The impact of obstructive sleep apnea on motor skill acquisition and consolidation

Abstract

Study objective: Recent investigations suggest that motor skill learning is impaired in patients with obstructive sleep apnea (OSA) syndrome; however, it is not fully understood at what stages of learning this impairment occurs. The current study aimed to compare motor learning and memory across both daytime acquisition and overnight consolidation.

Methods: Twelve OSA patients and twelve control participants, matched for age and education, were recruited and completed the Karolinska Sleepiness Scale and the sequential finger-tapping task (SFTT), a motor skill learning task, both before and after polysomnographic recorded sleep.

Results: During the evening acquisition phase both groups showed significant and equitable improvement in the number of correctly typed sequences across trials. On retesting the following morning, the control patients showed significantly greater improvement overnight (15.35%) compared to OSA patients (1.78%). The post sleep improvement in controls, but lacking in OSA patients, was typical of a sleep dependent enhancement effect. The magnitude of improvement overnight for either group was not significantly correlated with any of the recorded sleep variables.

Conclusions: These results suggest daytime/practice related acquisition of motor skill is largely intact in OSA patients; however, marked impairment in the consolidation phase is evident following a sleep period. This particular pattern of dysfunction may remain unnoticed following single-day learning/memory assessments.

Keywords: OSA; learning; memory; motor skills; obstructive sleep apnea; sleep-dependent consolidation.

Figure 1. Mean number of correctly typed sequences for each pre-sleep practice trial (E1-12) and post-sleep testing trial (M1-12) for both OSA patients (n = 12, triangles) and control participants (n = 12, squares).

The separating gray bar donates the recorded sleep period. Lined bars represent the overnight consolidation related improvement which was greater for control participants (2.97 ± 0.73 sequences, 15.35%) than OSA patients (0.27 ± 0.45 sequences, 1.78%). Dotted lines represent, for each group, the mean values for the last 3 pre-sleep practice trials (E10-E12) and the first 3 post-sleep testing trials (M1-M3).