Parkinson’s disease

Problems with sleep and daytime vigilance are usually both present in the top three of complaints most affecting the quality of life in Parkinson’s disease. The monitoring of sleep-wake rhythms in field studies cannot validly be done using the regular actigraph, because high levels of activity can both mean unconstrained physical activity as well as debilitating tremor. We therefore developed and validated a dedicated actigraph that allows for unrestricted long-term simultaneous monitoring of both tremor and normal physical activity (Van Someren et al., 2006). Using this system, we demonstrated that the application of by repetitive transcranial magnetic stimulation (rTMS) over the parietal, but not over the motor cortex improved sleep considerably (Van Dijk et al., in revision). The finding supports the recent idea that local differences in cortical sleep pressure can be induced with local differences in neuronal activation during prior wakefulness. They also extend previous findings suggesting that higher order cortical areas have a leading role in the expression of sleep-related cortical activity – in contrast to the predominant primary to higher-order cortical area information stream typical of wakefulness.