[Show description][Hide description] DESCRIPTION: accepté pour publication (NCCN) Summary
Somatosensory evoked potentials (SSEPs) are increasingly performed for the assessment of peripheral
neuropathies, but no practical guidelines have been established in this specific application. For this
purpose, a survey was conducted among the French-speaking practitioners having an experience of
SSEP recording in the context of peripheral neuropathies. The objectives were to determine the
relevant indication criteria and technical settings for SSEP recording in this condition. From this
survey, SSEPs appeared to be a second-line test when electroneuromyographic investigation was not
enough conclusive, providing complementary and valuable information on peripheral proximal
conduction and central conduction in the somatosensory pathways. Guidelines for a standardized
recording protocol, including the various variables to measure, are proposed. This consensus statement
is an important step in the process to recognize the value of this technique in assessing peripheral
neuropathies in clinical practice.
Keywords: diagnosis; evoked potentials; indication; parameters; peripheral neuropathies; technique.
[Show abstract][Hide abstract] ABSTRACT: Background:
Attentional resources appear to be involved in the occurrence of FoG. The Parkgait study recently reported that methylphenidate reduces gait hypokinesia and freezing of gait (FoG) in advanced PD patients receiving STN-DBS in the off-dopaminergic drug condition. Methylphenidate is considered to improve attention. The primary objective of the present ancillary study was to determine whether methylphenidate reduced the interference between a cognitive task and gait in patients with FoG. The study's secondary objective was to compare attentional performance in methylphenidate-treated and placebo-treated patients.
A total of 24 patients (from two centers) were included in the study. Patients were randomly assigned 1:1 to a three-month course of methylphenidate (1mg/kg/day) or placebo. Patients were assessed after an acute L-dopa challenge. The primary outcome criterion was the stride length ratio ((dual-task stride length minus free gait stride length)/free gait stride length). Trials with FoG episodes were excluded from the analysis. Secondary outcomes included changes in reaction times for computerized attention tasks and FoG severity.
When comparing patients receiving methylphenidate with those receiving placebo, we did not observe any significant differences in the interaction between the dual task and gait or in attentional performance.
As in the main Parkgait study, methylphenidate did not reduce gait hypokinesia in patients receiving dopaminergic treatment. Our present results suggest that the reduction in the number of FoG episodes previously observed in patients on methylphenidate was neither due to interaction between a dual-task and gait nor an increase in attentional performance.
[Show abstract][Hide abstract] ABSTRACT: Objective:
O-arm(®) now gives us the opportunity not only to perform 2D but also 3D scans during deep brain stimulation (DBS) procedures. We present our experience with the intraoperative use of this device. Our objective was to measure the geometrical accuracy of electrode placement during surgical procedures driven under O-arm(®) control.
Fifteen patients underwent STN-DBS. For the first 4 patients, 3D scans were performed at the end of the procedure. We calculated the accuracy of electrode positioning, i.e. the distance between final electrode positioning and the planned trajectory. For the next 11 patients, who underwent both intraoperative and final 3D scan, we also calculated the accuracy of the microelectrode positioning.
Average stimulation-induced improvement of UPDRS-III score was 52.5±15%. For the first 4 patients, the mean electrode positioning accuracy was 1.46±0.56mm. For the 11 patients who underwent intraoperative 3D scan, the mean microelectrodes positioning accuracy was 1.59±1.1mm. Aberrant positioning was detected in two cases, and was analyzed by fusing 3D scan with preoperative MR images. The definite electrodes positioning accuracy was 1.05±0.54mm.
Intraoperative 3D scan is feasible, and can help us detect and correct early aberrant trajectories.
[Show abstract][Hide abstract] ABSTRACT: Chorea-acanthocytosis (ChAc) is a neuroacanthocytosis syndrome presenting with severe movement disorders poorly responsive to drug therapy. Case reports suggest that bilateral deep brain stimulation (DBS) of the ventro-postero-lateral internal globus pallidus (GPi) may benefit these patients. To explore this issue, the present multicentre (n=12) retrospective study collected the short and long term outcome of 15 patients who underwent DBS.
