Snr 2001

s of Scientific Presentations Listed Alphabetically by Author/Presenter Peak Alpha Frequency: An Electroencephalographic Measure of Cognitive Preparedness Efthymios Angelakis, PhD candidate University of Tennessee, Knoxville, Tennessee [email protected] Introduction. Electroencephalographic (EEG) peak alpha frequency (PAF) has been shown to correlate with a variety of phenomena, including age, memory performance in healthy and demented individuals, different emotional states, schizophrenia, anxiety, nicotine and caffeine administration, recovery from stroke, cerebral blood flow (CBF) velocity, and brain oxygenation (e.g., Klimesch, Schimke, Ladurner, & Pfurtscheller, 1990; Canive et al., 1998; Kostyunina, 1998; Knott, 1988). Moreover, PAF is increased after acute administration of the mind enhancing drug piracetam (e.g., Kinoshita, 1990). These studies have shown that PAF varies between healthy and clinical individuals, with the latter consistently having lower PAF. Moreover, PAF varies between healthy individuals, reflecting cognitive performance, with better performance being associated with increased PAF. Finally, PAF varies within individuals both between developmental stages and between different cognitive tasks, or physiological states induced by administration of various substances. The present study investigated the hypothesis that among other phenomena PAF reflects a state of cognitive preparedness, using three independent datasets from healthy and brain injured individuals. Based on the preceding literature, the following hypotheses were generated. First, that PAF is an index of optimal brain function, being suppressed under brain pathology (hypothesis #1). Second, that PAF shows cognitive preparedness within individuals, reflecting task performance differences at different days (hypothesis #2). Third, that PAF is increased after tasks more in those individuals who had it lower at initial baseline, being affected by the task that forces them to correct their initial unpreparedness (hypothesis #3). Method. Dataset A involved EEG recordings from 10 individuals with traumatic brain injury (TBI) and 12 healthy age and sex matched controls, before, during, and after tasks of visual and auditory attention (Captain's Log, Brain Train). Dataset B involved EEG recordings from 19 healthy young adults before and after a three-minute working memory task (WAIS-R Digit Span). In this dataset, the procedure has been repeated on two different days, so withinindividual differences in PAF and performance could be measured. Dataset C involved EEG recordings from 15 healthy young adults before, during, and after a set of reading tasks (task duration 5-20 minutes) EEG was recorded at 19 scalp electrodes using the 10/20 international electrode placement system. Average PAF for each recording was reported using the EEG Workstation 2.0 software (NovatechEEG, Inc.). http://www.snr-jnt.org/newspluss/2002/papers2002.htm (1 of 45)12/30/2006 5:48:37 AM