Showing papers by "Marie Vidailhet published in 2006"

Psychogenic parkinsonism: A combination of clinical, electrophysiological, and [123I]‐FP‐CIT SPECT scan explorations improves diagnostic accuracy

Abstract: We evaluated the concordance between independent clinical, electrophysiological, and [123I]-FP-CIT SPECT scan explorations as a staged procedure for an accurate diagnosis in 9 patients referred with a diagnosis of suspected psychogenic parkinsonism. Three patients were reclassified as pure psychogenic parkinsonism (PP), 6 with a form of combined psychogenic parkinsonism and Parkinson's disease (PP + PD), and none with pure Parkinson's disease (PD). Electrophysiological recordings showed the characteristics of psychogenic tremor in 5 of 7 patients with tremor. In two of these 5, PD tremor was also recorded. SPECT scan results were abnormal in five of 9 patients. In one case of clinically suspected PP + PD, SPECT scan results were normal. Long-term follow-up supported the final diagnosis of PP (initial clinical misdiagnosis). Electrophysiology contributes to the clinical diagnosis of psychogenic tremor and may help confirm associated organic PD tremor. [123I]-FP-CIT SPECT is a robust test to ascertain dopaminergic denervation and increase the confidence of the clinical and electrophysiological diagnosis of associated PD. A combination of clinical, electrophysiological, and [123I]-FP-CIT SPECT scan explorations improves diagnostic accuracy in order to distinguish PP from PP + PD. © 2005 Movement Disorder Society

Mixing pro- and antisaccades in patients with parkinsonian syndromes.

Abstract: Prosaccades and antisaccades were investigated in three groups of patients with parkinsonian syndromes, Parkinson's disease, corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP), and in a control group. Saccade tasks were performed in single-task blocks (i.e. either blocks of prosaccades or blocks of antisaccades) and in mixed-task blocks (i.e. in blocks of randomly interleaved pro- and antisaccades). Saccade latencies and directional errors (misdirected saccades) were analysed in each subject, and we concentrated more specifically on the comparison of error rates in single tasks and in repeated trials of mixed tasks (i.e. mixing costs). The performance of each group in single tasks was largely consistent with previous studies, with normal antisaccade error rates in Parkinson's disease and CBD patients and increased antisaccade error rates in PSP patients. In contrast, a double dissociation was observed in mixed tasks. Parkinson's disease and CBD patients showed a marked increase in prosaccade and antisaccade error rates in repeated trials of mixed tasks, illustrated by increased mixing costs, whereas PSP patients showed similar error rates in single and repeated trials of mixed tasks, i.e. normal mixing costs. These results demonstrate that: (i) antisaccade performances may be differentially affected in mixed tasks and single tasks; (ii) the region of the dorsolateral prefrontal cortex which is crucial for reflexive saccade inhibition does not seem to be involved in the additional processes required in mixed-task conditions; (iii) the study of interleaved pro- and antisaccades may increase the accuracy of the differential diagnosis between these parkinsonian syndromes.

Head tremor in Parkinson's disease.

Abstract: Head tremor is a typical feature of essential tremor. Patients with sporadic Parkinson's disease can have tremor of the tongue, lip, or chin, but classically do not have head tremor. We describe five patients with Parkinson's disease and head tremor in whom clinical and neurophysiological findings suggested that head tremor was a manifestation of Parkinson's disease.

Time–frequency analysis reveals decreased high-frequency oscillations in writer's cramp

Abstract: High-frequency oscillations (HFO) have been suggested to reflect the activity of thalamocortical and/or intracortical neurons bursting at high frequencies. These circuits seem to be involved in pathophysiological mechanisms of focal dystonia. In healthy subjects, we characterized the spectrotemporal properties of HFO patterns evoked by dominant-hand median-nerve stimulation, using magnetoencephalography coupled with time-frequency analysis. Then, we investigated HFO in patients with writer's cramp and found that HFO patterns are strongly decreased in power and disorganized in time. This supports the assumption that abnormal HFOs reflect pathophysiological mechanisms occurring in focal dystonia, possibly resulting from a dysfunction of somatosensory processing.

Deep brain stimulation of the globus pallidus for generalized dystonia in GM1 Type 3 gangliosidosis: technical case report.