Data were collected in a standardized way 2-6 months preoperatively, 1-5 months (early) and 6 months or more (late) after surgery at the last follow-up visit (mean follow-up: 29.5 months).
Motor severity, assessed by the Unified Huntington's Disease Rating Scale-Motor Score, UHDRS-MS), was significantly reduced at both early and late post-surgery time points (mean improvement 54.3% and 44.1%, respectively). Functional capacity (UHDRS-Functional Capacity Score) was also significantly improved at both post-surgery time points (mean 75.5% and 73.3%, respectively), whereas incapacity (UHDRS-Independence Score) improvement reached significance at early post-surgery only (mean 37.3%). Long term significant improvement of motor symptom severity (≥20 % from baseline) was observed in 61.5 % of the patients. Chorea and dystonia improved, whereas effects on dysarthria and swallowing were variable. Parkinsonism did not improve. Linear regression analysis showed that preoperative motor severity predicted motor improvement at both post-surgery time points. The most serious adverse event was device infection and cerebral abscess, and one patient died suddenly of unclear cause, 4 years after surgery.
This study shows that bilateral DBS of the GPi effectively reduces the severity of drug-resistant hyperkinetic movement disorders such as present in ChAc.
PLoS ONE 11/2013; 8(11):e79241. DOI:10.1371/journal.pone.0079241 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Obsessive-compulsive disorder (OCD) is associated with visuospatial working memory deficits. Intolerance of uncertainty is thought to be a core component of OCD symptoms. Recent findings argue for a possible relationship between abilities in visuospatial memory and uncertainty. However, this relationship remains unclear in both OCD patients and healthy subjects. To address this issue, we measured performance in visuospatial working memory and the propensity to express uncertainty during decision making. We assessed their relationship and the temporal direction of this relationship in both OCD patients and healthy subjects.
Baseline abilities in visuospatial working memory were measured with the Corsi block-tapping test. A delayed matching-to-sample task was used to identify explicit situations of certainty, uncertainty and ignorance and to assess continuous performance in visuospatial working memory. Behavioural variables were recorded over 360 consecutive trials in both groups.
Baseline scores of visuospatial working memory did not predict the number of uncertain situations in OCD patients whereas they did in healthy subjects. Uncertain trials led to reduced abilities in visuospatial working memory to 65% of usual performance in OCD patients whereas they remained stable in healthy subjects.
The present findings show an opposite temporal direction in the relationship between abilities in working memory and uncertainty in OCD patients and healthy subjects. Poor working memory performance contributes to the propensity to feel uncertainty in healthy subjects whereas uncertainty contributes to decreased continuous performance in working memory in OCD patients.
Psychological Medicine 10/2013; 44(10):1-12. DOI:10.1017/S0033291713002730 · 5.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Epileptiform discharges (ED) can occur during sevoflurane induction, especially in young female patients and when high alveolar concentrations are used. The aim of this study was to evaluate whether low sevoflurane concentration reduces the occurrence of ED in female patients.
Thirty-four female patients scheduled for minor gynecological surgery were prospectively included and randomized in two groups. In group A, anesthesia was induced with sevoflurane inspired 8% manually set via the circuit of the Zeus(®) (Dräger Medical, Lübeck, Germany) anesthesia workstation (fresh gas flow 8L.min(-1)) for 2min and then 2.5%. In group B, induction was performed by target-controlled inhalation with a target end-tidal concentration of sevoflurane set at 2.5% (fresh gas flow in auto-control mode). Electroencephalogram (EEG) was recorded in the operating room throughout induction till two min after intubation and analyzed off-line by a neurophysiologist blinded to the randomization.
ED occurred in five patients (15%): one in group A and four in group B (P>0.05). ED occurred with a median delay of 303 s [25-75 interquartiles: 135-418] and the median duration of ED episode was 13 s [3-78]. Fifteen patients had abnormal movements without simultaneous EEG abnormality.
