Impairment of daytime cerebrovascular reactivity in patients with obstructive sleep apnoea syndrome

Fabio Placidi, Marina Diomedi, Letizia Maria Cupini, Giorgio Bernardi, Mauro Silvestrini

Research output: Contribution to journalArticlepeer-review


Several studies have demonstrated a clear association between snoring, sleep apnoea and increased risk of stroke. However, the possible role of sleep apnoea in the pathophysiogenetic mechanisms of cerebrovascular disease is still unknown. Our aim in this study was to investigate cerebral haemodynamic changes during the waking state in eight patients with sleep apnoea syndrome (OSAS) by means of transcranial Doppler (TCD). In particular, we studied cerebral vascular reactivity (CVR) to hypercapnia calculated by means of the breath holding index (BHI). The investigation was performed in the early morning, soon after awakening, and in the late afternoon. Data were compared with those of eight healthy subjects matched for age and vascular risk factors. OSAS patients showed significantly lower BHI values with respect to controls both in the morning (0.56 vs. 1.36; P <0.0001) and in the afternoon (1.12 vs, 1.53; P <0.0001). In patients, BHI values in the afternoon were significantly higher than in the morning (P <0.0001). These data demonstrate a diminished vasodilator reserve in OSAS patients, particularly evident in the morning. This reduction of the possibility of cerebral vessels to adapt functionally in response to stimulation could be linked to hyposensitivity of cerebrovascular chemoreceptors after the continuous stress caused by nocturnal hypercapnia.

Original languageEnglish
Pages (from-to)288-292
Number of pages5
JournalJournal of Sleep Research
Issue number4
Publication statusPublished - 1998


  • Cerebrovascular reactivity
  • Sleep apnoea syndrome
  • Transcranial doppler

ASJC Scopus subject areas

  • Neuroscience(all)
  • Physiology


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