Memory monitoring and memory control in patients suffering from obstructive sleep apnoea syndrome

Patients with obstructive sleep apnoea syndrome exhibit memory deficit. The present study looked at whether this deficit is related to impaired memory monitoring and/or memory control. Here 25 patients and 26 healthy controls performed a paired-associate learning task. After participants had made a judgement of learning for each pair and performed an initial recall test they were free to restudy any items they wished, for as long or little as they wished, within a 5-minute period. They then performed a second recall test. Monitoring and control processes were assessed on the basis of judgements of learning, item selection, and study-time allocation. In spite of their memory impairment, patients accurately predicted their recall. For the restudy phase patients preferentially selected the judged-easy items, while controls selected the judged-difficult items. However, all the participants allocated more restudy time to the judged-difficult items than to the judged-easy ones. There were no significant correlations between memory performance, metamemory processes, and clinical measures (i.e., subjective sleepiness, subjective sleep quality, anxiety, and depression scores). Results suggested that both memory monitoring and memory control were preserved in our sample of patients with obstructive sleep apnoea.