MAR 14, 2018 07:30 AM PDT

Keynote Presentation: Ataxia, Dysmetria of Thought, and the Cerebellar Cognitive Affective Syndrome

Presented At Neuroscience 2018
C.E. CREDITS: P.A.C.E. CE | Florida CE
  • Professor of Neurology, Harvard Medical School Founding Director, Ataxia Unit Cognitive Behavioral Neurology Unit Director, Massachusetts General Hospital
      Dr. Schmahmann is Professor of Neurology at Harvard Medical School, and a Neurologist at the Massachusetts General Hospital where he is the Founding Director (1994) of the Ataxia Unit, Director of the Laboratory for Neuroanatomy and Cerebellar Neurobiology, and a member of the Cognitive Behavioral Neurology Unit. His research and clinical practice focuses on the neurology and basic science of the ataxias and other cerebellar disorders, and he has pioneered the role of the cerebellum in cognition and emotion.

      Dr. Schmahmann graduated with distinction from the University of Cape Town, South Africa, completed residency in the Neurological Unit of Boston City Hospital, and postdoctoral fellowship in the Department of Anatomy and Neurobiology at Boston University School of Medicine. He is a Fellow of the American Academy of Neurology, the American Neurological Association, and the American Neuropsychiatric Association of which he is Immediate Past President. He is a member of the Medical and Scientific Research Advisory Board of the National Ataxia Foundation, the Cerebellar Research Consortium for the Study of Cerebellar Ataxias, and on the Executive of the Society for Research on the Cerebellum and Ataxias. He has authored over 200 papers, chapters and clinical contributions, and written or edited 6 books. His awards include the Norman Geschwind Prize from the American Academy of Neurology and the Society for Behavioral and Cognitive Neurology, the Distinguished Neurology Teacher Award of the American Neurological Association, the Special Prize for Sustained Excellent in Teaching from, Harvard Medical School, and many visiting professorships. He has been cited in The Best Doctors in America since 1996.


    The cerebellum is incorporated into the distributed neural circuits subserving motor control, cognitive processing and the modulation of emotion. This lecture provides an overview of anatomical studies in monkey and functional magnetic resonance imaging studies in humans demonstrating topographic arrangement in the cerebellum of motor and non-motor domains.  We consider motor impairments such as ataxia, dysmetria and dysarthria as resulting from lesions of the motor cerebellum predominantly in the anterior lobe, whereas executive, linguistic, spatial, and emotional impairments (the cerebellar cognitive affective syndrome, CCAS) arise following lesions of the cognitive cerebellum in the posterior lobe. Affective dysregulation occurs particularly when lesions involve the cerebellar vermis. These higher order impairments represent subcortical disconnection syndromes, manifestations of dysmetria of thought resulting from loss of the universal cerebellar transform, the unique computation that the cerebellum contributes to functionally specific subcircuits within distributed cortico-subcortical networks. Patient studies reveal that the affective component of the CCAS manifests as deficits in the domains of attentional control, emotional control, social skill set, autism spectrum disorders and psychosis spectrum disorders. This new appreciation of cerebellar circuits, functions, and deficits has relevance for understanding and treating adults and children with cerebellar disorders; investigating neuropsychiatric diseases including autism and schizophrenia; and for new therapeutic possibilities in neuropsychiatry. This is exemplified by preliminary  evidence that transcranial magnetic stimulation applied to the cerebellar vermis improves negative symptoms and enhances quality of life in patients with schizophrenia.

    Objective for this lecture are:

    • To define the essential elements of the distributed neural circuits linking cerebellum with association and paralimbic areas as well as sensorimotor regions of the cerebral cortex.
    • Describe the clinical features and broader relevance of the cerebellar cognitive affective syndrome and the neuropsychiatry of the cerebellum.
    • Explain how the dysmetria of thought theory and the concept of the universal cerebellar transform account for the cerebellar role in cognition and emotion, and the relevance this has for novel approaches to treatment of neuropsychiatric disorders.

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