Congenital myasthenic syndromes in adults: clinical features, diagnosis and long-term prognosis.

Congenital myasthenic syndromes (CMS) are clinically and genetically heterogeneous diseases caused by mutations affecting neuromuscular transmission. Even if the first symptoms mainly occur during childhood, adult neurologists must confront this challenging diagnosis and manage these patients throughout their adulthood. However, long-term follow-up data from large cohorts of CMS patients are lacking and the long-term prognosis of these patients is largely unknown. We report the clinical features, diagnostic difficulties, and long-term prognosis of a French nationwide cohort of 235 adult patients with genetically confirmed CMS followed in 23 specialized neuromuscular centres. Data were retrospectively analysed. Of the 235 patients, 123 were female (52.3%). The diagnosis was made in adulthood in 139 patients, 110 of whom presented their first symptoms before the age of 18. Mean follow-up time between first symptoms and last visit was 34 years (SD = 15.1). Pathogenic variants were found in 19 disease-related genes. CHRNE-low expressor variants were the most common (23.8%), followed by variants in DOK7 (18.7%) and RAPSN (14%). Genotypes were clustered into four groups according to the initial presentation: ocular group (CHRNE-LE, CHRND, FCCMS), distal group (SCCMS), limb-girdle group (RAPSN, COLQ, DOK7, GMPPB, GFPT1), and a variable-phenotype group (MUSK, AGRN). The phenotypical features of CMS did not change throughout life. Only four genotypes had a proportion of patients requiring intensive care unit (ICU) admission that exceeded 20%: RAPSN (54.8%), MUSK (50%), DOK7 (38.6%) and AGRN (25.0%). In RAPSN and MUSK patients most ICU admissions occurred before age 18 years and in DOK7 and AGRN patients at or after 18 years of age. Different patterns of disease course (stability, improvement and progressive worsening) may succeed one another in the same patient throughout life, particularly in AGRN, DOK7 and COLQ. At the last visit, 55% of SCCMS and 36.3% of DOK7 patients required ventilation; 36.3% of DOK7 patients, 25% of GMPPB patients and 20% of GFPT1 patients were wheelchair-bound; most of the patients who were both wheelchair-bound and ventilated were DOK7 patients. Six patients died in this cohort. The positive impact of therapy was striking, even in severely affected patients. In conclusion, even if motor and/or respiratory deterioration could occur in patients with initially moderate disease, particularly in DOK7, SCCMS and GFPT1 patients, the long-term prognosis for most CMS patients was favourable, with neither ventilation nor wheelchair needed at last visit. CHRNE patients did not worsen during adulthood and RAPSN patients, often severely affected in early childhood, subsequently improved.

Foot Function Index: A Promising Questionnaire for Individuals With Charcot-Marie-Tooth Disease Type 1A.

OBJECTIVE: To evaluate in a preliminary methodologic study, the Foot Function Index (FFI), a 3-subscale (pain, disability, and activity restriction) foot disability assessment questionnaire, in patients with Charcot-Marie-Tooth disease type 1A (CMT1A). DESIGN: Monocentric exploratory cross-sectional study with 2 identical evaluations by the same physical medicine and rehabilitation physician at 14-day intervals (test-retest) according to international guidelines for validating health-related patient-reported outcomes, the Consensus-based Standards for the Selection of Health Measurement Instruments Criteria. SETTING: Physical medicine and rehabilitation and neurology departments in a French academic hospital. PARTICIPANTS: Patients with CMT1A confirmed by molecular biology (N=26). INTERVENTION: The FFI and a health-related quality-of-life questionnaire (Medical Outcomes Study Short Form 36 [SF-36] with mental and physical composite scores) combined with quantitative walk analysis by instrumental gait analysis and evaluation of isokinetic quadriceps and hamstrings peak torque by isokinetic dynamometer. MAIN OUTCOME MEASURES: FFI score and its dimensions. RESULTS: Acceptability was satisfactory, with less than 5% missing data and good distribution of results. Internal consistency was very satisfactory, with Cronbach α of 0.95. Reproducibility was very satisfactory, with Lin concordance coefficient 0.82. External consistency was satisfactory, with expected correlation coefficients: the FFI was significantly correlated with the SF-36 physical composite score and gait parameters (cadence) (r=-0.58 and r=-0.52; P<.005) but not with peak torque or SF-36 mental composite score. CONCLUSIONS: This study confirms the very good metrologic properties of the FFI in patients with CMT1A. The FFI could be a promising questionnaire to assess foot-related disability in a neurologic disease. Complementary studies are still needed to confirm these promising preliminary results.

Is there pain with neuropathic characteristics in patients with amyotrophic lateral sclerosis? A cross-sectional study.

