Annie Mathieu

Slow-wave sleep and delta power in rapid eye movement sleep behavior disorder

Rapid eye movement (REM) sleep behavior disorder (RBD) is characterized by the loss of normal muscle atonia during REM sleep, leading to an increase of phasic muscle activity and complex motor behaviors during the night. There is some evidence that RBD patients have more of slow‐wave sleep (SWS) than healthy elderly subjects. No study has looked at quantitative electroencephalogram analysis during non‐REM sleep in either primary or secondary RBD. The aim of this study was to assess the increase of SWS and to analyze different electroencephalographic frequency ranges during non‐REM sleep in 28 idiopathic RBD patients compared with 28 age‐ and sex‐matched healthy volunteers. Idiopathic RBD patients spent more time in SWS (men: 1.4%; women: 5.9%) than control subjects (men: 0.4%; women: 0.6%; p = 0.004). Spectral analyses demonstrated that idiopathic RBD patients had increased all‐night δ power in comparison with control subjects (p = 002). This study shows an increase of SWS and power in the δ band during non‐REM sleep in idiopathic RBD patients compared with control subjects. Results are discussed about the possible nigrostriatal dopaminergic impairment in RBD patients and the association between RBD and neurodegenerative disorders. Ann Neurol 2005;57:277–282

Attentional deficits in patients with obstructive sleep apnea syndrome: An event-related potential study

OBJECTIVE Patients with obstructive sleep apnea syndrome (OSAS) show cognitive deficits, vigilance alteration and attentional decline. The aim of this study was to use event-related potentials (ERP) to further document the attentional impairments in these patients. METHODS Twelve OSAS patients and 12 age-matched controls underwent the ERP task which consisted in the presentation of short (50ms, 50%) and long tones (400ms, 50%). For these two categories, 90% were standard (1000Hz) and 10% were deviant tones (750 or 1250Hz). Subjects had to discriminate short and long tones by a motor response. RESULTS OSAS patients had a sustained and delayed P300 in comparison with control subjects following standard tones (p<0.05). A reduction in amplitude was found in OSAS patients for the P3a obtained by the subtraction of standard from deviant tones (p<0.05). No group difference was observed for N1, mismatch negativity and reorienting negativity components. CONCLUSIONS Apneas and hypopneas produce deficits related to involuntary attentional switch and stimulus classification processing. SIGNIFICANCE The changes observed in P3a and P300 components further support the hypothesis that attentional deficits play a pivotal role in cognitive deficits noted in OSAS.

Deficits in involuntary attention switching in obstructive sleep apnea syndrome

Cognitive functions are altered in patients with obstructive sleep apnea syndrome (OSAS) and it has been proposed that vigilance and attentional deficits play a pivotal role in all aspects of these deficits. One way to assess attentional system integrity is the study of event-related-potentials (ERP), but only a few ERP studies have been conducted in patients with OSAS. The aim of the study was to use ERP to further assess attentional impairments in these patients. Thirteen OSAS patients and 13 age-matched controls underwent a night of polysomnographic recording. Each subject was also tested with an ERP paradigm where standard (95%, 1000Hz), high deviant (2.5%, 1250Hz) and low deviant (2.5%, 1050Hz) tones were presented. Subjects were asked to ignore the stimuli and read during the task. Mismatch negativity (MMN) and P3a amplitudes and latencies were measured. No between-group difference was observed for sleep stages, except a lower percentage of rapid eye movement (REM) sleep in patients with OSAS (p<0.01). Moreover, the OSAS group showed a higher micro-arousal index and more sleep transitions than the control group (p<0.05). A significant group effect was found for the amplitude of the P3a component (p<0.05) that was lower in patients with OSAS for both high and low deviant tones. No between-group difference was found for the MMN and the P3a latencies. In conclusion, patients with OSAS have specific alterations of the P3a component that reflects involuntary attention switching, but automatic auditory processing assessed by MMN appears to be preserved.

