Functioning of the three attentional networks and vigilance in primary insomnia

Results from cognitive measures in primary insomnia (PI) patients are not consistent with the difficulties in performing daily living tasks of which these patients complain about. Lack of sensitivity of the tests and the data concerning some cognitive functions may explain this discordance. The aim of the present investigation was to better characterize cognitive deficits of PI patients in order to further understand their cognitive complaints. We looked at attentional and executive function because of their high involvement in daily living tasks.

A total of 21 PI patients and 16 good sleepers completed the Attentional Network Test (ANT). We only included untreated PI patients since sleep medication could be a confounding factor when assessing cognition.

While PI patients, compared to good sleepers, were found to have a longer overall reaction time (RT) and perform more slowly in the incongruent flanker condition (ie, conflict situation) than in the congruent condition, no group effects were observed for the variables representing the three attentional networks (ie, alerting, orienting, and executive functions).

The present study revealed a conflict resolution deficit in untreated PI patients. This impairment may be linked to the prefrontal alterations reported in neuroimaging studies in these patients. Patients had also an impaired vigilance compared to good sleepers, likely due to the high cognitive load of the ANT. These results would serve to explain the complaints of PI patients about difficulties performing daily living tasks that are demanding and of long duration.