ANXIETY AND EEG ALPHA ACTIVITY IN NEUROTIC PATIENTS

The literature is reviewed on EEG alpha activity in different psychological states, i.e., morbid anxiety, attention and mental relaxation. In the present study, 20 male neurotic inpatients suffering from chronic moderate anxiety were assessed with respect to anxiety level and EEG alpha activity (frequency and per cent time) and fast activity. No significant EEG asymmetry was found. The average alpha per cent time was very low, most of the patients being low-alpha subjects. Anxiety and alpha index were significantly correlated. The patients were then treated with either 80 mg per day of temazepam or placebo for 2 weeks (double-blind). Significant effects were detected in the anxiety state, the drug group showing more improvement, but not in the EEG profile. The measures were expressed at this stage as change scores from the pre-treatment values and correlations between them were computed. The only correlation of significance was a negative correlation between anxiety level and alpha index found after 1 week in the drug group.     

COVARIATION OF SPECTRAL AND NONLINEAR EEG MEASURES WITH ALPHA BIOFEEDBACK

This study investigated how different spectral and nonlinear EEG measures covaried with alpha power during auditory alpha biofeedback training, performed by 13 healthy subjects. We found a significant positive correlation of alpha power with the largest Lyapunov-exponent, pointing to an increased dynamical instability of the EEG accompanying alpha enhancement. Alpha power amplification, moreover, was significantly correlated with a decrease of spectral entropy within the alpha range. This outcome reflects a sharpening of the alpha peak during biofeedback training. The fact that the sharpening effect clearly preceded the increase of alpha amplitude could be exploited in future biofeedback settings.     

AUDITORY ON- AND OFF-RESPONSES AND ALPHA OSCILLATIONS IN THE HUMAN EEG

In the present study, the wide band alpha and sub-bands of alpha in the auditory on- and off-responses to different stimulation frequencies were evaluated. Auditory on- and off-responses of 12 healthy volunteers (average 17 years old) were recorded from five locations (Fz, Cz, Pz, P3, and P4). The auditory stimuli of 80 dB SPL and 1000 ms duration were delivered at six different stimulation frequencies (f1-f6; 0.2, 0.6, 1, 2, 3, and 4 kHz, respectively). In using individual alpha frequency (IAF) as individual anchor point, wide band alpha and three different alpha frequency sub-bands with a bandwidth of 2 Hz each were defined: lower-1 alpha, lower-2 alpha, and upper alpha. The Root Mean Square (RMS) values of the alpha frequency bands were computed for two time periods: ± 3 sd around the mean peak latency of the auditory on-responses (t1-on and t2-on) and a time window of the same length of the auditory off-responses (t1-off and t2-off). The alpha RMS values of both on- and off- responses showed significant differences between t1 and t2 periods on wide band, lower-1 and lower-2 alpha bands, especially at 0.2, 0.6, 1, 2, and 3 kHz stimulation frequencies in all recording places. Amplitudes in anterior locations (Fz, Cz) were higher than the others. These observations may provide a preliminary but nonetheless important understanding of how information may be processed in the brain.     

ALPHA EEG PREDICTS VISUAL REACTION TIME

Studies have suggested that consciousness is encoded discretely in time and synchronously in space of the brain. The present study was to model the alpha EEG as a brain clock to carry out the functions and to test whether the quality and rate of the oscillation could predict behavioral timing. Results showed that the alpha peak frequency was correlated with the conflict reaction time, and the selectivity was associated with the simple reaction time. These findings are consistent with previous reports and support the hypothesis that alpha EEG represents excitability cycles and may serves as a brain clock for spatial synchronization.     

