Elevated Plasma Prolactin and EEG Slow Wave Power in Post-Polio Fatigue

To test the hypothesis that plasma prolactin and clcc-troencephalographic (EEG) slow wave activity are correlated with fatigue, 33 polio survivors without medical or psychologic comorbid-ities were studied. Subjects were administered the Post-Polio Fatigue Questionnaire (PFQ) and had resting measurement of both plasma prolactin and bilateral temporal-occipital power across the EEG frequency spectrum. Typical daily fatigue severity on the PFQ was significantly correlated with daily difficulty with attention, staying awake and motivation, but not with measures of acute polio severity or the number of limbs affected by laie-onset Post-Polio Sequelae symptoms. Prolactin was significantly correlated with daily fatigue severity on the PFQ (r = .39; p < .05). EEG power was equal between the two hemispheres across all frequency bands. However, EEG slow wave power in the right hemisphere was significantly correlated with daily fatigue severity and prolactin level (r = .37; p < .05). Using multiple linear regression, age at acute polio, frequency of difficulty with attention on the PFQ, prolactin and right hemisphere slow wave power predicted 72% of the variance of the daily fatigue severity rating (r = .85; p < .0001). These data suggest that increased prolactin secretion and EEG slowing are related to the severity of post-polio fatigue, findings similar to those in patients with acute paralytic and non-paralytic poliomyelitis and with chronic fatigue syndrome. A primary role is suggested for a dopamine deficiency (versus serotonergic receptor supersensitivity) underlying impaired cortical activation and the symptoms associated with putative post-viral fatigue syndromes.