The Cerebellar Cognitive Affective/Schmahmann Syndrome: a Task Force Paper

Abstract

Sporadically advocated over the last two centuries, a cerebellar role in cognition and affect has been rigorously established in the past few decades. In the clinical domain, such progress is epitomized by the "cerebellar cognitive affective syndrome" ("CCAS") or "Schmahmann syndrome." Introduced in the late 1990s, CCAS reflects a constellation of cerebellar-induced sequelae, comprising deficits in executive function, visuospatial cognition, emotion-affect, and language, over and above speech. The CCAS thus offers excellent grounds to investigate the functional topography of the cerebellum, and, ultimately, illustrate the precise mechanisms by which the cerebellum modulates cognition and affect. The primary objective of this task force paper is thus to stimulate further research in this area. After providing an up-to-date overview of the fundamental findings on cerebellar neurocognition, the paper substantiates the concept of CCAS with recent evidence from different scientific angles, promotes awareness of the CCAS as a clinical entity, and examines our current insight into the therapeutic options available. The paper finally identifies topics of divergence and outstanding questions for further research.

Altered Cerebellum Spontaneous Activity in juvenile Autism Spectrum Disorders Associated with Cognitive Functions

“…The present ndings about the role of cerebellum subregions in cognitive function were in accordance with previous studies. Clinical study has con rmed that patients with cerebellum lesions might experience cerebellar cognitive affective syndrome (Argyropoulos, et al, 2020). The abnormal cerebellum activity has also been found in other disease with cognitive impairment such as Parkinson's Disease (Solstrand, et al, 2020).…”

Replicability, repeatability, and long-term reproducibility of cerebellar morphometry

“…A 3-dimensional high-resolution and high-contrast T1-weighted magnetization prepared rapid gradient echo (MPRAGE) sequence was used (26). Imaging parameters were: TR (repetition time; between two successive inversion pulses): 2000 ms, TE (echo time): 2.07 ms, TI (inversion time): 952 ms, flip angle: 9°, isotropic voxel size: 0.75 × 0.75 × 0.75 mm 3 , 224 sagittal slices, k-space interpolation-based in-plane acceleration (GRAPPA) with an acceleration factor of 2 (27), time of acquisition: 6:16 min. Siemens' prescan normalization filter was used for online compensation of regional signal inhomogeneities.…”

“…For a detailed description of the entire study, see (28). The data set is publicly available for download 3 and has been used in several studies on the reproducibility of MRI analyses (e.g., (29,30)). MR images of the entire brain were acquired at 3 Tesla using a Philips Achieva MR scanner (Philips Healthcare, Best, The Netherlands) with an 8-channel receive-array head coil.…”

“…were: TR (between two successive gradient echoes): 9.7 ms, TE: 4 ms, TI 20 ms, flip angle: 10°, voxel size: 1 × 1 × 1.25 mm 3 , 128 sagittal slices.…”

Autism Spectrum Disorders and Ataxia

“…Some SCAs are considered pure cerebellar ataxias as degeneration is largely confined to the cerebellum (i.e., SCA5, SCA6, SCA11), while others have more pervasive degeneration in other brain regions or other parts of the central nervous system (i.e., SCA3, SCA7) (Paulson 2009). Deficits in executive function, memory, attention, and Theory of Mind have been identified in subjects with SCAs (Argyropoulos et al 2020;Burk et al 2001Burk et al , 2003Globas et al 2003;Kawai et al 2004;Garrard et al 2008;Hoche et al 2016Hoche et al , 2018. These impairments mirror deficits in autism and provide further evidence of the cerebellar involvement in processing cognitive and emotional functions.…”