Regional cerebral blood flow and cognitive deficits in chronic Lyme disease

This study examined brain functioning in patients with Lyme encephalopathy. Eleven patients underwent neuropsychological tests and Xenon (133)-regional cerebral blood flow (rCBF) studies, using an external detector system. Each rCBF scan was age- and sex-matched to two archival, normal controls. While few differences were noted on gray-matter flow indices (ISI, fg), Lyme patients demonstrated significant flow reductions in white matter index (k(2)) (p = .004), particularly in the posterior temporal and parietal lobes bilaterally (p = .003). Flow reductions in white matter areas were significantly associated with deficits in memory (r = .66, p = .027) and visuospatial organization (r = .62, p = .041). Results suggest that Lyme encephalopathy may be a disease primarily affecting the cerebral white matter.