Sleep is a physiological state necessary for memory processing, learning and brain plasticity. Patients with disorders of consciousness (DOC) show none or minimal sign of awareness of themselves or their environment but appear to have sleep-wake cycles. The aim of our study was to assess baseline circadian rhythms and sleep in patients with DOC; to optimize circadian rhythm using an intervention combining blue light, melatonin and caffeine, and to identify the impact of this intervention on brain function using event related potentials.
View Article and Find Full Text PDFPurpose: To detect any improvement of awareness in prolonged disorders of consciousness in the long term.
Methods: A total of 34 patients with prolonged disorders of consciousness (27 vegetative state and seven minimally conscious state; 16 males; aged 21-73) were included in the study. All patients were initially diagnosed with vegetative/minimally conscious state on admission to our specialist neurological rehabilitation unit.
Objective: Long-range temporal correlations (LRTC) of EEG amplitude fluctuations in adults reveal power-law statistics and have been interpreted within the framework of self-organized criticality (SOC). In physical systems states of self-organized criticality showing power-law statistics take time to develop. In this paper we have sought evidence for the idea that brain development tends towards SOC through examining the hypothesis that during normal human development a power law behaviour of EEG oscillations is approached with increasing chronological age.
View Article and Find Full Text PDFChanges in coherence and cumulant calculated between electroencephalograph (EEG) recorded from the scalp over primary motor cortex and rectified surface electromyograph (EMG) recorded from the contralateral wrist extensor muscles have been studied during development in humans (48 subjects, age 0-59 years). Using the techniques of EEG-EMG coherence and cumulant analysis and pooled coherence and cumulant analysis we demonstrate that between childhood, adolescence and adulthood there are increases in the prevalence and magnitude of coherence at frequencies between 15 and 35 Hz with corresponding development of a tri-phasic feature in the EEG-EMG cumulant. The results show for the first time that changes in the cortical approximately 20 Hz oscillatory drive to human motoneurone pools take place during motor development.
View Article and Find Full Text PDFIn adults, motoneurone pools of synergistic muscles that act around a common joint share a common presynaptic drive. Common drive can be revealed by both time domain and frequency domain analysis of EMG signals. Analysis in the frequency domain reveals significant coherence in the range 1-45 Hz, with maximal coherence in low (1-12 Hz) and high (16-32 Hz) ranges.
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