Neuropsychological Characteristics and Quantitative Electroencephalography in Skogholt’s Disease—A Rare Neurodegenerative Disease in a Norwegian Family

Abstract

Members of three generations of a Norwegian family (N = 9) with a rare demyelinating disease were studied. Neuropsychological testing was performed using the Mini Mental Status Examination (MMSE), Wechsler Intelligence Scale-III (WAIS-III), and Hopkins Verbal Learning Test-Revised (HVLT-R). EEGs were recorded with grand averaging spectrograms and event-related potentials (ERPs) in rest and cued GO/NOGO task conditions. The results were within the normal range on the MMSE. Full-scale WAIS-III results were in the range of 69–113, with lower scores in verbal understanding than in perceptual organization, and low scores also in indications of working memory and processing speed difficulties. The HVLT-R showed impairment of both immediate and delayed recall. Quantitative EEG showed an increase in low alpha (around 7.5 Hz) activity in the temporofrontal areas, mostly on the left side. There was a deviation in the late (>300 ms) component in response to the NOGO stimuli. A strong correlation (r = 0.78, p = 0.01) between the Hopkins Verbal Learning Test (delayed recall) and the amplitude of the NOGO ERP component was observed. The EEG spectra showed deviations from the healthy controls, especially at frontotemporal deviations. Deviations in the ERP component of the NOGO trials were related to delayed recall in the Hopkins Verbal learning test.