Xavier De Boissezon

Induction of Cortical Plastic Changes in Wrist Muscles by Paired Associative Stimulation in the Recovery Phase of Stroke Patients

Background. Paired associative stimulation (PAS) combining peripheral nerve and transcranial magnetic stimulation (TMS) have been proposed to induce long-term changes in excitability of the cerebral cortex and potentially optimize motor recovery in stroke patients. Objective. This pilot study examined whether short-lasting changes in cortical excitability could be induced by a single session of PAS within the first months after stroke. Methods. Six hemiparetic patients with a subcortical stroke were included. The single session PAS protocol was applied at 1, 5, and 12 months after stroke. During the follow-up, the clinical recovery of wrist function was assessed in parallel to the PAS study by the Fugl-Meyer motor scale and dynamometry of wrist extension. Results. The PAS protocol induced a significant extensor carpi radialis motor evoked potential facilitation (mean +78.5%) on the paretic side 5 months after stroke. The facilitation was still present 12 months after stroke but on average smaller (+30 %). Conclusions. These electrophysiological findings suggest that patients with subcortical infarcts may respond to PAS in an earlier than later period after stroke. If the clinical efficacy of interventions such as PAS is confirmed, it could be proposed early as add-on therapy to optimize training-induced plasticity processes.

Sacral neuromodulation for treating neurogenic bladder dysfunction: clinical and urodynamic study.

The efficacy of sacral neuromodulation for treating refractory idiopathic lower urinary tract dysfunction is now well established. Nevertheless, results of this technique in neurological patients are still controversial. The aim of this retrospective study was to assess the results of sacral neuromodulation in neurogenic bladder dysfunction.

Prospective study of the impact on quality of life of cystectomy with ileal conduit urinary diversion for neurogenic bladder dysfunction.

Neurogenic bladder dysfunction has a negative impact on the patients quality of life (QoL). Cystectomy with ileal conduit urinary diversion is a treatment option in patients in failure after conservative management. The objective of this study was to evaluate the impact of ileal conduit urinary diversion on the QoL of patients with neurogenic bladder dysfunction.

Urinary complications and risk factors in symptomatic multiple sclerosis patients. Study of a cohort of 328 patients

Lower urinary tract dysfunctions (LUTD) are very common in Multiple Sclerosis (MS), have a significant social impact, while the organic impact is discussed. We studied urinary complications and their risk factors in our cohort of MS patients, in order to improve the management of LUTD in MS.

Cystectomie laparoscopique et urétérostomie transiléale pour troubles vésico-sphinctériens d’origine neurologique. Evaluation de la morbidité

Resume Objectifs Evaluer la morbidite et la mortalite de la cystectomie laparoscopique associee a une ureterostomie transileale pour traiter les troubles vesico-sphincteriens d’origine neurologiques. Materiel Etude prospective realisee entre fevrier 2004 et avril 2006, aupres de 26 patients consecutifs, d’âge moyen 55,0 ± 12,7 ans, ayant beneficie d’une cystectomie laparoscopique pour des troubles vesicosphincteriens d’origine neurologique. La pathologie neurologique etait une Sclerose en Plaques (SEP) dans 20 cas, un traumatisme medullaire dans 4 cas et une myelite transverse dans 2 cas. Le score ASA median preoperatoire etait de 3 (2-3). Resultats Aucune conversion n’a ete necessaire. Une complication per-operatoire a ete notee (plaie vasculaire). Aucun deces peri-operatoire n’a ete constate. La sonde naso-gastrique a ete maintenue en post-operatoire en moyenne 8,69 ± 5,9 heures. Le delai moyen de reprise de boissons etait de 1,4 ± 0,7 jours et celui de reprise de l’alimentation de 2,6 ± 1,0 jours. Le delai moyen de reprise du transit etait de 3,8 ± 3,2 jours. La duree moyenne d’hospitalisation en unite de soins intensifs etait de 3,9 ± 1,1 jours. Deux complications postoperatoires ont ete notees chez le meme patient (un ileus et un encombrement bronchique). La prise post-operatoire de morphi-niques a ete necessaire dans 60% des cas. La duree moyenne d’hospitalisation etait de 10,3 ± 4,1 jours. Deux complications post-operatoires tardives ont ete notees chez la meme patiente (deux pyelonephrites). Conclusion La cystectomie laparoscopique chez les patients neurologiques est peu morbide, permettant une realimentation precoce des patients et une duree d’hospitalisation moderee.

Proper name anomia with preserved lexical and semantic knowledge after left anterior temporal lesion: a two-way convergence defect.

This article describes the case of a patient who, following herpes simplex encephalitis (HSE), retained the ability to access rich conceptual semantic information for familiar people whom he was no longer able to name. Moreover, this patient presented the very rare combination of name production and name comprehension deficits for different categories of proper names (persons and acronyms). Indeed, besides his difficulty to retrieve proper names, SL presented a severe deficit in understanding and identifying them. However, he was still able to recognize proper names on familiarity decision, demonstrating that name forms themselves were intact. We interpret SLs deficit as a rare form of two-way lexico-semantic disconnection, in which intact lexical knowledge is disconnected from semantic knowledge and face units. We suggest that this disconnection reflects the role of the left anterior temporal lobe in binding together different types of knowledge and supports the classical convergence-zones framework (e.g., Damasio, 1989) rather than the amodal semantic hub theory (e.g., Patterson, Nestor, & Rogers, 2007).