BACKGROUND: Amyotrophic lateral sclerosis is a progressive debilitating and lethal disorder, characterized by degeneration of motor neurons that warrant palliative care. Pain is frequent in patients with amyotrophic lateral sclerosis and significantly impacts on quality of life. AIM: To describe pain and assess the prevalence of pain with neuropathic characteristics in patients with amyotrophic lateral sclerosis. DESIGN: Cross-sectional survey from March 2009 to October 2013. SETTING/PARTICIPANTS: Amyotrophic lateral sclerosis patients underwent multidisciplinary assessment and completed questionnaires measuring the severity and impact of pain and anxiety. The Douleur Neuropathique-4 questionnaire was used to look for pain with neuropathic characteristics. RESULTS: Of 96 clinical evaluations, 93 were usable for analysis (age at onset: 62 ± 12.5 years; disease duration: 34 ± 33 months). The overall pain prevalence was 66%, with 9% experiencing pain with neuropathic characteristics. Pain was most often located in the neck and shoulders (38% of pain patients). Neck and shoulder pain was associated with neck (p = 0.04) and proximal upper limb muscular weakness (p = 0.02), respectively. Pain was not associated with disease duration, respiratory or nutritional parameters, but with higher anxiety scores (p = 0.01). Patients with neuropathic characteristics pain did not differ significantly from patients with or without pain, except that they had higher minimal pain intensity score (p < 0.05). Neuropathic characteristics pain was frequently spontaneous (rarely evoked) and described as numbness, burning, electric shock, tingling, and pins-and-needle. CONCLUSION: Even if amyotrophic lateral sclerosis is a disease of the motor system, pain is frequent and can rarely have neuropathic characteristics. Pain must be always sought and appropriately treated to limit quality of life impairment.

Multidimensional evaluation is necessary to assess hand function in patients with Charcot-Marie-Tooth disease type 1A.

BACKGROUND: Charcot-Marie-Tooth (CMT) disease type 1A (CMT1A) is the most common hereditary neuropathy. Several studies have assessed the relation between axonal loss and grip strength; however, the functional impact on dexterity and health-related quality of life (HRQoL) is unknown. We hypothesized that the severity of axonal loss will be correlated with loss of function and HRQoL. OBJECTIVE: The purpose of this study was to evaluate the relation between severity of electroneuromyography impairment and its impact on function and HRQoL in adults with CMT1A. METHODS: Grip and lateral pinch strength were evaluated with specific dynamometers: the Jamar and the Pinch Gauge. Dexterity was explored with the Sollerman, Jebsen, and Nine-hole Peg tests. The CMT impact on well-being was assessed by the validated Medical Outcomes Study Short Form 36 (SF-36), Beck Depression Inventory, and Fatigue Severity Scale, and disease severity by the CMT neuropathy score and Inflammatory Neuropathy Cause and Treatment sensory sum score. Finally, axonal loss and demyelination process was assessed by electroneuromyography. RESULTS: We included 33 participants with CMT1A (23 females, mean [SD] age 47.0 [4.7] years). We found lack of correlation between severe electroneuromyography impairment (frequency of abnormal results >80%), significant distal amyotrophy (70%) and quality of life (mean [SD] scores for physical and mental SF-36 36.4 [10.0] and 48.4 [11.5]), autonomy for activities of daily living, and hand function that remains relatively preserved. We found a correlation between lateral pinch and dexterity according to the Sollerman test (r=0.52, p<0.05) but a lack of correlation among the other parameters. CONCLUSIONS: Electrophysiological follow-up seems to be of little relevance to follow HRQoL in individuals with CMT1A and manual function related to functional objectives for everyday physical medicine and rehabilitation practice. The manual function is complex and requires an overall, quantitative, qualitative and multidisciplinary assessment. Each tool (Pinch Gauge, Jamar, Sollerman, Jebsen, Nine-hole Peg) measures a specific element of manual function and is necessary when performing a grip function analysis.

Walking Speed Is Correlated With the Isokinetic Muscular Strength of the Knee in Patients With Charcot-Marie-Tooth Type 1A.

Charcot-Marie-Tooth disease type 1A is the most common hereditary neuropathy. Affected individuals have a distal motor deficit, initially affecting the lower limbs and impairing walking performance. Isokinetic dynamometry can be used to objectively assess muscle strength of patients with neuromuscular disorders. No studies have evaluated the effect of muscle strength deficits of knee extensors and flexors on walking parameters for patients with Charcot-Marie-Tooth disease type 1A. The purpose of this study was to determine correlations between the isokinetic muscular strength of knee flexors and knee extensors and walk parameters for patients with Charcot-Marie-Tooth disease type 1A. isokinetic muscular strength of the knee was assessed on an isokinetic dynamometer (Cybex) and walking by instrumented walkway analysis (GaitRite). We included 33 patients (23 females, mean ± SD age 46.7 ± 13.3 yrs, mean ± SD body mass index 25.7 ± 4.6 kg/m). We found a correlation between walking speed and isokinetic muscular strength of knee extensors for the entire population and between walking speed and isokinetic muscular strength of knee extensors and knee flexors for patients younger than 50 yrs. Isokinetic dynamometry can provide objective measures of knee muscle strength, which is correlated with walking speed but not cadence or step/stride length of patients with Charcot-Marie-Tooth disease.