Hidden impacts, visible deficits: a comprehensive systematic literature review of the cognitive impairment in patients with Chiari malformation type I.
Review
Overview
abstract
This systematic review aims to examine the relationship between Chiari Malformation Type I (CM-I) and cognitive impairment, with particular attention to five key research questions: (1) the association between the degree of tonsillar ectopia and cognitive deficits; (2) the mediating role of chronic pain and psychological comorbidities; (3) the relationship between diffusion tensor imaging (DTI) metrics and cognitive dysfunction; (4) the reversibility of microstructural abnormalities and associated cognitive changes following decompression surgery; and (5) whether cognitive impairment alone may justify surgical intervention.Following PRISMA 2020 guidelines, a systematic review of the Medline/PubMed database was conducted for studies reporting on adult CM-I patients with cognitive assessments between 2000 and 2025. The extracted data included demographics, clinical and radiological characteristics, surgical status, cognitive domains affected, and the cognitive assessment tools used.Nineteen studies involving 1,226 patients were included. Cognitive impairments were frequently observed, particularly in processing speed (42.1%), visuospatial capacity (42.1%), attention (36.8%), and executive function (36.8%). Only four studies included both pre- and postoperative cognitive assessments, yielding mixed findings on the benefits of surgery. DTI studies revealed microstructural abnormalities in several white matter regions, some of which correlated with cognitive deficits. Pain and psychological distress were shown to influence memory and processing speed, but attention and executive deficits appeared independent of these factors. Functional and structural imaging data suggest widespread neuroanatomical disruption beyond the cerebellum and brainstem.Neurocognitive dysfunction in CM-I is multifactorial, involving structural abnormalities, chronic pain, and psychological comorbidities. While decompression surgery improves anatomical and symptomatic outcomes, its cognitive benefits remain inconsistent and domain-specific. Cognitive deficits alone may not suffice as a sole surgical indication.
