title: Impaired corticopontocerebellar tracts underlie pseudobulbar affect in motor neuron disorders.
abstract: OBJECTIVE
  The objectives of the study were (1) to determine the prevalence and characteristics of pseudobulbar affect (PBA) in patients with primary lateral sclerosis (PLS) and amyotrophic lateral sclerosis (ALS) in an outpatient clinic population, and (2) to test the hypothesis that damage of inputs to the cerebellum, leading to cerebellar dysmodulation, is associated with PBA.
  
  
  METHODS
  Chart review of all patients with PLS and ALS seen between 2000 and 2013. The examining neurologist documented the presence or absence of PBA in 87 patients. Forty-seven patients also had diffusion tensor imaging (DTI) studies. Tract-based spatial statistics were used to compare DTI of patients with and without PBA to identify altered white matter tracts associated with PBA.
  
  
  RESULTS
  Thirty-one of 50 patients with PLS and 12 of 37 patients with ALS had PBA. Psychiatric/emotional assessment found congruence between mood and affect during episodes, but excessive magnitude of the response. DTI studies of 25 PLS and 22 ALS patient brains showed reduced fractional anisotropy of the corticospinal and callosal white matter tracts in all patients. Patients with PBA additionally had increased mean diffusivity of white matter tracts underlying the frontotemporal cortex, the transverse pontine fibers, and the middle cerebellar peduncle.
  
  
  CONCLUSIONS
  PBA is common in PLS. Imaging findings showing disruption of corticopontocerebellar pathways support the hypothesis that PBA can be viewed as a "dysmetria" of emotional expression resulting from cerebellar dysmodulation.
authors.affiliation: From the National Institute of Neurological Disorders and Stroke (M.K.F., R.K., M.P.K., O.S., M.S., L.D., T.W., A.M.), NIH, Bethesda, MD; and Departments of Psychiatry and Neurology (E.D.H.), Columbia University, New York, NY. floeterm@ninds.nih.gov.
authors.forename: Mary Kay
authors.initials: MK
authors.lastname: Floeter
authors.affiliation: From the National Institute of Neurological Disorders and Stroke (M.K.F., R.K., M.P.K., O.S., M.S., L.D., T.W., A.M.), NIH, Bethesda, MD; and Departments of Psychiatry and Neurology (E.D.H.), Columbia University, New York, NY.
authors.forename: Rohan
authors.initials: R
authors.lastname: Katipally
authors.affiliation: From the National Institute of Neurological Disorders and Stroke (M.K.F., R.K., M.P.K., O.S., M.S., L.D., T.W., A.M.), NIH, Bethesda, MD; and Departments of Psychiatry and Neurology (E.D.H.), Columbia University, New York, NY.
authors.forename: Meredith P
authors.initials: MP
authors.lastname: Kim
authors.affiliation: From the National Institute of Neurological Disorders and Stroke (M.K.F., R.K., M.P.K., O.S., M.S., L.D., T.W., A.M.), NIH, Bethesda, MD; and Departments of Psychiatry and Neurology (E.D.H.), Columbia University, New York, NY.
authors.forename: Olivia
authors.initials: O
authors.lastname: Schanz
authors.affiliation: From the National Institute of Neurological Disorders and Stroke (M.K.F., R.K., M.P.K., O.S., M.S., L.D., T.W., A.M.), NIH, Bethesda, MD; and Departments of Psychiatry and Neurology (E.D.H.), Columbia University, New York, NY.
authors.forename: Matthew
authors.initials: M
authors.lastname: Stephen
authors.affiliation: From the National Institute of Neurological Disorders and Stroke (M.K.F., R.K., M.P.K., O.S., M.S., L.D., T.W., A.M.), NIH, Bethesda, MD; and Departments of Psychiatry and Neurology (E.D.H.), Columbia University, New York, NY.
authors.forename: Laura
authors.initials: L
authors.lastname: Danielian
authors.affiliation: From the National Institute of Neurological Disorders and Stroke (M.K.F., R.K., M.P.K., O.S., M.S., L.D., T.W., A.M.), NIH, Bethesda, MD; and Departments of Psychiatry and Neurology (E.D.H.), Columbia University, New York, NY.
authors.forename: Tianxia
authors.initials: T
authors.lastname: Wu
authors.affiliation: From the National Institute of Neurological Disorders and Stroke (M.K.F., R.K., M.P.K., O.S., M.S., L.D., T.W., A.M.), NIH, Bethesda, MD; and Departments of Psychiatry and Neurology (E.D.H.), Columbia University, New York, NY.
authors.forename: Edward D
authors.initials: ED
authors.lastname: Huey
authors.affiliation: From the National Institute of Neurological Disorders and Stroke (M.K.F., R.K., M.P.K., O.S., M.S., L.D., T.W., A.M.), NIH, Bethesda, MD; and Departments of Psychiatry and Neurology (E.D.H.), Columbia University, New York, NY.
authors.forename: Avner
authors.initials: A
authors.lastname: Meoded
mesh_terms: D000690:Amyotrophic Lateral Sclerosis / Q000473:pathology* / Q000523:psychology; D016880:Anisotropy; D002531:Cerebellum / Q000473:pathology; D002540:Cerebral Cortex / Q000473:pathology; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019964:Mood Disorders / Q000453:epidemiology* / Q000473:pathology*; D016472:Motor Neuron Disease / Q000473:pathology* / Q000523:psychology; D009413:Nerve Fibers, Myelinated / Q000473:pathology; D009434:Neural Pathways / Q000473:pathology; D011149:Pons / Q000473:pathology; D015995:Prevalence; D011712:Pyramidal Tracts / Q000473:pathology; D012189:Retrospective Studies