Veje et al.
Sleep architecture, obstructive sleep apnea and functional outcome in adults with a history of tick-borne encephalitis.
PLoS ONE. 2021; 16(2): e0246767,

Post-infectious neurological and/or neuropsychological sequelae are frequent in TBE patients. Symptoms like tiredness and fatigue, and sleep-related quality of life, have not yet been intensively investigated in individuals with a history of TBE. A study has now been presented in which the sleep architecture and obstructive sleep apnea (OSA) on polysomnography (PSG) among patients previously diagnosed with TBE compared to a control group has been analyzed.

A total of 25 TBE patients and 20 adult controls were included in a study to diagnose OSA with PSG (the gold standard). Apnea was defined as an almost complete (≥90%) cessation of airflow, and hypnea was defined as decrease in nasal pressure amplitude of ≥30% and/or thoracoabdominal movement ≥30% for >10 s if there was a significant oxyhemoglobin desaturation. OSA was defined as an apnea-hypopnea index ≥ 15 events/h of total sleep time. All patients and controls filled in a Functional Outcome of Sleep Questionnaire (FOSQ).

The total sleep time was identical in the two groups, but the proportion of sleep stages as well as OSA severity indices were significantly lower in the TBE group. Excessive Daytime Sleepiness was significantly higher among the TBE patients compared with the controls (50% vs. 20%) and the TBE patients scored statistically lower in the FOSQ scores than did the controls, and this was also the case for Intimate Relationships and Sexual Activity. TBE patients stated significantly more self-assessed daytime sleepiness/fatigue, which reflected the effect on daily life. The potential mechanisms for the origin of fatigue in TBE might be related to neurotransmitter dysfunctions. Despite the small sample size of this study, it could be shown that TBE was associated with impaired sleep-related functional outcomes independent of age, sex, total sleep time, and severity of OSA.

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