Pathological laughter and crying in patients with closed traumatic brain injury

We report on the clinical and radiological features in 16 adult patients who suffered a traumatic brain injury and subsequently developed pathological laughter and crying. Patients with pathological laughter and crying were identified from among 301 consecutive brain-injured admissions to a trauma centre and subsequently to a rehabilitation facility. Patients displaying pathological laughter and crying had a greater severity of injury than patients without the syndrome; they also had other associated neurological features compatible with pseudobulbar palsy. Pathological laughter alone, or combined with crying, was more frequent than crying alone. An attempt to correlate clinical features with focal lesions on neuroimaging studies yielded inconsistent results. The theoretical anatomical substrate for pathological laughter and crying in patients with traumatic brain injury is discussed.