Faculty Bibliography

Emotion attribution (EA) from faces is key to social cognition, and deficits in perception of emotions from faces underlie neuropsychiatric disorders in which cerebellar pathology is reported. Here, we test the hypothesis that the cerebellum contributes to social cognition through EA from faces. We examined 57 patients with cerebellar disorders and 57 healthy controls. Thirty-one patients had complex cerebrocerebellar disease (complex cerebrocerebellar disease group (CD)); 26 had disease isolated to cerebellum (isolated cerebellar disease group (ID)). EA was measured with the Reading the Mind in the Eyes test (RMET), and informants were administered a novel questionnaire, the Cerebellar Neuropsychiatric Rating Scale (CNRS). EA was impaired in all patients (CD p < 0.001, ID p < 0.001). When analyzed for valence categories, both CD and ID missed more positive and negative stimuli. Positive targets produced the highest deficit (CD p < 0.001, ID p = 0.004). EA impairments correlated with CNRS measures of deficient social skills (p < 0.05) and autism spectrum behaviors (p < 0.005). Patients had difficulties with emotion regulation (CD p < 0.001, ID p < 0.001), autism spectrum behaviors (CD p < 0.049, ID p < 0.001), and psychosis spectrum symptoms (CD p < 0.021, ID p < 0.002). ID informants endorsed deficient social skills (CD p < 0.746, ID p < 0.003) and impaired attention regulation (CD p < 0.144, ID p < 0.001). Within the psychosis spectrum domain, CD patients were worse than controls for lack of empathy (CD p = 0.05; ID p = 0.49). Thus, patients with cerebellar damage were impaired on an EA task associated with deficient social skills and autism spectrum behaviors and experienced psychosocial difficulties on the CNRS. This has relevance for ataxias, the cerebellar cognitive affective/Schmahmann syndrome, and neuropsychiatric disorders with cerebellar pathology.

The cerebellar cognitive affective syndrome (CCAS) includes disruption of linguistic processing such as verbal fluency, verbal working memory, grammar, and speech perception. We set out to examine linguistic capabilities in patients with cerebellar lesions to determine which domains are spared and which impaired and to evaluate the underlying cognitive structure of these deficits. Forty-four patients with cerebellar disease were compared to 40 healthy controls on the Oral Sentence Production Test (OSPT) which assesses production of sentences with correct syntactic structure and semantic quality. Twenty-five of these cerebellar patients and 25 controls received the Test of Language Competence-Expanded (TLC-E) that assesses metalinguistic ability. The OSPT failed to reveal differences between patients and controls. In contrast, all cerebellar patients were impaired on each of the four TLC-E subtests. Differences between isolated cerebellar and complex cerebrocerebellar patients were nonsignificant. These results confirm and extend prior observations of the TLC-E in patients with cerebellar lesions and suggest three separate but related language impairments following cerebellar dysfunction: (1) disruption in automatic adjustment of intact grammatical and semantic abilities to a linguistic context in sentence production, (2) disruption in automatic adjustment to a linguistic context in sentence interpretation, and (3) disruption of cognitive processes essential for linguistic skills, such as analysis and sequential logical reasoning. These findings are consistent with the unifying framework of the universal cerebellar transform and the dysmetria of thought theory and provide new insights into the nature of the cognitive impairments in patients with the CCAS.