N270 sensitivity to conflict strength and working memory: A combined ERP and sLORETA study

The event-related potential N270 component is known to be an electrophysiological marker of the supramodal conflict processing. However little is know about the factors that may modulate its amplitude. In particular, among all studies that have investigated the N270, little or no control of the conflict strength and of the load in working memory have been done leaving a lack in the understanding of this component. We designed a spatial audiovisual conflict task with simultaneous target and cross-modal distractor to evaluate the N270 sensitivity to the conflict strength (i.e., visual target with auditory distractor or auditory target with visual distractor) and the load in working memory (goal task maintenance with frequent change in the target modality). In a first session, participants had to focus on one modality for the target position to be considered (left-hand or right-hand) while the distractor could be at the same side (compatible) or at opposite side (incompatible). In a second session, we used the same set of stimuli as in the first session with an additional distinct auditory signal that clued the participants to frequently switch between the auditory and the visual targets. We found that (1) reaction times and N270 amplitudes for conflicting situations were larger within the auditory target condition compared to the visual one, (2) the increase in target maintenance effort led to equivalent increase of both reaction times and N270 amplitudes within all conditions and (3) the right dorsolateral prefrontal cortex current density was higher for both conflicting and active maintenance of the target situations. These results provide new evidence that the N270 component is an electrophysiological marker of the supramodal conflict processing that is sensitive to the conflict strength and that conflict processing and active maintenance of the task goal are two functions of a common executive attention system.

Validation of French upper limb Erasmus modified Nottingham Sensory Assessment in stroke

BACKGROUND Somatosensory impairment of the upper limb (UL) occurs in approximately 50% of adults post-stroke, associated with loss of hand motor function, activity and participation. Measurement of UL sensory impairment is a component of rehabilitation contributing to the selection of sensorimotor techniques optimizing recovery and providing a prognostic estimate of UL function. To date, no standardized official French version of a measure of somatosensory impairment has been established. OBJECTIVE To develop and validate a French version of the Erasmus modified Nottingham Sensory Assessment somatosensory (EmNSA-SS) and stereognosis (EmNSA-ST) component for evaluating the UL among adults with stroke. METHODS This study is a single-center observational cross-sectional study. A French version of the EmNSA for UL was developed by forward-backward translation and cross-cultural adaptation. Fifty stroke patients were recruited to establish concurrent-criterion-related validity, internal consistency, intra- and inter-rater reproducibility with intracorrelation coefficients (ICCs) for reliability and the minimal detectable change with 95% confidence interval (MDC95) for agreement, as well as ceiling and floor effects. Criterion validity was assessed against the Fugl-Meyer Assessment-Sensory (FMA-S) for the UL. RESULTS The median (range) EmNSA-SS score was 41.5 (1-44). The Spearman rank correlation coefficient between EmNSA-SS and FMA-S total scores was moderate (rho=0.74, P<0.001). The EmNSA-SS/ST internal consistency was adequate across subscales; with Cronbach α ranging from 0.82-0.96. For the EmNSA-SS total score, intra- and inter-rater reliability was excellent (ICC=0.92 in both cases), with MDC95 of 12.3 and 14.6, respectively. EmNSA-SS/ST total scores demonstrated no ceiling or floor effects. CONCLUSIONS The French EmNSA is a valid and reproducible scale that can be used for comprehensive and accurate assessment of somatosensory modalities in adults post-stroke. Taking less than 30min to administer, the instrument has clinical utility for use in patients with cognitive comorbidities and at various stages of recovery in multidisciplinary clinical practice and research settings.

Assessment of a program to encourage the multidisciplinary management of urinary disorders in multiple sclerosis

Urinary disorders (UD) secondary to multiple sclerosis (MS) are common and can be responsible for complications. Since 2004, we organized in our region their management through a neuro‐urological activity and a care network that established and distributed an algorithm for screening and first line care. The objective was to assess the effects of this organization on the management of UD and its impact for patients.

Action, observation or imitation of virtual hand movement affect differently regions of the mirror neuron system and the default mode network

Virtual reality (VR)-based paradigms use visual stimuli that can modulate visuo-motor networks leading to the stimulation of brain circuits. The aims of this study were to compare the changes in blood-oxygenation level dependent (BOLD) signal when watching and imitating moving real (RH) and virtual hands (VH) in 11 healthy participants (HP). No differences were found between the observation of RH or VH making this VR-based experiment a promising tool for rehabilitation protocols. VH-imitation involved more the ventral premotor cortex (vPMC) as part of the mirror neuron system (MNS) compared to execution and VH-observation conditions. The dorsal-anterior Precuneus (da-Pcu) as part of the Precuneus/posterior Cingulate Cortex (Pcu/pCC) complex, a key node of the Default Mode Network (DMN), was also less deactivated and therefore more involved. These results may reflect the dual visuo-motor roles for the vPMC and the implication of the da-Pcu in the reallocation of attentional and neural resources for bimodal task management. The ventral Pcu/pCC was deactivated regardless of the condition confirming its role in self-reference processes. Imitation of VH stimuli can then modulate the activation of specific areas including those belonging to the MNS and the DMN.