EEG Power Spectral Analysis Research Articles

Spectral analysis of EEG differences between children with and without learning disabilities.

Power Spectral Fast Fourier analysis of the scalp EEG was obtained from six locations, three left hemisphere and three right hemisphere, in 69 children with learning disabilities without hyperactivity and 34 control children, during baseline and while performing reading, arithmetical and spatial tasks in their schools. Significant EEG power and percent differences for specific frequencies were obtained between groups. The ability to predict attention deficit or control status was high based upon discriminant analysis for these subjects. The possibility for the supplementation of existing psychometrics with a neurometric based on power analysis of the EEG is discussed.

EEG states of the brain, information processing, and schizophrenic primary symptoms

The electroencephalographic (EEG) reactivity to auditory information (the central component of the orienting reaction) was used to examine brain states underlying information processing in acute and recovered medication-free schizophrenics and matched controls. EEG reactivity was assessed as information-induced changes of parameters extracted from power spectral frequency analysis of the ongoing EEG. EEG reactivity in controls and schizophrenics in remission was largely similar. Acute schizophrenics showed a deviant (ectropic) reactivity, which consisted of changes within the 2–8 Hz band, and of either severely reduced or absent response in the 8–13 Hz (alpha) band. These results indicate an ectropic brain state during cognitive processing of received information during the period of acute schizophrenic symptomatology.

Electrophysiological profile of neurotropics (hydergine, piracetam, pyritinol) in organic brain disease in the aged

AbstractZimmermann, P., E.W. Füfgeld, R. Seidel, and W. Nischwitz: Electrophysiological profile of neurotropics (hydergine, piracetam, pyritionol) in organic brain disease in the aged. Drug Dev. Res. 2:481–488, 1982.The effects of neurotropics on brainstem and cortical neuronal activity were compared between three groups of patients suffering from chronic brain disease (arteriosclerotic or senile dementia). Hydergine (6–9 mg/day), piracetam (1,200 mg/day), or pyritinol (600 mg/day) were administered orally for 8wk. EEG power spectral analysis, visual evoked potentials (VEP) and bink reflexes were performed after an initial wash‐out period of 2 wk, 2 and 8 wk of neurotropic medication, and a final wash‐out period of 2 wk. EEG power spectra following hyderine show a significant decrease in slow alpha activity (7.5–10 Hz) and after pyritinol in the slow theta range (3–5 Hz) in the occipital region. In the piracetam group the power of the fast theta (5–7.5 Hz) and slow alpha activity decrease in the occipital region of the dominant hemisphere. Only during pyritinol medication do these signs of cerebral activation correlate with an increase in the amplitude of P350 of VEP and of the R2 component of the blink reflex.

Power spectral analysis of EEG drug response in the kindled rat brain

The specificity of procaine as a limbic epileptic focus activator was investigated in rats kindled in the amygdala. Power spectral analysis of spontaneous EEG was employed to assess the effects of two doses of procaine HCl (60 and 100 mg/kg) on the kindled and unkindled amygdala. Analysis revealed a dose-dependent increase in power in the 1–15 c/sec frequency band of the EEG. Power increases were greater in the kindled than in the unkindled amygdala of the same rat, and exceeded power changes induced in unkindled controls. The effects of procaine on the EEG persisted past the day of injection, but returned to baseline by the fifth day. Changes in power over days following an injection of procaine differed in the kindled and unkindled amygdala of the same rat. The kindled amygdala showed an increase on the day of injection, followed by a steady decline to baseline. The unkindled amygdala showed a delayed rise in power on day 2 and then a decline to baseline levels over days. Comparison of spectral changes induced by drug and by electrically triggered seizures suggested that procaine induces EEG patterns which are seizure-like in the absence of seizures. The data are consistent with the view that procaine may be a useful focus specific activator in the detection of limbic epilepsy.

Quantitative EEG and behavioral effects in volunteers of a new benzodiazepine (SAS 643) in relation to drug plasma concentration.

EEG (power spectral analysis) and behavioral effects of single, 5 to 20 mg doses of SAS 643, a newly developed benzodiazepine, were defined in normal male volunteers in relation to drug plasma concentration. A single 20 mg dose of SAS 643 induced an increment in power of fast frequency components (above 16.5 Hz), predominant on posterior leads, and paralleled by a decrement in the 4.5-8 Hz power. A concomitant increase in 0.5-4 Hz power and decrease in 8.5-12 Hz power were also evident in anterior scalp areas. EEG effects were less systematic following the administration 10 mg, and only occasional at the 5 mg dose. These EEG modifications are qualitatively consistent with the profile of antianxiety compounds, relative to dose and their ongoing time parallels SAS 643 plasma concentration, though the EEG/plasma level correlation was not statistically significant across subjects, due to individual variability. Systematic effects were not observed in any of the behavioral or neuropsychological variables considered. SAS 643 bioavailability and action at the central nervous system (CNS) level is established. The results exemplify the routine applicability of pharmaco-EEG procedures. The topographic differences in SAS 643 EEG effects warrant systematic studies on the issue.

