RESUMEN
BACKGROUND: Transcranial direct current stimulation (tDCS) may alleviate motor symptoms in Parkinson's disease (PD). However, the neurophysiological effects of tDCS on cortical activation, synchronization, and the relation to clinical motor symptoms and motor integration need characterization. OBJECTIVE: We aimed to explore the effect of tDCS over the left sensorimotor area on clinical motor outcome, right hand fine motor performance as well as cortical activity and synchronization in the high beta range. METHODS: In this double-blind randomized sham-controlled clinico-neurophysiological study we investigated ten idiopathic PD patients and eleven matched healthy controls (HC) on two days during an isometric precision grip task and at rest before and after 'verum' and 'sham' anodal tDCS (20â¯min; 1â¯mA; anode [C3], cathode [Fp2]). We measured clinical outcome, fine motor performance, and analysed both cortical frequency domain activity and corticocortical imaginary coherence. RESULTS: tDCS improved PD motor symptoms. Neurophysiological features indicated a motor-task-specific modulation of activity and coherence from 22 to 27â¯Hz after 'verum' stimulation in PD. Activity was significantly reduced over the left sensorimotor and right frontotemporal area. Before stimulation, PD patients showed reduced coherence over the left sensorimotor area during motor task compared to HC, and this increased after 'verum' stimulation in the motor task. The activity and synchronization modulation were neither observed at rest, after sham stimulation nor in healthy controls. CONCLUSION: Verum tDCS modulated the PD cortical network specifically during fine motor integration. Cortical oscillatory features were not in general deregulated in PD, but depended on motor processing.
Asunto(s)
Corteza Cerebral/fisiopatología , Sincronización de Fase en Electroencefalografía/fisiología , Destreza Motora/fisiología , Enfermedad de Parkinson/fisiopatología , Enfermedad de Parkinson/terapia , Estimulación Transcraneal de Corriente Directa , Adulto , Anciano , Método Doble Ciego , Femenino , Humanos , Masculino , Persona de Mediana Edad , Placebos , Procesamiento de Señales Asistido por Computador , Resultado del TratamientoRESUMEN
BACKGROUND: Current efforts to improve clinical effectiveness and utility of repetitive transcranial magnetic stimulation (rTMS) in the treatment of major depression (MD) include theta burst stimulation (TBS), a patterned form of rTMS. Here, we investigated the efficacy of bilateral TBS to the dorsolateral prefrontal cortex (dlPFC) in patients with MD in additon to ongoing medication and psychotherapy. METHODS: In this randomized-controlled trial, thirty-two patients with MD were treated for six weeks (thirty sessions) with either successively intermittent, activity enhancing TBS (iTBS) to the left and continuous, inhibiting TBS (cTBS) to the right dlPFC or with bilateral sham stimulation. Primary outcome measure was the proportion of treatment response defined as a Montgomery-Åsberg Depression Rating Scale (MADRS)≤50% compared to baseline. Secondary outcomes comprised response and remission rates of the Hamilton Depression Rating Scale (HAMD) and the Beck Depression Inventory (BDI). RESULTS: A larger number of responders were found in the cTBS (n=9) compared to the sham-stimulation (n=4) group (odds ratio: 3.86; Wald χ(2)=3.9, p=0.048). On secondary endpoint analysis, patient-reported outcome as assessed by the BDI, pointed towards a higher rate of remitters in the cTBS (n=6) than in the sham (n=1) group (odds ratio: 9; Wald χ(2)=3.5, p=0.061). LIMITATIONS: With regard to the pilot character of the study and the small sample size, the results have to be considered as preliminary. CONCLUSIONS: These findings provide first evidence that six weeks treatment of MDD with iTBS to the left and cTBS to the right dlPFC for six weeks is safe, feasible and superior to sham stimulation applied add-on to pharmacological and psychotherapeutic treatment.
Asunto(s)
Trastorno Depresivo Mayor/terapia , Estimulación Magnética Transcraneal/métodos , Adulto , Anciano , Antidepresivos/uso terapéutico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Proyectos Piloto , Corteza Prefrontal , PsicoterapiaRESUMEN
BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) for the experimental treatment of tinnitus or auditory hallucinations aims at a modulation of cortical activity in areas of auditory perception and processing. Continuous theta burst stimulation (cTBS) is a patterned rTMS paradigm with lower stimulation intensity and shorter stimulus duration that is increasingly used for the optimization of rTMS-treatment paradigms. Possible interference with physiological brain function and the noise emitted by the rTMS device might induce relevant unwanted impairment of hearing and speech perception. OBJECTIVE/HYPOTHESIS: Here, we investigate the audiological safety of long-term, bilateral cTBS for the treatment of auditory phantom perception. METHODS: Forty-eight patients with chronic tinnitus were treated for four weeks with bilateral continuous theta burst stimulation to the temporal (n = 16), temporoparietal (n = 16) or a non-cortical control (n = 16) site. Measurements in these patients were obtained before and four weeks after treatment. The rTMS-induced noise was measured at various frequency levels. RESULTS: No evidence was found for auditory threshold shifts or alterations in the perception of speech in quiet or in background noise by bilateral, long-term theta burst stimulation to the temporal or temporoparietal cortex with a loudness of up to 84 dB SPL (A). CONCLUSIONS: Theta burst stimulation of the temporal and temporoparietal cortex appears to be safe with respect to hearing and speech perception. These data provide evidence for the audiological safety of rTMS in the experimental treatment of auditory phantom perception.