Prevalence in patients with TBI
One study of 301 consecutive cases in a clinic setting reported a 5% prevalence. PBA occurred in patients with more severe head injury and coincided with other neurological features suggestive of pseudobulbar palsy.
Brain Injury Association of America (BIAA) indicates that approximately 80% of survey respondents experience symptoms of an additional neurologic condition called pseudobulbar affect (PBA). 
Results from a recent investigation estimates the prevelance of pseudobulbar affect associated with traumatic brain injury to exceed more than 55% of survivors