Does age worsen EEG slowing and attention deficits in obstructive sleep apnea syndrome

OBJECTIVE The aim of this study was to determine whether EEG slowing is more pronounced in older than younger OSAS patients and to verify whether this cortical slowing is correlated to daytime performance, respiratory perturbation and sleep fragmentation. METHODS Twelve young OSAS patients (mean age 38.2+/-2.0 y) and 13 older OSAS patients (mean age 62.2+/-1.9 y) along with 13 young controls (mean age 35.8+/-2.0 y) and 14 older controls (mean age 60.2+/-2.0 y) underwent a polysomnographic evaluation followed by a waking EEG recording. As a global index of cortical slowing, a ratio of slow-to-fast frequencies was calculated in all cortical regions. Daytime performance was assessed using the four choice reaction time test. RESULTS Differences in waking EEG and in daytime performance were analyzed by ANOVAs with Group and Age as factors. Waking EEG did not yield a Group by Age interaction. OSAS patients had higher ratios across all regions than controls. Similarly, daytime performance revealed no Group by Age interaction. However, OSAS patients showed more lapses than controls and older subjects were slower than younger subjects. CONCLUSIONS Our results indicate that age does not interact with OSAS to worsen the severity of cortical slowing, but age can add to the OSAS effect to worsen daytime performance deficits in OSAS patients. SIGNIFICANCE The daytime performance deficits observed particularly in elderly OSAS patients warrant a careful clinical assessment of these patients to prevent accidents and injuries.

Accuracy of the Oxford Sleep Resistance Test versus SimultaneousElectroencephalography to Detect Sleep Onset

Background: The Oxford Sleep Resistance test (OSLER) is a useful tool to assess daytime vigilance. However, it has not been validated against simultaneous electroencephalography (EEG) recordings in large populations. The main objective of the study was to compare the OSLER values versus EEG-determined Sleep Onset latency (EEGSOL). Methods: Patients referred for assessment of daytime vigilance were recruited from a tertiary sleep clinic. Patients underwent the OSLER (4 x 40 minutes trials; if 7 consecutive stimuli are missed, the trial is terminated and sleep onset is concluded to have occurred) with simultaneous EEG recordings. Determination of EEG-SOL using American Academy of sleep Medicine (AASM) criteria to score sleep during daytime testing was compared to OSLER values. Results: 65 OSLER were performed in 65 subjects for a total of 260 trials (65X4 trials/OSLER). In 136 out of the 260 trials (52.3%), subjects remained awake according to the OSLER, while EEG-SOL was scored in 5 of the 136 trials (3.7%). Of the 124 trials (47.7%) with sleep onset, (i.e. 7 consecutive missed stimuli) the mean sleep onset value was 14.5 ± 10.9 min and EEG-SOL was recorded before the end of the trial in 37 trials (29.8%) (Mean difference EEG-SOL vs. OSLER 4.1 ± 5.8 min). Conclusion: Using current AASM criteria for daytime testing, EEG-determined sleep onset latency is unlikely to occur in subjects with no sleep onset in the OSLER. However, the presence of sleep onset in the OSLER cannot be used as a precise surrogate to detect EEG sleep onset.

T-I-074 SLEEP ILLNESS REPRESENTATION AS A POTENTIAL BARRIER TO TREATMENT ADHERENCE IN OBSTRUCTIVE SLEEP APNEA: A PILOT STUDY

Introduction and Objectives: Sleep apnea is a chronic disease with severe comorbidities and CPAP adherence is often suboptimal. Behavioral strategies have been shown to help patients accept their disease and encourage them to seek medical attention. Patient perceptions (e.g. cognition, emotion) are viewed as psychological correlates amenable to intervention. The impacts of these perceptions in sleep apnea remain unexplored. The aim of our study was to assess the patient’s sleep illness perceptions and to correlate them to the level of sleepiness, a determinant of disease severity and of CPAP adherence, in patients investigated for sleep apnea. Materials and Methods: Eleven patients (56±14 years; seven men) participated in our study. Sleepiness was measured by the ESS and illness representation by the Brief Illness Perceptions Questionnaire (BIPQ). Questionnaires were filled after the sleep studies. Elevated scores suggest a negative impact in the patient’s life. Results: In terms of cognition, our results suggest that patients believe they will live with the disease all their lives (8/10) and had a low perception of future treatment efficacy (4/10). In terms of emotion, they feel negatively affected by their illness (6.5/10) and their understanding for the latter is rather low (4.5/10). The results of the BIPQ (mean of 6/10±1) and the ESS (11/24±6) correlated positively (r=0.5, p=0.1). We also observed that patients without pathological sleepiness (6 patients, ESS 7/24±3) had better results on the BIPQ (4.6±7.6) compared to those with pathological sleepiness (ESS 16/24±5; BIPQ 5.5±9) (T-test p=0.01). Conclusion: Our study suggests that sleep illness perceptions are interesting avenues to understanding the coping behaviour of our patients and possibly treatment adherence. Further studies are needed to confirm these findings in patients with diagnosed and treated sleep apnea. Acknowledgements: Biron Soins du Sommeil for their constant support