Induction of anesthesia with low target concentration of sevoflurane (2.5%) fails to totally prevent the occurrence of ED in young female patients and should be used carefully in this population.
Annales francaises d'anesthesie et de reanimation 09/2013; 32(10). DOI:10.1016/j.annfar.2013.07.812 · 0.84 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background:
The dorso-lateral part of the subthalamic nucleus (STN) is considered as the usual target of deep brain stimulation for Parkinson's disease. Nevertheless, the exact anatomical location of the electrode contacts used for chronic stimulation is still a matter of debate. The aim of this study was to perform a systematic review of the existing literature on this issue.
We searched for studies on the anatomical location of active contacts published until December 2012.
We identified 13 studies, published between 2002 and 2010, including 260 patients and 466 electrodes. One hundred and sixty-four active contacts (35 %) were identified within the STN, 117 (25 %) at the interface between STN and the surrounding structures, 184 (40 %) above the STN and one within the substantia nigra. We observed great discrepancies between the different series. The contra-lateral improvement was between 37 and 78.5 % for contacts located within the STN, between 48.6 and 73 % outside the STN, between 65.3 and 66 % at the interface. The authors report no clear correlation between anatomical location and stimulation parameters.
Post-operative analysis of the anatomical location of active contacts is difficult, and all the methods used are debatable. The relationship between the anatomical location of active contacts and the clinical effectiveness of stimulation is unclear. It would be necessary to take into account the volume of the electrode contacts and the diffusion of the stimulation. We can nevertheless assume that the interface between dorso-lateral STN, zona incerta and Forel's fields could be directly involved in the effects of stimulation.
[Show abstract][Hide abstract] ABSTRACT: Adult-onset epilepsy is commonly thought to be secondary to a brain lesion. However, the etiology of adult-onset epilepsy remains unknown in approximately 25% of patients, despite progress in medical and diagnostic tools. In the present study, we investigated whether late-onset partial cryptogenic epilepsies could be subgrouped based on seizure semiology and clinical characteristics. A total of 41 patients with late-onset cryptogenic epilepsy were included, and the corresponding clinical and electrophysiological data were analyzed. The following three clinical subgroups were identified: 1) a group that fulfilled the diagnostic criteria of transient epileptic amnesia (TEA); 2) a group with late-onset cryptogenic epilepsies with a temporal seizure semiology; and 3) a cryptogenic extratemporal group, which was consistent with the categorization of cryptogenic epilepsies, i.e., epilepsies involving unknown lesions. The temporal group showed homogeneous clinical characteristics, especially a rapid evolution and a greater tendency toward generalization and pharmacoresistance compared with the other two groups. Transient epileptic amnesia was associated with a higher frequency of sleep disorders than either of the other groups. Our findings argue for the clinical identification of a subgroup of late-onset temporal epilepsy that might constitute an idiopathic form. The association between TEA and sleep disorders would suggest a possible pathophysiological role of sleep apnea syndromes in TEA.
[Show abstract][Hide abstract] ABSTRACT: Background: Chorea-acanthocytosis (ChAc) is a neuroacanthocytosis syndrome presenting with severe movement disorders poorly responsive to drug therapy. Case reports suggest that bilateral deep brain stimulation (DBS) of the ventro-postero-lateral internal globus pallidus (GPi) may benefit these patients. To explore this issue, the present multicentre (n=12) retrospective study collected the short and long term outcome of 15 patients who underwent DBS. Methods: Data were collected in a standardized way 2-6 months preoperatively, 1-5 months (early) and 6 months or more (late) after surgery at the last follow-up visit (mean follow-up: 29.5 months). Results: Motor severity, assessed by the Unified Huntington's Disease Rating Scale-Motor Score, UHDRS-MS), was significantly reduced at both early and late post-surgery time points (mean improvement 54.3% and 44.1%, respectively). Functional capacity (UHDRS-Functional Capacity Score) was also significantly improved at both post-surgery time points (mean 75.5% and 73.3%, respectively), whereas incapacity (UHDRS-Independence Score) improvement reached significance at early post-surgery only (mean 37.3%). Long term significant improvement of motor symptom severity (≥20 % from baseline) was observed in 61.5 % of the patients. Chorea and dystonia improved, whereas effects on dysarthria and swallowing were variable. Parkinsonism did not improve. Linear regression analysis showed that preoperative motor severity predicted motor improvement at both post-surgery time points. The most serious adverse event was device infection and cerebral abscess, and one patient died suddenly of unclear cause, 4 years after surgery. Conclusion: This study shows that bilateral DBS of the GPi effectively reduces the severity of drug-resistant hyperkinetic movement disorders such as present in ChAc. Funding: This study was supported by the ERA-net E-Rare consortium European Multidisciplinary Initiative on Neuroacanthocytosis (EMINA); www.e-rare.eu/node/474. Western blot analysis for chorein was performed with the financial support of the Neuroacanthocytosis Advocacy and the EMINA consortium (BMBF 01GM1003). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist.
