The CCAS-Scale in Chiari Malformation Type I: A Cerebellar-Focused Cognitive Assessment with Clinical Utility.

BACKGROUND/

OBJECTIVES

The Cerebellar Cognitive-Affective Syndrome (CCAS) scale, introduced by Schmahmann, was prospectively administered to 73 symptomatic Chiari malformation type I (CM1) patients (17 pediatric) to assess cerebellar contribution to cognitive-affective dysfunction and evaluate the utility of a cerebellar-focused screening tool.

METHODS

CCAS was categorized as possible (1 failed test), probable (2 failed tests), or definite (≥ 3 failed tests). CCAS total and subtest scores were correlated with baseline symptoms (n = 73) and standard neuropsychological batteries (WAIS, PROMIS, D-KEFS, WRAT, and CVLT, n = 34) using Pearson product-moment correlation with Bonferroni correction. General-linear- model ANOVAs evaluated CCAS diagnostic categories and postoperative outcomes (Chicago-Chiari-Outcome Scale, n = 43).

RESULTS

Definite CCAS was identified in 44% of patients (53%pediatric, 41%adult), with Digit Span Forward showing the highest failure rates and no differences between surgical and non-surgical cohorts. Higher CCAS scores (less impairment) correlated with lower emotional distress (r=-0.34, p < 0.05) and fewer non-pain symptoms. In adults, CCAS scores correlated with broad intellectual, academic, and executive measures (WAIS, WRAT, D-KEFS) but not specific domains, i.e. verbal learning and memory (CVLT). Impairment in CCAS executive and memory domains predicted improved postoperative CCOS total (F = 4.40,p = 0.043), functional (F = 5.24,p = 0.028), and complication scores (F=6.42, p=0.0155).

CONCLUSIONS

Definite CCAS was present in nearly half of patients, supporting a cerebellar contribution to CM1-associated cognitive-affective symptoms. The CCAS scale predicted postoperative outcomes in non-pain domains and captured cognitive brain processing within a network that aligns with established neuropsychological instruments. These findings support CCAS as a valid complementary cognitive assessment tool, with the key distinction that it is designed to detect cognitive dysfunction originating from the cerebellum.