[Essential tremor]. / Tremblement essentiel.

Essential tremor. Essential tremor is very common in the general population. It is a postural tremor occurring in adulthood, evolving progressively and whose severity can be very variable from one individual to another. A positive effect of alcohol is often reported. Its pathophysiology remains poorly understood but candidate genes have been identified in some families. From a therapeutic point of view, a first-line treatment based on propanolol or primidone may be prescribed in case of discomfort. In case of inefficiency or intolerance, second-line treatments are available but their anti-tremor effect is very variable, depending on patients. In case of pharmacoresistance, the stimulation of the VIM nucleus of the thalamus is a very effective neurosurgical option. In the case of a contraindication to stimulation, gammaknife thalamotomy (radiosurgery) may also be considered. Recently, ultrasound thalamotomy has been shown to be a promising therapy in essential tremor.

Tremblement essentiel. Le tremblement essentiel est très fréquent dans la population générale avec souvent une histoire familiale. C'est un tremblement postural familial survenant à l'âge adulte, évoluant très progressivement et dont la sévérité peut varier d'un individu à un autre. Une réponse positive du tremblement à l'alcool est classiquement rapportée. Sa physiopathologie reste mal connue mais des gènes candidats ont été identifiés dans quelques familles. D'un point de vue thérapeutique, un traitement de première ligne à base de propranolol ou de primidone peut être prescrit en cas de gêne. En cas d'inefficacité ou d'intolérance, des traitements de seconde ligne sont disponibles mais leur effet anti-trémorigène est très aléatoire au niveau interindividuel. En cas de pharmacorésistance, la stimulation du noyau ventral intermédiaire du thalamus est une option neurochirurgicale très efficace. En cas de contre-indication à la stimulation, la thalamotomie par Gamma knife (radiochirurgie) peut également être envisagée. Récemment, il a été mis en évidence que la thalamotomie par ultrasons pourrait être une thérapie prometteuse dans le tremblement essentiel.

Correction: Bee Venom for the Treatment of Parkinson Disease - A Randomized Controlled Clinical Trial.

[This corrects the article DOI: 10.1371/journal.pone.0158235.].

Bee Venom for the Treatment of Parkinson Disease - A Randomized Controlled Clinical Trial.

In the present study, we examined the potential symptomatic and/or disease-modifying effects of monthly bee venom injections compared to placebo in moderatly affected Parkinson disease patients. We conducted a prospective, randomized double-blind study in 40 Parkinson disease patients at Hoehn & Yahr stages 1.5 to 3 who were either assigned to monthly bee venom injections or equivalent volumes of saline (treatment/placebo group: n = 20/20). The primary objective of this study was to assess a potential symptomatic effect of s.c. bee venom injections (100 µg) compared to placebo 11 months after initiation of therapy on United Parkinson's Disease Rating Scale (UPDRS) III scores in the « off ¼ condition pre-and post-injection at a 60 minute interval. Secondary objectives included the evolution of UPDRS III scores over the study period and [123I]-FP-CIT scans to evaluate disease progression. Finally, safety was assessed by monitoring specific IgE against bee venom and skin tests when necessary. After an 11 month period of monthly administration, bee venom did not significantly decrease UPDRS III scores in the « off ¼ condition. Also, UPDRS III scores over the study course, and nuclear imaging, did not differ significantly between treatment groups. Four patients were excluded during the trial due to positive skin tests but no systemic allergic reaction was recorded. After an initial increase, specific IgE against bee venom decreased in all patients completing the trial. This study did not evidence any clear symptomatic or disease-modifying effects of monthly bee venom injections over an 11 month period compared to placebo using a standard bee venom allergy desensitization protocol in Parkinson disease patients. However, bee venom administration appeared safe in non-allergic subjects. Thus, we suggest that higher administration frequency and possibly higher individual doses of bee venom may reveal its potency in treating Parkinson disease. TRIAL REGISTRATION: ClinicalTrials.gov NCT01341431.

Subthalamic nucleus high-frequency stimulation restores altered electrophysiological properties of cortical neurons in parkinsonian rat.

Electrophysiological recordings performed in parkinsonian patients and animal models have confirmed the occurrence of alterations in firing rate and pattern of basal ganglia neurons, but the outcome of these changes in thalamo-cortical networks remains unclear. Using rats rendered parkinsonian, we investigated, at a cellular level in vivo, the electrophysiological changes induced in the pyramidal cells of the motor cortex by the dopaminergic transmission interruption and further characterized the impact of high-frequency electrical stimulation of the subthalamic nucleus, a procedure alleviating parkinsonian symptoms. We provided evidence that a lesion restricted to the substantia nigra pars compacta resulted in a marked increase in the mean firing rate and bursting pattern of pyramidal neurons of the motor cortex. These alterations were underlain by changes of the electrical membranes properties of pyramidal cells including depolarized resting membrane potential and increased input resistance. The modifications induced by the dopaminergic loss were more pronounced in cortico-striatal than in cortico-subthalamic neurons. Furthermore, subthalamic nucleus high-frequency stimulation applied at parameters alleviating parkinsonian signs regularized the firing pattern of pyramidal cells and restored their electrical membrane properties.