Background

Increasing age is associated with a decline in cognition and motor skills, while at the same time exacerbating one's risk of developing obstructive sleep apnea (OSA). OSA-related cognitive deficits are highly prevalent and can affect various memory systems including overnight memory consolidation on a motor sequence task. Thus, the aim of our study was to examine the effect of aging on sleep-dependent motor memory consolidation in patients with and without OSA.

Methods

We studied 44 patients (19-68 years) who had been referred by a physician for a baseline polysomnography (PSG) evaluation. Based on their PSG, patients were assigned either to the OSA group (AHI>5/h), or control (Non-OSA) group (AHI<5/h). All subjects performed the Psychomotor Vigilance Task (PVT) and the Motor Sequence Learning Task (MST) in the evening and again in the morning after their PSG.

Results

Despite similar learning in the evening, OSA subjects showed significantly less overnight improvement on the MST, both for immediate (OSA -2.7% ± 2.8% vs. controls 12.2% ± 3.5%; p = 0.002) and plateau improvement (OSA 4.9% ± 2.3% vs. controls 21.1%± 4.0%; p = 0.001). Within the OSA group, there was a significant negative correlation between overnight MST improvement and age (r(2) = 0.3; p = 0.01), an effect that was not observed in the Non-OSA group (r(2) = 0.08; p = 0.23).

Conclusions

Consistent with previous research, healthy sleepers demonstrated a higher degree of sleep-dependent overnight improvement on the MST, an effect not mitigated by increasing age. However, the presence of untreated obstructive sleep apnea is associated with an aging-related cognitive deficit, otherwise not present in individuals without OSA. As other research has linked the presence of OSA to a higher likelihood of developing dementia, future studies are necessary to examine if the inhibition of memory consolidation is tied to the onset of neurodegenerative disease.

Objective

Neurocognitive deficits are common and serious consequences of obstructive sleep apnea (OSA). Currently, the gold standard treatment is continuous positive air pressure (CPAP) therapy, although the clinical responses to this intervention can be variable. This study examined the effect of one night of CPAP therapy on sleep-dependent memory consolidation, attention, and vigilance as well as subjective experience.

Methods

Fifteen healthy controls and 29 patients with obstructive sleep apnea of whom 14 underwent a full-night CPAP titration completed the psychomotor vigilance test (PVT) and motor sequence learning task (MST) in the evening and the morning after undergoing overnight polysomnography. All participants also completed subjective evaluations of sleep quality.

Results

Participants with OSA showed significantly less overnight improvement on the MST compared to controls without OSA, independent of whether or not they had received CPAP treatment, while there was no significant difference between the untreated OSA and CPAP-treated patients. Within the OSA group, only those receiving CPAP exhibited faster reaction times on the PVT in the morning. Compared to untreated OSA patients, they also felt subjectively more rested and reported that they slept better.

Conclusion

Our results demonstrate an instant augmentation of subjective experience and, based on PVT results, attention and vigilance after one night of CPAP, but a lack of an effect on offline sleep-dependent motor memory consolidation. This dissociation may be explained by different brain structures underlying these processes, some of which might require longer continued adherence to CPAP to generate an effect.

Background

Increasing age is associated with a decline in cognition and motor skills, while at the same time exacerbating one's risk of developing obstructive sleep apnea (OSA). OSA-related cognitive deficits are highly prevalent and can affect various memory systems including overnight memory consolidation on a motor sequence task. Thus, the aim of our study was to examine the effect of aging on sleep-dependent motor memory consolidation in patients with and without OSA.

Methods

We studied 44 patients (19-68 years) who had been referred by a physician for a baseline polysomnography (PSG) evaluation. Based on their PSG, patients were assigned either to the OSA group (AHI>5/h), or control (Non-OSA) group (AHI<5/h). All subjects performed the Psychomotor Vigilance Task (PVT) and the Motor Sequence Learning Task (MST) in the evening and again in the morning after their PSG.

Results

Despite similar learning in the evening, OSA subjects showed significantly less overnight improvement on the MST, both for immediate (OSA -2.7% ± 2.8% vs. controls 12.2% ± 3.5%; p = 0.002) and plateau improvement (OSA 4.9% ± 2.3% vs. controls 21.1%± 4.0%; p = 0.001). Within the OSA group, there was a significant negative correlation between overnight MST improvement and age (r(2) = 0.3; p = 0.01), an effect that was not observed in the Non-OSA group (r(2) = 0.08; p = 0.23).

Conclusions

Consistent with previous research, healthy sleepers demonstrated a higher degree of sleep-dependent overnight improvement on the MST, an effect not mitigated by increasing age. However, the presence of untreated obstructive sleep apnea is associated with an aging-related cognitive deficit, otherwise not present in individuals without OSA. As other research has linked the presence of OSA to a higher likelihood of developing dementia, future studies are necessary to examine if the inhibition of memory consolidation is tied to the onset of neurodegenerative disease.