A randomized, wait-list controlled pilot trial has shown efficacy of HIRREM for relieving symptoms of insomnia (Tegeler et al. 2012), and a placebo-controlled trial testing efficacy for migraine has been completed. Changes in
temporal lobe EEG asymmetry associated with use of HIRREM as an intervention for insomnia We present changes in temporal lobe asymmetry for 19 subjects enrolled in a randomized, wait-list, Inhibitors,research,lifescience,medical controlled pilot trial of HIRREM as an intervention for insomnia. Methods and main clinical outcomes for this study have been reported elsewhere (Tegeler et al. 2012). Mean age of subjects was 45 (70% women), and at baseline, mean score on the Insomnia Severity Index (Bastien et al. 2001) was 18.8, indicating, on average, clinical insomnia of moderate severity. Subjects also reported Inhibitors,research,lifescience,medical substantial depressive symptomatology (average CES-D score 14.9). All subjects underwent an average of nine (range 8–13) HIRREM sessions, beginning either immediately after enrollment into the study or after Inhibitors,research,lifescience,medical a waiting period (usual care) of 6 weeks. At the primary endpoint, subjects undergoing HIRREM reported a reduction of 10.3 points in the ISI, while those undergoing usual care reported no change. Though HIRREM exercises were conducted at the temporal,
occipital, parietal, central, and frontal lobes, and anterior and posterior midline, temporal lobes were chosen for the present analysis
on an a priori basis, because of the proximity of the insula and limbic structures related to autonomic functioning (see High-resolution spectral analysis of electroencephalic Inhibitors,research,lifescience,medical data and dynamic, iterative engagement of dominant frequencies). Data for calculation of asymmetry scores were derived from the HIRREM exercise conducted at the bilateral temporal lobes, for each research subject and for each session. For those sessions in which two exercises were conducted at the temporal lobes, the first Inhibitors,research,lifescience,medical exercise was used for calculation Isotretinoin of the asymmetry score. Asymmetry scores were calculated based on the log of the average spectral power (23–36 Hz) at T4 over the course of the 8-min HIRREM exercise, minus log of the average spectral power (23–36 Hz) at T3. The high frequency (23-36 Hz) range of the EEG was chosen for the present analysis because of evidence of high-frequency arousal as being contributory to insomnia (Perlis et al. 2001; Wolynczyk-Gmaj and Szelenberger 2011). Figure 4 shows the average asymmetry score for T3 in comparison with T4, for all 19 subjects over the course of their HIRREM sessions. Rightward asymmetry (T4 > T3) diminished over the course of six HIRREM sessions, followed by a shift to average leftward asymmetry (T3 > T4) for session 7, and a return to rightward asymmetry for session 8.