Abstract: Objective GM1 Type 3 gangliosidosis is a lysosomal storage disorder for which no specific treatment is available. It is characterized by progressive generalized dystonia, which is refractory to pharmacological treatment and results in severe disability and life-threatening complications. We performed bilateral pallidal stimulation in a patient with GM1 gangliosidosis and report the 12-month postoperative course. Clinical presentation A 24-year old woman presented with genetically confirmed GM1 gangliosidosis, resulting in severe progressive generalized dystonia. Intervention Leads were implanted bilaterally into the internal part of the globus pallidus under stereotactic guidance. At follow-up visits, both the patient and the neurologists who performed the assessment were unaware of whether the neurostimulator was on or off. The patient was videotaped with a standardized protocol and scored by an independent expert. Conclusion After 1 year of follow-up, double-blind comparison of the patient's status with and without neurostimulation showed a 20% improvement, with a significant functional benefit, but no change in disease progression. Although further studies are needed to evaluate this therapeutic approach, this report suggests that pallidal stimulation might be a promising treatment for dystonia caused by GM1 Type 3 gangliosidosis.

Clinical analysis in familial cortical myoclonic tremor allows differential diagnosis with essential tremor.

Abstract: Familial cortical myoclonic tremor (FCMT) is a rare disorder often leading to a wrong clinical diagnosis of essential tremor. Electrophysiological data are usually considered to allow a correct diagnosis. We describe a FCMT French family with previously unreported clinical features such as sensitivity to glucose deprivation, vibration, repetitive visual patterns, and intense visual or auditory stimulation and contrasts. Electrophysiological studies of the propositus confirm the cortical reflex myoclonus elicited by photic stimulation and the absence of epileptic electroencephalographic discharges. We emphasize that a precise clinical analysis can lead to a correct diagnosis before electrophysiological confirmation. This is also the first-ever report of efficacy of levetiracetam in FCMT.

Lack of inhibitory interaction between somatosensory afferent inputs and intracortical inhibitory interneurons in focal hand dystonia.

Abstract: We looked for an impaired interaction in the primary motor cortex between intracortical inhibitory circuits and circuits fed by somatosensory inputs in patients with writer's cramp. Short-interval intracortical inhibition (sICI) to wrist extensor carpi radialis muscle (ECR) was conditioned by stimulation of antagonist muscle afferents and sICI to first dorsal interosseus (FDI) muscle by homotopic cutaneous afferents stimulation. sICI was assessed at rest and during a tonic contraction of the target muscle. Eighteen patients with writer's cramp (10 having a wrist dystonic posture in flexion during writing and 8 in extension) were compared to 14 control subjects. Peripheral inputs decreased sICI in control subjects. This decrease was lost in patients in both FDI and ECR, regardless of the wrist dystonic posture. By contrast, contraction-induced depression of sICI appeared dependant on the dystonic status of the muscle: depression of sICI to ECR was abolished in patients with wrist dystonic posture in flexion, but not in patients with dystonic posture in extension, sICI even giving way to motor-evoked potential facilitation. Loss of interaction between interneurons mediating sICI and peripheral inputs probably belongs to the initial abnormalities underlying dystonia. Lack of peripherally induced sICI modulation may oppose wrist and/or hand muscles synergies.

Long-term follow-up and adult outcome of 6-pyruvoyl-tetrahydropterin synthase deficiency

Abstract: Little information is available on the long-term course and adult outcome of patients with 6-pyruvoyl-tetrahydropterin synthase (PTPS) deficiency. We describe the course of a 32-year-old woman with hypotonia, dystonia, choreoathetosis, mental retardation, behavioral disturbances, and incomplete puberty due to PTPS deficiency. From the age of 6 months she developed progressive hypotonia and choreoathtetoid movements despite good control of hyperphenylalaninemia. Tetrahydrobiopterin deficiency was diagnosed at age 3 years. She had a dramatic response to L-dopa, which persisted at a stable dose for 29 years. Reducing the L-dopa dose led to severe axial hypotonia and limb dystonia, and increasing it led to florid abnormal movements and behavioral disorders. This report illustrates the role of dopamine modulation in motor, psychiatric, and endocrine functions.

Interictal myoclonus with paroxysmal kinesigenic dyskinesia

Abstract: We report a new association between interictal myoclonus and paroxysmal kinesigenic dyskinesia (PKD) in 2 patients. By definition, PKD is transient, but the overexcitability of the neuronal system that induces these attacks may be permanent. Interictal myoclonus could be a manifestation of permanent overexcitability.