[Show abstract][Hide abstract] ABSTRACT: Introduction:
Behavioral adaptation generally follows the contextual changes arising from the consequences (rewards and punishments) of an action. According to the reciprocal determinism model, there is a mutual influence between external context, cognitive processes and behavior. The maladaptive behaviors observed in obsessive-compulsive disorder (OCD) have been hypothesized to result from the disruption of the interactions between these three entities. For this, we assessed the influence of error signals and checking behavior on prefrontal cortical functions during decision-making in 14 OCD patients and 14 matched healthy participants.
We used a behavioral task designed to elicit intolerance of uncertainty (IU) followed by the free expression of checking behaviors, which was coupled with functional magnetic resonance imaging.
At the behavioral level, IU intensity was correlated to the number of checking behaviors in both checking OCD patients and healthy controls during decision-making. However, external error signals did not influence checking behaviors in OCD patients, whereas they appeared to trigger checking behaviors in healthy subjects. At the neural level, IU intensity was positively correlated with activation in the orbitofrontal cortex (OFC) in both the OCD and control groups. At the region of interest (ROI) level, error signals increased IU-related OFC activations; in contrast, checking behaviors contributed to decreasing these neural activations in the healthy subjects, but no such modulation was observed in the OCD patients.
Our results show that IU-related OFC dysfunctions are not under the influence of the context and the behavioral response in OCD, suggesting that alterations of the dynamic features for this neural network may contribute to the expression of OCD symptoms.
[Show abstract][Hide abstract] ABSTRACT: Objective:
Bispectral index (BIS) may be used in traumatic brain-injured patients (TBI) with intractable intracranial hypertension to adjust barbiturate infusion but it is obtained through a unilateral frontal electrode. The objective of this study was to evaluate differences in BIS between hemispheres in two groups: unilateral frontal (UFI) and diffuse (DI) injured.
Patients and methods:
Prospective monocenter observational study in 24 TBI treated with barbiturates: 13 UFI and 11 DI. Simultaneous BIS and EEG was recorded for 1h. Goal of monitoring was a left BIS between 5 and 15. Biases in BIS were considered as clinically relevant if greater than 5. Differences in biases were interpreted from both statistical (Mann-Whitney test) and clinical points of view.
Mean BIS in the two hemispheres remained in the same monitoring range. There were statistic and clinical differences in some values in the two groups of patients (15% of bias greater than I5I in UFI group and 10% in DI group). BIS monitoring allowed the adequate number of bursts/minutes to be predicted in 18 patients and did not detect an overdosage in 2.
While asymmetric BIS values in TBI patients occur whatever the kind of injury, they were not found to be clinically relevant in most of these heavily sedated patients. Asymmetrical BIS monitoring might be sufficient to monitor barbiturate infusion in TBI provided that the concordance between BIS and EEG is regularly checked.
Annales francaises d'anesthesie et de reanimation 11/2012; 31(12). DOI:10.1016/j.annfar.2012.09.007 · 0.84 Impact Factor