Visual Dysfunction and Computational Sleep Depth Changes in Obstructive Sleep Apnea Syndrome

Abstract

The aims of this study are to clarify whether patients with obstructive sleep apnea syndrome (OSAS) have a decline in verbally or visually-based cognitive abilities and whether the possible decline is related to particular sleep depth changes. In addition, the effect of continuous positive airway pressure (CPAP) on the possible changes is investigated. Fifteen OSAS patients and 15 healthy controls joined two full-night polysomnographies, including a computational measure of deep sleep percentage (DS%) bilaterally from the frontal, central and occipital channels, and a neuropsychological assessment. After a 6-month CPAP the patients underwent one more full-night polysomnography with computational DS% analysis and a neuropsychological assessment. At the baseline, the OSAS patients had poorer performance in the Picture Completion, in the Digit Symbol and in copying the Rey-Osterrieth Complex Figure Test (ROCFT) compared to the controls. The patients also showed reduced DS% in all 6 electrographic (EEG) channels compared to controls. The patients had an inter-hemispheric difference showing less deep sleep in the right hemisphere than in the left hemisphere both frontopolarly and centrally, while the controls showed this inter-hemispheric difference only frontopolarly. After CPAP the patients still had poorer performance in the Picture Completion and in the ROCFT. The patients continued to show reduced DS% in all 3 channels of the right hemisphere and occipitally in the left hemisphere, also the inter-hemispheric difference frontopolarly and centrally remained. OSAS patients have mild visually based cognitive dysfunction and reduced amount of deep sleep in the right hemisphere even after CPAP.

Role of Oxidative Stress in the Neurocognitive Dysfunction of Obstructive Sleep Apnea Syndrome

“…The research by Twigg et al [ 62 ] has shown that verbal but not visual memory was impaired in OSA patients. Yet, it was found that OSA patients have mild visual cognitive dysfunction [ 63 ]. And a recent meta-analysis which included 42 researches revealed that verbal episodic memory and visuospatial episodic memory mainly representing the domain of immediate and delayed recall were disturbed in OSA in comparison to healthy group [ 64 ].…”

Difference in spectral power density of sleep EEG between patients with simple snoring and those with obstructive sleep apnoea

“…daytime sleepiness and attention or vigilance dysfunction [25][26][27][28][29][30][31] . Studies using sleep EEG derived from PSG have documented significant differences in spectral power or sleep spindles during non-rapid eye movement (NREM) sleep between patients with OSA and controls [32][33][34][35] . Although previous spectral analysis studies have investigated EEG and oximetric spectral features to improve OSA detection 21 , little is known about differences in sleep qEEG between patients with SS and those with OSA.…”

Prolonged partial obstruction during sleep is a NREM phenomenon

“…They also have deeper sleep than OSA patients in all EEG derivations. Moreover, they present with lighter sleep than healthy controls in the same EEG derivations that show a reduced amount of slow EEG frequencies in OSA patients with six months of CPAP treatment (Saunamaki et al, 2009). Poor quality sleep might explain some of the subjective symptoms of PPO patients.…”