It is believed that up to 20% of structural epilepsy in the general population is a result of TBI (Bushnik et al. 2012). Of all patients with TBI who are hospitalized, 5% to 7% will experience PTS. However, the incidence of PTS is much higher on rehabilitation units (as high as 18%), which reflects increased injury severity and the presence of a higher number of risk factors in this population (Armstrong et al. 1990; Bontke et al. 1993; Cohen & Groswasser 1991; Kalisky et al. 1985; Sazbon & Groswasser 1990; Sundararajan et al. 2015; Wang et al. 2013a). The incidence of late post-traumatic seizures (LPTS) ranges from 5% to 19% for the general population (Bushnik et al. 2012). Zhao and colleagues (2012) found that when seizures occurred post-TBI, 0.4% were immediate, 0.5% were early, and 88.7% were late. A study examining 236,164 individuals with TBI found that 2.4% had pre-existing epilepsy or a seizure disorder (Wilson & Selassie 2014); unfortunately, the consequences of a TBI may be more severe in this population.
For those who sustain a severe non-penetrating TBI, approximately 11% will experience LPTS and for those who have a TBI as the result of a penetrating injury, the incidence increases to 13% to 50% (Ascroft 1941; Caveness & Liss 1961; Malav et al. 2015; Yablon 1993). In young adults TBI is the leading cause of epilepsy (Annegers 1996). Following acquired brain injury (ABI), seizures have been associated with secondary accidental injury, depression, a loss of independence (i.e., driving privileges) and a reduction in employability (Andelic et al. 2009; Brain Injury Special Interest Group 1998).