CHRONIC HICCUPS AND SLEEP

To explore the effect of sleep on hiccups, we studied eight patients a ged 20-81 years, all males with chronic hiccups lasting 7 days to 7 ye ars, by means of overnight polysomnography. The incidence of new bouts of hiccups and the likelihood of hiccups being present were both high est in wakefulness and became progressively lower through stages I-IV of slow wave sleep (SWS) to rapid eye movement sleep (REMS). There was a significant tendancy for hiccups to disappear at sleep onset and RE MS onset. Of all 21 bouts of hiccups that were observed to stop, 10/21 did so during an apnea or hypopnea. Frequency of hiccups within a bou t slowed progressively from wakefulness through the stages of SWS to R EMS. For the whole group, mean frequency decreased significantly from wakefulness [(25.6 +/- 12.1), (mean +/- SD)] to sleep onset or stage I (22.3 +/- 12.2). Sleep latency was increased from 8 +/- 16.3 minutes when hiccups were absent to 16.35 +/- 19.9 minutes when it was present . Sleep efficiency was poor because of long waking periods, and there were defiencies of both SWS and REMS. Hiccups themselves were not resp onsible for any arousals or awakenings. We conclude that neural mechan isms responsible for hiccups are strongly influenced by sleep state an d that hiccups disrupt sleep onset but not established sleep.