Hypersomnia with simultaneous waking and sleep patterns in the electroencephalogram

A mildly dyslexic boy of 11 years, with no neurological deficit or history of epileptic seizures, had marked hypersomnia for 2 years, which was most pronounced in the morning hours. Repeated EEG studies and power spectral analysis revealed simultaneous posterior alpha rhythm and sleep patterns (spindles, vertex waves, K complexes) over vertex and frontocentral regions, while the patient was behaviorally awake. Bilateral synchronous anterior spikes were frequently noted in association with sleep patterns. A polysomnogram over 24 h confirmed excessive sleep, night and day (especially morning hours) and there was evidence of a large REM sleep percentage (on EMG and EOG basis) while the EEG had predominantly non-REM sleep patterns. Special neurotransmitter studies were performed in view of a presumed disturbance affecting the neurobiochemical sleep regulation. These studies were based on CSF metabolite levels and provided evidence for a high serotonin metabolite (5HIAA) level. It is tempting to hypothesize that the biochemical disturbance has led to encroachment of non-REM sleep patterns on both wakefulness and REM sleep. Further discussion deals with the bilateral-synchronous spike activity and its relationship to arousal patterns in sleep.

Visual and somatosensory evoked potential characteristics of patients undergoing hemodialysis and kidney transplantation

The effects of prolonged hemodialysis and kidney transplantation on visual and somatosensory evoked potentials and EEG frequency were assessed. Significant changes were found in both amplitude and latency characteristics of evoked potentials recorded from eight hemodialysis patients. Their evoked potentials tended to be of longer latency and larger amplitude when compared to responses of an age-matched control group. This was true for visual and somatosensory responses recorded from several scalp locations. A correlational analysis revealed no consistent relationship between blood chemistries and evoked potential characteristics. EEG power spectral analysis showed that the dominant frequency of five of the eight dialysis patients was in the 8–10 c/sec range. Two other patients demonstrated EEG frequencies which were scattered across the 3–12 c/sec range while for another subject the dominant frequency was 7–8 c/sec. The evoked potential latencies and amplitudes of patients with successful kidney transplant tended to return to the normal range and their predominant EEG frequency increased to around 10 c/sec. A depression of function in those neural systems underlying the visual and somatosensory modalities, along with a reduction in the cortical suppression of afferent stimulation normally exerted by the thalamic reticular system and the basal ganglia were postulated to account for the reported findings.

EEG Operant Conditioning in a Monkey Model: II. EEG Spectral Analysis

EEG power spectral analysis was studied from 14 (alumina-gel) chronically epileptic, undrugged monkeys during an EEG operant conditioning experiment. The composite profile of the average epileptic monkey shows the majority of power to be below 10 Hz. Because of the large variance in the data, no significant changes in the EEG power spectra could be detected as a function of conditioning. The possible reasons for this large variance are discussed. Hypothesis from previous human "biofeedback" studies would allow the prediction that those frequencies corresponding to the mu and sensory-motor-rhythm should negatively covary with seizure frequency. Data from this study did not support such assertions. The method of using spectral analysis for quantifying changes in the EEG which covary with operant conditioning is evaluated.

EEG power spectral changes secondary to L-DOPA treatment in parkinsonian patients: a pilot study

Clinical EEG evaluation and power spectral analysis were performed on 12 parkinsonian patients before and during L-DOPA treatment. The EEG evaluation did not disclose any significant effects of L-DOPA treatment. Spectral analysis disclosed normal interlobar and interhemispheric power differences and an increase in delta and slow-theta power in the right temporal as compared to the right occipital lobe before L-DOPA treatment was initiated. L-DOPA treatment significantly increased alpha power in both occipital lobes, decreased theta power in the right temporal lobe, accentuated power differences in the theta and alpha bands between temporal and occipital lobesand attenuated beta power differences in those areas. This work is intended as a pilot study in the quantitative EEG evaluation of Parkinson's disease and L-DOPA treatment.

EEG power spectral analysis of newborn infants' sleep states : A. H. Parmelee (Los Angeles, Calif., U.S.A.)

EEG power spectral analysis of newborn infants' sleep states : A. H. Parmelee (Los Angeles, Calif., U.S.A.)