RESUMEN
Orthostatic tremor (OT) is a disabling movement disorder associated with postural and gait impairment in the elderly. Medical therapy often yields insufficient benefit. We report the clinical and electrophysiological data on two patients with medication-refractory OT treated with deep brain stimulation of the ventral intermediate thalamic nucleus (Vim DBS). Patient 1 underwent bilateral deep brain stimulation (DBS) and Patient 2 unilateral Vim DBS following 28 and 30 years of disease duration, respectively. Both patients showed increased latency to symptom onset after rising from a seated position, improved tolerance for prolonged standing, and slower crescendo of tremor severity when remaining upright. Postoperative evaluation demonstrated decreased amplitude of electromyographic activity with persistence of well-defined oscillatory behavior showing strong coherence at 15 Hz between all muscles tested in the upper and lower limbs. Postural sway was unchanged. Clinical benefits have been sustained for over 18 months in Patient 1, and receded after 3 months in Patient 2. These findings support the consideration of bilateral Vim DBS implantation as a therapeutic option in patients with medically refractory OT. Further efficacy studies on chronic stimulation to disrupt the abnormal oscillatory activity in this disorder are warranted.
Asunto(s)
Estimulación Encefálica Profunda/métodos , Tálamo/fisiología , Temblor/terapia , Anciano , Electromiografía/métodos , Femenino , Humanos , Pruebas Neuropsicológicas , Tálamo/cirugía , Temblor/fisiopatologíaRESUMEN
Empleando un modelo de doble alternativa de elección: droga VS. alimento en perros sometidos a un cocainismo experimental, se encuentra que los animales tienden a elegir la droga a pesar de la administración de bromocriptina. Los resultados obtenidos viabilizan la propuesta de una prevalencia del condicionamiento clásico de señales en la instauración de la adicción cocaínica, al cual estaría asociado un condicionamiento operante de señales para el mantenimiento del comportamiento adictivo