION In our population, the dominant hand of patients with Charcot-Marie-Tooth disease type I and II was equally strong as the non-dominant hand, suggesting that there is no presence of overwork weakness in the dominant hand in our group of patients. This implies that patients with Charcot-Marie-Tooth disease do not have to limit the use of their hands in daily life in order to prevent muscle strength loss.