title: Consensus Paper: Revisiting the Symptoms and Signs of Cerebellar Syndrome.
abstract: The cerebellum is involved in sensorimotor operations, cognitive tasks and affective processes. Here, we revisit the concept of the cerebellar syndrome in the light of recent advances in our understanding of cerebellar operations. The key symptoms and signs of cerebellar dysfunction, often grouped under the generic term of ataxia, are discussed. Vertigo, dizziness, and imbalance are associated with lesions of the vestibulo-cerebellar, vestibulo-spinal, or cerebellar ocular motor systems. The cerebellum plays a major role in the online to long-term control of eye movements (control of calibration, reduction of eye instability, maintenance of ocular alignment). Ocular instability, nystagmus, saccadic intrusions, impaired smooth pursuit, impaired vestibulo-ocular reflex (VOR), and ocular misalignment are at the core of oculomotor cerebellar deficits. As a motor speech disorder, ataxic dysarthria is highly suggestive of cerebellar pathology. Regarding motor control of limbs, hypotonia, a- or dysdiadochokinesia, dysmetria, grasping deficits and various tremor phenomenologies are observed in cerebellar disorders to varying degrees. There is clear evidence that the cerebellum participates in force perception and proprioceptive sense during active movements. Gait is staggering with a wide base, and tandem gait is very often impaired in cerebellar disorders. In terms of cognitive and affective operations, impairments are found in executive functions, visual-spatial processing, linguistic function, and affective regulation (Schmahmann's syndrome). Nonmotor linguistic deficits including disruption of articulatory and graphomotor planning, language dynamics, verbal fluency, phonological, and semantic word retrieval, expressive and receptive syntax, and various aspects of reading and writing may be impaired after cerebellar damage. The cerebellum is organized into (a) a primary sensorimotor region in the anterior lobe and adjacent part of lobule VI, (b) a second sensorimotor region in lobule VIII, and (c) cognitive and limbic regions located in the posterior lobe (lobule VI, lobule VIIA which includes crus I and crus II, and lobule VIIB). The limbic cerebellum is mainly represented in the posterior vermis. The cortico-ponto-cerebellar and cerebello-thalamo-cortical loops establish close functional connections between the cerebellum and the supratentorial motor, paralimbic and association cortices, and cerebellar symptoms are associated with a disruption of these loops.
authors.affiliation: FNRS ULB-Erasme, Unité d'Etude du Mouvement, 808 Route de Lennik, 1070, Brussels, Belgium.
authors.forename: Florian
authors.initials: F
authors.lastname: Bodranghien
authors.affiliation: Kennedy Krieger Institute, 707 N. Broadway, Baltimore, MD, 21205, USA.
authors.forename: Amy
authors.initials: A
authors.lastname: Bastian
authors.affiliation: Department of Medical and Surgical Sciences and Biotechnologies, Rome Sapienza University, Rome, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Casali
authors.affiliation: Human Motor Control Section, NINDS, Bethesda, MD, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Hallett
authors.affiliation: Department of Neurology, Yale School of Medicine, New Haven, CT, USA.
authors.forename: Elan D
authors.initials: ED
authors.lastname: Louis
authors.affiliation: FNRS ULB-Erasme, Unité d'Etude du Mouvement, 808 Route de Lennik, 1070, Brussels, Belgium. mmanto@ulb.ac.be.
authors.forename: Mario
authors.initials: M
authors.lastname: Manto
authors.affiliation: Clinical and Experimental Neurolinguistics, CLIN, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium.|Department of Neurology and Memory Clinic, ZNA Middelheim General Hospital, Antwerp, Belgium.
authors.forename: Peter
authors.initials: P
authors.lastname: Mariën
authors.affiliation: Helios Klinik Kipfenberg, Kindingerstrasse 13, D-85110, Kipfenberg, Germany.|Neurologische Universitätsklinik, Philipps-Universität Marburg, Baldingerstraße, D-35043, Marburg, Germany.
authors.forename: Dennis A
authors.initials: DA
authors.lastname: Nowak
authors.affiliation: Ataxia Unit, Cognitive Behavioural Neurology Unit, Laboratory for Neuroanatomy and Cerebellar Neurobiology, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA.
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: Schmahmann
authors.affiliation: Department of Medical and Surgical Sciences and Biotechnologies, Rome Sapienza University, Rome, Italy.|Rehabilitation Centre, Movement Analysis LAB, Policlinico Italia, Rome, Italy.
authors.forename: Mariano
authors.initials: M
authors.lastname: Serrao
authors.affiliation: Department of Neurology, University Clinic Essen, Hufelandstrasse 55, 45147, Essen, Germany.|Department of Neurology, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.
authors.forename: Katharina Marie
authors.initials: KM
authors.lastname: Steiner
authors.affiliation: University of Munich, Munich, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Strupp
authors.affiliation: CRNL INSERM U1028 CNRS UMR5292, Team ImpAct, Bron, F-69676, France.|Lyon I University, Lyon, F-69373, France.|Hospices Civils de Lyon, Neuro-Ophthalmology and Neurology D, Hôpital Neurologique Pierre Wertheimer, Bron, F-69677, France.
authors.forename: Caroline
authors.initials: C
authors.lastname: Tilikete
authors.affiliation: Department of Neurology, University Clinic Essen, Hufelandstrasse 55, 45147, Essen, Germany.|Department of Neurology, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.
authors.forename: Dagmar
authors.initials: D
authors.lastname: Timmann
authors.affiliation: Department of Neurology and Memory Clinic, ZNA Middelheim General Hospital, Antwerp, Belgium.
authors.forename: Kim
authors.initials: K
authors.lastname: van Dun
mesh_terms: D002526:Cerebellar Diseases / Q000175:diagnosis* / Q000503:physiopathology*; D002531:Cerebellum / Q000503:physiopathology; D006801:Humans
keywords: A- or Dysdiadochokinesia; Affect; Ataxia; Cerebellar syndrome; Cerebellum; Cognition; Dysarthria; Dysmetria; Eye movements; Functional topography; Hypotonia; Language; Loops; Speech; Tremor