Predecompression and postdecompression cognitive and affective changes in Chiari malformation type I

OBJECTIVE The role of the cerebellum in cognitive function and psychiatric symptoms is poorly understood and particularly understudied in patients with cerebellar pathologies such as Chiari malformation type I (CM-I). Additionally, it is unclear if interventions targeted toward the cerebellum might impact these life-altering symptoms. The authors sought to characterize pre- and postoperative cognitive and psychiatric function in CM-I patients as evidence for targeted cerebellar treatment for some cognitive and psychiatric conditions. METHODS This prospective study included surgical patients with CM-I who reported cognitive or psychiatric dysfunction. Patients completed a preoperative assessment and a parallel assessment 6 months following surgery. Neuropsychological evaluations included a 90-minute standardized assessment of cognitive function across multiple domains and a self-reported assessment of psychiatric symptoms. This clinical sample consisted of 54 patients (mean age 34.17 years, median 14.15 years). Any patient demonstrating preoperative performance below 3.5 SDs within any cognitive domain was excluded (n = 1). All patients underwent preoperative neuropsychological assessment comprising standard clinical tests of processing speed, attention, memory, executive function, and psychiatric symptoms. RESULTS Preoperatively, CM-I patients performed significantly worse than a representative normative sample on measures of executive function and visuospatial memory and reported more psychiatric symptoms across all domains. On postoperative assessment, 89% of patients showed clinically significant improvements (> 1 SD) in cognitive and/or psychiatric domains. CONCLUSIONS The authors demonstrate significant, often unrecognized, impairments in cognitive function and psychiatric symptoms in a cohort of CM-I patients. Following targeted surgical posterior fossa decompression, these symptoms improved, suggesting that at least in a subgroup of symptomatic CM-I patients, these symptoms may be treatable. This study highlights the potential role of the cerebellum in cognitive and psychiatric dysfunction.