Cognitive impairments during the acute phase of bacterial brain abscess and long-term neuropsychological profiles: a case series study.

Introduction: A bacterial brain abscess (BA) is a localized cerebral infection that requires prompt neurosurgical intervention, although the implementation of treatment may take several days. Approximately half of BA patients exhibit neurological signs, while less is known about cognitive abnormalities following BA from the acute to chronic phases. This case series study aimed to investigate cognitive impairments in patients with BA during the acute phase and evaluate post-acute selective cognitive deficits that align with BA location in neuropsychological profiles during the first year following neurosurgery.

Methods: A case series study of six patients with BA (ages 24-71, 50% female) who underwent neuropsychological evaluations during admission to the neurosurgical department (acute phase), at 8 weeks (subacute phase) and 1 year (chronic phase) post-neurosurgery. Acute phase cognitive impairments were considered as at least two z-scores ≤-1.50 in a brief test battery assessing language, attention, memory, psychomotor speed, and executive functions. Post-acute selective cognitive deficits were considered in a comprehensive test battery as discrepancies aligning with BA location between verbal vs. visual intellectual functions, memory, and attention, as well as right vs. left motor speed functions, of ≥2 SD between or alpha level < .05 using WAIS-IV software.

Results: Five cases had cognitive impairments during the acute phase, whereof three had lateralized neurological deficits (e.g. homonymous hemianopsia, hemiparesis). Four cases had selective cognitive deficits both at 8 weeks and 1 year.

Conclusions: BA patients may exhibit cognitive impairments during admission to acute medical care despite having normal neurological status. A brief neuropsychological test battery should be considered in the post-surgical treatment of BA patients to assist in patient management and planning. Selective cognitive deficits may be a long-term consequence of BA. This study highlights the cognitive impact of BA and illustrates the necessity of expediting the diagnostic process and treatment.