1Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru
2Department of Biostatistics, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru
3Department of Clinical Neurosciences, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru
*Correspondence Address Dr. Sanjib Sinha, MD, DM Additional Professor, Department of Neurology, NIMHANS, Hosur Road, Bengaluru-560029 E-mail: sanjib_sinha2004@yahoo.co.in
Online published on 18 April, 2014.
Background: Few studies have assessed impact of sleep related physiological events on arousals.
Methods: Overnight PSG recording of 30 healthy volunteers were analysed for occurrence of various sleep events and arousals during light sleep.
Results: 864 arousals (N1=210; N2=654) were noted during light sleep in 30 patients. Forty-three arousals were de novo (N1=18; N2=25). The mean arousal per patient was 28.8±16.3 (median: 24; range: 9–84). In N1, sleep events associated with arousals included PLM-157 (74.8%); roving eye movements-92 (43.8%); vertex transients-45 (21.4%); desaturation-5 (2.4%); snore-9 (4.3%); and apnea-3 (1.3%). In N2, sleep events associated with arousals included sleep spindle-570 (87.2%); PLM-441 (67.4%); K complex-226 (34.6%); snore-85 (13%); vertex sharp transients-57 (8.7%); desaturation-5 (0.8%); and apnea-28 (4.3%). The number of arousals in N1 and N2 that occurred de novo, and with single and multiple events were: a) N1-de novo 18 (8.6%); Single event-91 (43.3%) and multiple events-101 (48.1%); b) N2: de novo-25 (3.8%); single event-129 (19.7%) and multiple event-500 (76.5%).
Conclusions: In light sleep, 95.02% arousals were associated with physiological events viz. PLM, roving eye movements, and vertex sharp transients in N1 and sleep spindle, PLM, and K complexes in N2. Comparative studies in health and disease may enhance the understanding of arousal mechanisms.
Arousal, Polysomnography, Sleep
