[A case of neuropathy mimicking Guillain-Barré syndrome after arsenic intoxication]. / Un cas de neuropathie mimant un syndrome de Guillain-Barré après une intoxication à l'arsenic.

INTRODUCTION: Chronic arsenic toxicity is a global health problem affecting millions of people. Acute arsenic poisoning is less frequent and it is most often lethal. Therefore, its consequences are not well known, more precisely its neurological consequences. OBSERVATION: We report a case of Guillain-Barré-like syndrome and encephalopathy after acute arsenical poisoning in a 50 year-old man. After 4 month follow-up, the improvement was slow and limited with persistent motor and proprioceptive deficits. DISCUSSION: The most frequent neurological complication induced by acute arsenical poisoning is a distal, symmetrical, sensory, axonal polyneuropathy. Yet the clinical course and the electrophysiological findings may also suggest a Guillain-Barré like syndrome. Moreover, the chelating is not very effective on the neurological complications. CONCLUSION: Any discrepancies in the clinical course of a Guillain-Barré syndrome shall lead to reconsider the diagnosis. The association of gastro-intestinal disorders, skin lesions, and encephalopathy and mood disorders leads to discuss intoxication with heavy metal and more precisely with arsenic. Moreover, the chelating is not very effective on the neurological complications.

Stimulation of the subthalamic nucleus in Parkinson's disease: cognitive and affective changes are not linked to the motor outcome.

BACKGROUND: Subthalamic nucleus deep brain stimulation (STN0 DBS) is a widely performed surgical treatment in PD. However, the relationship between motor results and cognitive/behavioural modifications is unclear. OBJECTIVE: This study investigated the correlation patterns of the motor, cognitive and behavioural consequences of STN DBS with respect to positioning of the active contact. METHODS: Fifty-eight consecutive PD patients having undergone STN DBS were assessed pre-operatively and 12 months after surgery. RESULTS: Motor, cognitive and behavioural results were neither correlated to each other nor linked to the position of the active contact. Three patients with a history of pre-operative, dopaminergic psychosis or post-surgical confusion became demented. Age and a distant history of depression were associated with the occurrence of post-surgical depression. CONCLUSION: Correct screening of patients for STN DBS remains an important issue, since the current implantation procedure is not able to take account of potential functional heterogeneity within the target.

Disturbance of sensory filtering in dementia with Lewy bodies: comparison with Parkinson's disease dementia and Alzheimer's disease.

INTRODUCTION: Prepulse inhibition (PPI) is considered to mirror an organism's ability to filter out irrelevant sensory or cognitive information. The disruption of PPI has never been studied in individuals suffering from dementia with Lewy bodies (DLB). As attention deficits largely contribute to cognitive impairment in DLB, an investigation with a PPI paradigm is useful for differential diagnosis of DLB versus Alzheimer's disease (AD) and Parkinson's disease dementia (PDD). OBJECTIVE AND METHODS: PPI of the N1/P2 component of auditory evoked potentials was used to investigate the early stages of attention selectivity in 10 DLB, 10 AD, and 10 PDD patients, as well as in 10 healthy controls. The PPI paradigm consisted of the presentation of sound pulses (40 ms, 115 dB) preceded by a prepulse (40 ms, 80 dB). Sound stimuli were presented in a total of 80 trials in a pseudo-random order. RESULTS: Non-parametric analyses of variance revealed a significant group effect on the 120 ms lead interval. Retrospective analyses revealed that PPI was significantly reduced in DLB compared to healthy controls and AD. In the PDD group, the disturbance was of intermediate intensity. CONCLUSION: The present study revealed a severe disturbance of PPI in DLB patients. The DLB patients displayed a specific disruption profile in terms of magnitude as well as time course.