Manual dexterity in hereditary motor and sensory neuropathy type 1a: severity of limitations and feasibility and reliability of two assessment instruments.

OBJECTIVE To assess the prevalence and significance of impaired manual dexterity in hereditary motor and sensory neuropathy type 1a (HMSN 1a), with the Sollerman hand function and the Functional Dexterity test, and compare the reliability and agreement of the tests. DESIGN Descriptive cross-sectional study. SUBJECTS Forty-nine subjects with HMSN 1a. RESULTS Forty-six (94%) subjects had an abnormal Sollerman sum score (< 80) for the dominant hand. The most difficult subtests required finger grips such as pulp, tripod and lateral pinches. Dexterity scores of both hands were categorized as "moderately functional". Test-retest reliability was excellent for the Sollerman test, with intraclass correlation coefficients between 0.98 and 0.99 (95% confidence interval (CI) 0.97-0.99), and good for Functional Dexterity test scores with correlation coefficients between 0.83 and 0.95 (95% CI. 71-0.97). The 95% limits of agreement between Sollerman tests showed that differences greater than 3 points can be interpreted as a change in dexterity. The Functional Dexterity test limits were wide. CONCLUSION Impaired manual dexterity is common among subjects with HMSN 1a, stressing that the evaluation of dexterity is an essential element of the functional assessment. Both tests are able to detect impaired manual performance in HMSN 1a. For monitoring of disease progression and the effects of treatment programmes the Sollerman test is most suitable.