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The effect of sleep on intracranial hemodynamics: a transcranial Doppler study
A Q Fischer1, M A Taormina, B Akhtar
1Department of Neurology, Sleep Disorder Center, Medical College of Georgia, Augusta 30912.
Insights
Sleep significantly reduces intracranial blood flow velocities in both children and adults. These findings are crucial for interpreting transcranial Doppler (TCD) measurements during sleep.
Area of Science:
- Neurology
- Sleep Medicine
- Vascular Physiology
Background:
- Intracranial blood flow velocities are clinically assessed during sleep and wakefulness.
- The impact of sleep on these velocities remains largely unreported in both pediatric and adult populations.
Purpose of the Study:
- To investigate the effect of sleep on intracranial blood flow velocities.
- To compare these effects in healthy children and adults.
Main Methods:
- Utilized polysomnography and transcranial Doppler sonography (TCD) in 11 healthy individuals (5 children, 6 adults).
- Measured systolic, end-diastolic, and mean flow velocities in middle cerebral arteries before, during, and after sleep.
- Monitored pulse oximetry and end-tidal carbon dioxide throughout 8-hour polysomnograms.
Main Results:
- A significant decrease in blood flow velocities was observed during sleep compared to pre-sleep values in both children (P < .05) and adults (P < .01).
- Blood flow velocities remained decreased after sleep compared to before-sleep measurements.
Conclusions:
- Normal sleep demonstrably reduces intracranial blood flow velocities in both pediatric and adult subjects.
- Clinicians should consider sleep-related reductions when interpreting TCD findings in patients.
Abstract:
The effect of sleep on intracranial blood flow velocities has not been reported in children or adults, even though blood flow velocities are evaluated for clinical purposes during both sleep and wakefulness. We report the effect of sleep on intracranial blood flow velocities of 11 healthy individuals (five children and six adults) who were monitored by polysomnography and transcranial Doppler sonography (TCD). Thirty-three TCDs were obtained on middle cerebral arteries. Before sleep, during non-rapid-eye-movement sleep, and after sleep, measurements of systolic, end diastolic, and mean flow velocities were obtained by TCD. Pulse oximetry and end tidal carbon dioxide were monitored during each 8-hour polysomnogram. The before-sleep blood flow velocity values were compared to sleep and after-sleep values in children and adults separately using ANOVA. A significant decrease in the blood flow velocities was noted during sleep compared to before-sleep values in both children (P less than .05) and adults (P less than .01). The blood flow velocities after sleep were also decreased compared to before-sleep values. This study shows that sleep reduces blood flow velocities in both children and adults. A decrease in blood flow velocities during normal sleep should be taken into account when interpreting TCDs in patients.