High Sleep Spindle Density With Insomnia

Document Type

Conference Proceeding

Publication Date

10-2024

Publication Title

Chest

Abstract

INTRODUCTION: A sleep spindle (polysomnographic) is a 11-15 Hz frequency train of EEG waves with a duration of 0.5 to 2 seconds, seen in NREM sleep and are characteristic of N2 stage. Sleep spindles may have a role in memory consolidation and sleep protection from arousing stimuli. We present a case with high sleep spindle density in the setting of chronic insomnia. CASE PRESENTATION: A 35-year-old male with no significant past medical history presented with chronic insomnia. Polysomnography (PSG) performed at outside center showed apnea hypopnea index (AHI) of 5.5/hour. He didn't follow up after that PSG and came to our clinic. Started on AutoCPAP but despite of that he continues to have insomnia and daytime sleepiness. PAP titration study was ordered given good compliance with CPAP and ongoing symptoms. Titration PSG was notable for a high spindle density of 16-18/min. The patient was not on any narcotics, neuropsychiatric medications, benzodiazepines, antidepressants, melatonin, or medications known to affect sleep spindle density. His body mass index was 21. Laboratory testing and chest imaging was unremarkable. DISCUSSION: Sleep spindle density is defined as number of spindles per minute. The thalamus is crucial in spindle production and plays a role in wakefulness and NREM sleep. Studies show an increased resilience to external disturbances with higher sleep spindle densities. A longer duration of sleep time spent in N2 stage correlates with higher number of sleep spindles and periodic limb movements. Sleep spindle density typically peaks in adolescence and increased after learning period. Reported density in literature per our review was 6-10/minute. It may be associated with increased N2 and decreased N3 sleep duration. Our patient had 77.1% N2 sleep (Normal ~50%) and 5.1% N3 sleep (Normal ~20%). One study noted increased spindle density in idiopathic hypersomnia and narcolepsy, but our patient has insomnia as well. Studies have reported lower spindle activity predicting increased insomnia paradoxical to our case with insomnia and high number of sleep spindles. Benzodiazepines have a strong association with increased spindle density. Sleep spindle density correlates with markers of intelligence, but also with several disorders leading to cognitive deficits and dementia. CONCLUSIONS: Spindles play a role in sleep regulation and cognitive function. A higher spindle density is associated with a longer duration of N2 sleep and shorter duration of N3 sleep with a possible association with sleep instability. A better understanding of their spatiotemporal distribution and density could become useful for diagnostic purposes.

Volume

166

Issue

4 Suppl

First Page

A6176

Last Page

A6177

Comments

Chest 2024 Annual Meeting, October 6-9, 2024, Boston, MA

DOI

10.1016/j.chest.2024.06.3657

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