Diffuse brain connectivity changes in Charcot-Marie-Tooth type 1a patients: a resting-state functional magnetic resonance imaging study.

BACKGROUND AND PURPOSE: Changes of brain structure and function have been described in peripheral neuropathies. The aim of our study was to systematically investigate possible modifications of major large-scale brain networks using resting-state functional magnetic resonance imaging (RS-fMRI) in Charcot-Marie-Tooth disease type 1A (CMT1A) patients. METHODS: In this cross-sectional study, 3-T MRI brain scans were acquired of right-handed genetically confirmed CMT1A patients and age- and sex-comparable healthy controls. Patients also underwent clinical and electrophysiological examinations assessing neurological impairment. RS-fMRI data were analysed using a seed-based approach, with 32 different seeds sampling the main hubs of default mode, sensorimotor, visual, salience (SN), dorsal attention, frontoparietal, language and cerebellar networks. Between-group differences in terms of functional connectivity (FC) with the explored seeds were tested voxelwise, correcting for local grey matter density to account for possible structural abnormalities, whilst the relationship between FC modifications and neurological impairment was investigated using robust correlation analyses. RESULTS: Eighteen CMT1A patients (34.0 ± 11.4 years; M/F 11/7) were enrolled, along with 20 healthy controls (30.1 ± 10.2 years; M/F 11/9). In the CMT group compared to controls, clusters of increased FC with the visual cortex (P = 0.001), SN (P < 6 × 10-4 ), dorsal attention network (P < 8 × 10-5 ) and language network (P < 7 × 10-4 ) were found, along with a single cluster of reduced FC with the visual cortex in the left lentiform nucleus (P = 10-6 ). A significant correlation emerged between neurophysiological impairment and increased FC with right temporal language areas (r = 0.655, P = 0.006), along with an association between walking ability and increased FC with the left supramarginal gyrus (SN) (r = 0.620, P = 0.006). CONCLUSIONS: Our data show evidence of diffuse functional reorganization involving multiple large-scale networks in the CMT1A brain, independent of structural modifications and partially correlating with peripheral nerve damage and functional impairment.

Motor performance deterioration accelerates after 50 years of age in Charcot-Marie-Tooth type 1A patients.

BACKGROUND AND PURPOSE: The aim of our study was to describe, by a case-control and cross-sectional design, the correlation between clinical impairment and age in Charcot-Marie-Tooth type 1A (CMT1A) patients. METHODS: Seventy CMT1A patients and 70 sex- and age-matched healthy controls were enrolled. Motor performance was assessed through the 10-m walk test, the 6-min walk test and the 9-hole peg test of the dominant and non-dominant side, and muscle strength was measured by using the Medical Research Council score. In the CMT1A group, disability and quality of life were evaluated using the Charcot-Marie-Tooth Neuropathy Score (CMTNS) and the Short Form 36 (SF-36) questionnaire. Cross-sectional relationships between age and all clinical measures were analyzed and differences in the slopes between cases and controls were calculated. The occurrence of a structural change in the age-related progression of clinical measures was explored. RESULTS: The deterioration of motor performance correlated with age in both groups with a greater slope in CMT1A patients than controls. The deterioration of CMTNS and SF-36 correlated with age in the CMT1A group. The deterioration of all clinical measures with the exception of the SF-36 questionnaire showed a structural change at the 50th year of age. The rate of deterioration was no different between patients and controls until 50 years of age, whereupon it became significantly greater in CMT1A patients. CONCLUSION: Our study supports that the disease progression in CMT1A patients is an age-related process and the 50th year of age represents a critical moment after which the clinical decline becomes faster.

Multimodal evoked potentials follow up in multiple sclerosis patients under fingolimod therapy.

BACKGROUND: Clinical trials have shown the therapeutic effect of fingolimod in reducing disease activity in relapsing-remitting multiple sclerosis (RR-MS), but its influence on nervous conduction assessed by evoked potentials (EPs) has not been previously investigated. METHODS: EP data of 20 patients examined 12months prior to initiation of fingolimod (t=-1), at treatment initiation (t=0) and 1year later (t=+1) were compared. Each EP (VEP, MEP, SEP) and EP sum score, a global evoked potential score as the sum score of the each EP score was evaluated and correlated with Expanded Disability Status Scale (EDSS). RESULTS: During pre-treatment period (1year) EDSS worsened while one year after fingolimod treatment EDSS remained stable. From t-1 to t0 VEP, SEP, MEP and EP sum score worsened while from t0 to t+1 VEP, SEP and EP sum score improved, and MEP score remain stable. VEP and SEP were related to EDSS at baseline (t=-1), while MEP and total EP sum score were related to EDSS at all time points. CONCLUSION: Fingolimod is able to improve visual and somatosensory evoked potential in RR-MS patients even if clinical disability scale remains stable. VEP and SEP could give eloquent information on pathway underweighted in EDSS. EPs are useful to evaluate fingolimod effects in clinical practice.

