Specific EEG sleep pattern in the prefrontal cortex in primary insomnia.

OBJECTIVE: To assess the specific prefrontal activity in comparison to those in the other main cortical areas in primary insomnia patients and in good sleepers. METHODS: Fourteen primary insomnia patients and 11 good sleepers were included in the analysis. Participants completed one night of polysomnography in the sleep lab. Power spectra were calculated during the NREM (Non-rapid eyes movements) and the REM (Rapid eyes movements) sleep periods at prefrontal, occipital, temporal and central electrode positions. RESULTS: During the NREM sleep, the power spectra did not differ between groups in the prefrontal cortex; while primary insomnia patients exhibited a higher beta power spectrum and a lower delta power spectrum compared to good sleepers in other areas. During the REM sleep, the beta1 power spectrum was lower in the prefrontal cortex in primary insomnia patients compared to good sleepers; while no significant difference between groups was obtained for the other areas. CONCLUSIONS: The present study shows a specific prefrontal sleep pattern during the whole sleep period. In addition, we suggest that primary insomnia patients displayed a dysfunction in the reactivation of the limbic system during the REM sleep and we give additional arguments in favor of a sleep-protection mechanism displayed by primary insomnia patients.

Impaired driving performance associated with effect of time duration in patients with primary insomnia.

STUDY OBJECTIVES: To evaluate driving performance and psychomotor vigilance in patients with primary insomnia. DESIGN: After 1 night of polysomnography, participants performed a 1-h simulated monotonous driving task and a psychomotor vigilance task (PVT). Self-ratings of sleepiness, mood, and driving performance were completed. SETTING: This study was conducted at the CHU of Caen Sleep Unit and the University of Caen. PARTICIPANTS: Twenty-one primary insomnia patients and 16 good sleepers. INTERVENTIONS: Not applicable. MEASUREMENTS AND RESULTS: Results revealed a larger standard deviation of lateral position (P = 0.023) and more lane crossings (P = 0.03) in insomnia patients than in good sleepers. Analyses of effect of time on task performance showed that the impairment in patients occurred after 20 min of driving, which was not the case for good sleepers. No difference between groups was found for the PVT, neither for the mean reaction time (RT) (P = 0.43) nor the number of lapses (P = 0.21) and the mean slowest 10% 1/RT (P = 0.81). Patients rated their sleepiness level higher (P = 0.06) and their alertness level lower (P = 0.007) than did good sleepers (P = 0.007). The self-evaluation of the driving performance was not different between groups (P = 0.15). CONCLUSIONS: These findings revealed that primary insomnia is associated with a performance decrement during a simulated monotonous driving task. We also showed that patients are able to drive safely only for a short time. It appears advisable for clinicians to warn patients about their impaired driving performance that could lead to an increased risk of driving accidents.

Zolpidem and zopiclone impair similarly monotonous driving performance after a single nighttime intake in aged subjects.

RATIONALE: Although hypnotics are primarily used by older people, the residual effects the morning after a single nighttime intake of the two most commonly prescribed hypnotics, zolpidem (Zp) and zopiclone (Zc), on older middle-aged drivers have not been evaluated and compared. METHODS: Sixteen healthy subjects, 55 to 65 years of age, participated in this double-blind, balanced, cross-over study. Zc (7.5 mg), Zp (10 mg) and flunitrazepam (Fln) (1 mg) or a placebo was administered at each subject's home at 11.00 pm. The next morning, at 9.00 am, the subjects had to drive in a simulated monotonous driving environment for 1 h. During each morning session, two blood samples were collected, and subjective feelings of alertness were completed three times. RESULTS: In comparison to placebo, Zp and Zc equivalently and significantly impaired the standard deviation of lateral position, the standard deviation of speed and the number of road exits. Detectable blood concentrations were found with Zp in 11 subjects at 8.30 am and at 1.30 pm. The subjective alertness factor was significantly impaired with Zp. CONCLUSIONS: This is the first study revealing residual effects of Zp on driving performance in ageing drivers which are similar to that of Zc. Studying the effects of medication in different age ranges appears useful to complete the studies on behavioural-pharmacological effects of medication. To reduce the incidence of driving accidents due to prescription drugs, patients should be warned at the time of treatment initiation that they should avoid driving.