Actigraphic assessment of sleep-wake rhythm during the first 6 months of life.

Objectives: To examine the validity of the "Gaehwiler" actigraph (Gaehwiler Electronics, model Z80-32k V(1)) for the assessment of sleep-wake (S/W) rhythm and sleep structure in infants during the first 6 months of life using an algorithm developed in our laboratory to differentiate sleep and wake states.

Methods: A continuous 72 h actigraphic recording was performed in 10 healthy infants at 1, 3 and 6 months of age. The actigraphic data were matched to direct observation of the infants' behavioural states.

Long sensory tracts (cuneate fascicle) in cervical somatosensory evoked potential after median nerve stimulation.

Low amplitude high frequency waves (LHW) were investigated in normal and patient cervical somatosensory evoked potentials after median nerve stimulation (CSEP) in parallel to normal and patient conducted somatosensory evoked potentials (SEP) after tibial nerve stimulation. Normal recordings were obtained in five subjects undergoing dorsal root entry zone (DREZ) coagulation for pain relief. Patient recordings were obtained in 11 subjects suffering from either syringomyelia, spinal cord tumour, or both.