Spasmodic dysphonia follow-up with videolaryngoscopy and voice spectrography during treatment with botulinum toxin.

Spasmodic dysphonia (SD) is a focal dystonia of laryngeal muscles seriously impairing quality of voice. Adductor SD (ADSD) is the most common presentation of this disorder that can be identified by specialized phoniatricians and neurologists firstly on a clinical evaluation and then confirmed by videolaryngoscopy (VL). Botulinum toxin (BTX) injection with electromyographic guidance in muscles around vocal cords is the most effective treatment. Voice Handicap Index (VHI) questionnaire is the main tool to assess dysphonia and response to treatment. Objective of this study is to perform VL and voice spectrography (VS) to confirm the efficacy of BTX injections over time. 13 patients with ADSD were studied with VHI, VL and VS before and after 4 consecutive treatment with onobotulinumtoxin-A. For each treatment vocal improvement was proved by a significant reduction of VHI score and increase of maximum time phonation and harmonic-to-noise ratio while VL showed the absence of spasm in most of patients. No change of the response to BTX was found between injections. This study supports the efficacy of the treatment of SD with BTX with objective measurements and suggests that the efficacy of recurring treatments is stable over time.

The combined treatment with orbital and pretarsal botulinum toxin injections in the management of poorly responsive blepharospasm.

Blepharospasm (BS) is a focal dystonia involving involuntary contractions of muscles around the eyes. Botulinum toxin (BoNT) is the most effective treatment for BS and the technique of injection changes depending on the clinical picture. Usually typical BS benefits from the injection in the orbital part of the orbicularis oculi (OOc) muscle (orbital injection), while BoNT injection in the pretarsal part of OOc muscle is helpful especially for the atypical BS (opening eyelid apraxia). The aim of this study was to compare the efficacy of two injection techniques, the orbital versus the combined (injection in both orbital and pretarsal part of OOc) in BS patients with unsatisfactory response to BoNT. Nineteen patients with typical BS not having a satisfactory response from BoNT treatment with the orbital injection (primary and secondary resistant patients) were studied. After 3 months from the last orbital injection patients received the combined injection; they were assessed with the JRS and BSDI scales after 4 weeks from the last orbital and the first combined injection. Statistical analysis showed a significant reduction (p < 0.05) of the mean score of JRS and BSDI scales comparing the combined with orbital injection. This study shows that the treatment of typical BS can have better results when BoNT is injected with the combined technique in primary and secondary resistant patients.

The effects of prolonged cathodal direct current stimulation on the excitatory and inhibitory circuits of the ipsilateral and contralateral motor cortex.

Weak cathodal transcranial direct current stimulation (tDCS) of the human hand area modulates corticospinal excitability with a suppression of motor-evoked potentials (MEPs) evoked by transcranial magnetic stimulation (TMS). The changes in excitability persist beyond the time of stimulation if tDCS is given for several minutes and can remain stable for an hour or more. The aim of present study was to evaluate whether a long-lasting suppression of cortical excitability could be induced by prolonged cathodal tDCS (20 min of stimulation). We also explored the impact of brain-derived neurotrophic factor (BDNF) gene polymorphisms, on tDCS after-effects. Cortical excitability to single and paired-pulse TMS was evaluated both for the stimulated and contralateral hemisphere, before and up to 24 h after 20 min of cathodal tDCS. We evaluated threshold and amplitude of MEPs, short interval intracortical inhibition (SICI), and intracortical facilitation (ICF). tDCS produced a pronounced suppression of MEP amplitude that was still significant at 3 h after the end of stimulation. The BDNF genotype had not influence on tDCS after-effects. Thresholds for MEPs, SICI and ICF were not affected. No significant effect was observed in the contralateral hemisphere. Twenty minutes of cathodal tDCS is capable of inducing a long-lasting suppression of the excitability of the human motor cortex.