title: Pathological laughter and crying: A case series and proposal for a new classification.
abstract: BACKGROUND
  Disorders of laughter and crying (DLC) are seen in several neuropsychiatric conditions. Their nomenclature remains under debate.
  
  
  METHODS
  We present the clinical and imaging findings of 17 patients with DLC and introduce a new classification based on phenomenology and pathogenesis. According to intensity and frequency of laughter and crying (observed behavioral output), patients were divided into hypoactive or hyperactive DLC and subdivided into 5 subtypes: sensory (positive and negative), motor (positive and negative), and mixed. The sensory subtype is represented by disorders of "feeling processing," whereas the motor subtype is represented by disorders of "emotion processing." "Positive" and "negative" describe elicitation by irritative vs destructive lesions, respectively.
  
  
  RESULTS
  Among the patients studied, DLC resulted from ischemic stroke (n = 12), intracerebral hemorrhage (n = 2), gunshot wound (n = 1), amyotrophic lateral sclerosis (n = 1), or vestibular migraine (n = 1). Ten patients had lesions in the brainstem, 4 in the cerebral hemispheres, and 2 in sub-cortical-diencephalic structures. Six patients had negative motor DLC, 5 had positive sensory DLC, 4 had negative sensory DLC, and 2 had positive motor DLC. Phenomenology changed or progressed to mixed DLC in 7 patients.
  
  
  CONCLUSIONS
  This novel phenomenological and pathomechanistic nomenclature explains all subtypes of DLC in neurologic, medical, and psychiatric conditions. Future studies are needed to validate it prospectively.
authors: Department of Neurology,Saint Louis University School of Medicine, St. Louis, MO, USA, Departamento de Clínica Médica, Universidade Federal do Ceará,Fortaleza, Brazil E-mail: gondimfranc@gmail.com.
authors: Francisco de Assis Aquino
authors: Fde A
authors: Gondim
authors: Florian P
authors: FP
authors: Thomas
authors: Salvador
authors: S
authors: Cruz-Flores
authors: Henry A
authors: HA
authors: Nasrallah
authors: John B
authors: JB
authors: Selhorst
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001526:Behavioral Symptoms / Q000145:classification* / Q000175:diagnosis / Q000209:etiology; D003448:Crying / Q000502:physiology*; D005260:Female; D006801:Humans; D007845:Laughter / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009422:Nervous System Diseases / Q000150:complications*; D055815:Young Adult