TOWARD THE APPLICATION OF FUNCTIONAL NEUROIMAGING TO INDIVIDUALIZED TREATMENT FOR ANXIETY AND DEPRESSION

Functional neuroimaging has led to significant gains in understanding the biological bases of anxiety and depressive disorders. However, the ability of functional neuroimaging to directly impact clinical practice is unclear. One important method by which neuroimaging could impact clinical care is to generate single patient level predictions that can guide clinical decision‐making. The present review summarizes published functional neuroimaging studies of predictors of medication or psychotherapy outcome in major depressive disorder, obsessive‐compulsive disorder (OCD), posttraumatic stress disorder, generalized anxiety disorder, panic disorder, and social anxiety disorder. In major depressive disorder and OCD, there is converging evidence of specific brain circuitry that has both been implicated in the disordered state itself, and where pretreatment activation levels have been predictive of treatment response. Specifically, in major depressive disorder, greater pretreatment ventral and pregenual anterior cingulate cortex (ACC) activation may predict better antidepressant medication outcome but poorer psychotherapy outcome. In OCD, activation in the ACC and orbitofrontal cortex has been inversely associated with pharmacological treatment response. In other anxiety disorders, research in this area is just beginning, with the ACC potentially implicated. However, the question of whether these results can directly translate to clinical practice remains open. In order to achieve the goal of single patient level prediction and individualized treatment, future research should strive to establish replicable models with good predictive performance and clear incremental validity.     

AGE-RELATED CHANGES IN NEOCORTICAL HIGH-VOLTAGE SPINDLES AND ALPHA EEG POWER DURING QUIET WAKING IN RATS

Age-related changes in neocortical high-voltage spindle (HVS) and in electroencephalographic (EEG) alpha power were examined in young (3.0 to 4.6 months), middle -aged (10.2 to 13.8 months), and old (21.5 to 24.0 months) male Wistar rats during quiet waking. Whereas the duration of quiet waking stage did not change as a function of age, a significant increase in HVS amount and EEG alpha peak power was observed in the middle-aged rats with only a tendency for a further enhancement in the old animals. An additional analysis showed that the elevation of alpha power is associated with age rather than with HVS activity.     

LINE BISECTION TASK PERFORMANCE AND RESTING EEG ALPHA POWER

Neurologically normal subjects generally err to the left of veridical center when performing a line bisection task, a phenomenon termed "pseudoneglect." We hypothesized that resting electroencephalogram (EEG) alpha oscillations may show relationships with attentional mechanisms and give some clues about the underlying mechanisms of pseudoneglect. We recorded resting EEGs of 4l subjects and tested them with a paper-pencil line bisection task. Our results showed that line bisection scores of men (n = 18) were less biased and their performance was higher compared to those of women (n = 20), but these differences only approached significance. The eyes open resting EEG alpha power of women was significantly and positively correlated with their line bisection performance. In general, significant relationships were related to the left hand performance when the lines were presented in the left hemispace. Greater resting alpha power was correlated with lower absolute bisection score or, in other words, higher bisection performance. Greater alpha power also correlated with diminished leftward bisection bias (or reduced pseudo -neglect). The resting EEG alpha of men was weakly associated with bisection performance. Results discussed in terms of Kinsbourne's activation-orientation theory and Basar's view on brain oscillations.     

OXPRENOLOL IN THE TREATMENT OF MIGRAINE

Thirty migraine patients received oxprenolol (Trasicor), which is an adrenergic beta-receptor blocking agent with weak beta-stimulating intrinsic activity. The dosage was 80 mg three times a day. The treatment was given by a double blind cross-over technique in which the effect was compared with placebo. Each compound was administered for 8 weeks with an intermediate week without medication (wash-out). Oxprenolol had no significant effects in the prevention of migraine attacks. Our study lends further support to the assumption that differences may exist between different beta-receptor blocking agents in their effectiveness in migraine prophylaxis.     

DRUG TREATMENT OF HYPERACTIVITY IN CHILDREN

Recently-developed quantitative reviewing procedures were applied to 61 selected studies in order to explore the efficacy of pharmacological management for children identified as hyperactive. Analysis of effect-size information derived from the studies revealed that the average child receiving drug treatment was less hyperactive than 88.5 per cent of the control children. 30 per cent of this effect could be attributed to placebo phenomenon. The analysis also indicated that drug therapy had the most pronounced effect on dependent variables consisting of standardized or informal measures of behaviour and the least effect on measures of IQ and academic achievement. The advantages of quantitative reviewing methodology for adding clarity and consensus to complex bodies of literature are demonstrated and discussed.