Annemieke J. Videler

Motor axon loss is associated with hand dysfunction in Charcot-Marie-Tooth disease 1a

Background: Charcot Marie Tooth type 1a (CMT1a) is a primarily demyelinating neuropathy, characterized by slowly progressive muscle weakness, atrophy, and sensory loss, and is most pronounced in both feet and hands. There is increasing evidence that muscle weakness is determined by motor axonal dysfunction. Objective: To investigate in patients with CMT1a whether motor axon loss, as estimated with motor unit number estimation (MUNE) and compound muscle action potential (CMAP), is related to hand function and manual dexterity. Methods: Hand function, manual dexterity, and axon loss were studied in 48 patients with proven CMT1a. Using high-density surface EMG on the thenar muscles, MUNE was determined and CMAPs were measured. Results: Pinch strength, clawing of the fingers, and manual dexterity correlated significantly with MUNE and CMAP (amplitude and area), while sensory impairments did not. Grip strength correlated significantly with CMAP amplitude but did not become significant with MUNE and CMAP area. Neurophysiologic variables were particularly associated with fine motor function of the hand. Conclusions: Motor axon loss is likely to be the major cause of hand dysfunction and impaired manual dexterity in Charcot Marie Tooth type 1a (CMT1a). In a clinical setting, the evaluation of the hands of patients with CMT1a should thus be mainly directed toward the evaluation of fine motor functions.

LIMITED UPPER LIMB FUNCTIONING HAS IMPACT ON RESTRICTIONS IN PARTICIPATION AND AUTONOMY OF PATIENTS WITH HEREDITARY MOTOR AND SENSORY NEUROPATHY 1A

OBJECTIVE To evaluate upper limb functioning, restrictions on participation and the independent contribution of upper and lower limb disability to participation in hereditary motor and sensory neuropathy 1a. DESIGN Descriptive cross-sectional study. SUBJECTS Forty-nine patients with hereditary motor and sensory neuropathy 1a. METHODS Perceived upper limb functioning was evaluated using the Michigan Hand Outcomes Questionnaire and participation restrictions with the Impact on Participation and Autonomy Questionnaire. Upper and lower limb domains of Guys Neurological Disability Scale were used to determine their impact on participation restrictions. RESULTS Limitations in upper limb functioning were perceived by 98% of the patients. Median scores ranged between 70 points for overall hand function and 100 points for aesthetics (scale 0-100). Patients were least satisfied with dominant hand performance. Most patients (46-78%) reported their participation to be sufficient. Restrictions were reported in the domains work, family roles, and autonomy outdoors. Minor problems with restricted participation were indicated by 22-55%, severe problems by 2-12%. Upper limb functioning correlated significantly with all participation subscales. Upper limb disability was independently associated with participation restrictions, whereas lower limb disability was not. CONCLUSION Limitations in upper limb functioning were perceived by the majority of patients with hereditary motor and sensory neuropathy 1a and strongly related to restricted participation.

Manual dexterity and related functional limitations in Hereditary Motor and Sensory Neuropathy. An explorative study

Purpose. To explore impairments in manual dexterity and perceived limitations in upper extremity-related activities in subjects with Hereditary Motor and Sensory Neuropathy (HMSN). Method. Cross-sectional study of 20 HMSN subjects. Manual dexterity was assessed using the Jebsen test of hand function. Perceived limitations were assessed using the Rehabilitation Activities Profile (RAP) and the Disabilities of Arm, Shoulder and Hand questionnaire (DASH). Results. Impaired manual dexterity was found in four out of seven Jebsen sub-tests. Turning over cards, lifting large light and large heavy objects were most impaired, as reflected by median z scores of 5.7, 12.0 and 16.9, respectively. Perceived limitations, as reflected by median and percentile (P25; P75) sum-scores, were 7.5 (3; 11.7) for the RAP domains of personal care (scale 0 – 69) and 6.0 (1.25; 15.5) for the domains of occupation (scale 0 – 42). The median (P25; P75) DASH score (scale 0 – 100) was 13.3 (2.7; 48.1). Jebsen test scores were significantly associated with RAP and DASH scores. Conclusions. Manual dexterity of HMSN subjects, especially requiring the manipulation of flat and of large objects, was impaired and associated with the amount of perceived limitations in upper extremity function. Major limitations were perceived in activities related to upper extremity function by 25% of HMSN subjects. Measurement of manual dexterity and perceived limitations should be incorporated into the evaluation and treatment of HMSN subjects.

A THUMB OPPOSITION SPLINT TO IMPROVE MANUAL DEXTERITY AND UPPER-LIMB FUNCTIONING IN CHARCOT-MARIE-TOOTH DISEASE

OBJECTIVE To assess initial efficacy and tolerability of a thumb opposition splint on manual dexterity, perceived upper limb functioning and occupational performance in patients with Charcot-Marie-Tooth disease. DESIGN One group pre-post design. PATIENTS AND METHODS Thirteen patients were provided with a neoprene opposition splint for their dominant hand. Manual dexterity (Sollerman hand function test), perceived upper limb functioning (Michigan Hand Outcomes Questionnaire) and occupational performance (Canadian Occupational Performance Measure) were assessed after using the splint and compared with pre-treatment scores (paired t-tests). Usability and tolerability were assessed with a questionnaire. RESULTS Sollerman test scores improved significantly from a mean of 47 (standard deviation (SD) 11) to 52 (SD 12) points (norm 80 points) (p = 0.006). Perceived functioning in the domain activities of daily living (scale 0-100) improved significantly from 51 (SD 20) to 60 (SD 17) points (p = 0.04). Both occupational performance and satisfaction scores improved significantly (p = 0.020). Efficacy did not relate to age, disease duration or severity. Subjects were satisfied with splint cosmesis and comfort. CONCLUSION These results indicate that a thumb opposition splint can be applied effectively to improve upper limb functioning in patients with Charcot-Marie-Tooth disease.

Tripod pinch strength and thumb opposition are the major determinants of manual dexterity in Charcot–Marie–Tooth disease type 1A

Background Clinical features of Charcot–Marie–Tooth disease type 1A (CMT1A) include slowly progressive distal muscle weakness, atrophy and sensory loss. Upper-limb involvement results in reduced manual dexterity interfering with the execution of daily activities. Objective To identify which hand function impairments are determinants of manual dexterity in CMT1A. Methods In a cross-sectional, observational study, hand function (strength, mobility and sensory function) and manual dexterity (Sollerman hand function test) were evaluated in adults with CMT1A. Multiple linear regression analysis was used to determine the independent contribution of hand function variables on manual dexterity. Multifocal motor neuropathy (MMN) patients were chosen as a reference group with only motor impairments. Results Forty-nine proven CMT1A patients (21 males, mean age 47±12) and 15 MMN patients (12 males, mean age 54±8) were studied. Hand strength, mobility and sensory functions were impaired in CMT1A compared with normal values. Limited manual dexterity was found in 94% of the CMT1A patients. From the investigated determinants (age, gender, grip and pinch strength, joint mobility, thumb opposition, touch, discrimination and vibration sense), tripod pinch strength, thumb opposition and, to a lesser degree, vibration sense were independently associated with manual dexterity (69% explained variance). Tripod pinch strength was also most strongly associated with manual dexterity in MMN. Conclusions Tripod pinch strength and thumb opposition are major determinants of manual dexterity in CMT1A and should therefore be the focus of intervention strategies that aim to preserve or enhance manual dexterity in CMT1A.