Relationship between severity of traumatic brain injury (TBI) and extent of auditory dysfunction

Objective: To find out the relationship between severity of traumatic brain injury (TBI) and extent of auditory dysfunction Background: Most of the studies have taken the subjects with TBI as one group without taking into account the extent of head injury viz, mild, moderate and severe. Combining all the three groups has resulted in presenting an incomplete picture of auditory deficits following TBI. Methods and procedures: The sample population consisted of 290 subjects with TBI (study group) and 50 otologically normal subjects as controls. The subjects in the study group were further sub-divided into mild (n = 150), moderate (n = 100) and severe (n = 40) TBI. The audiological assessment consisted of pure tone audiometry, speech audiometry, tympanometry, acoustic reflex testing, auditory brainstem response and middle latency response audiometry. Results and conclusions: An association was observed between the extent of auditory dysfunction and severity of TBI. This association was more pronounced for hearing status at high frequencies and ABR/MLR components. ABR Wave V absolute latency and I-V interpeak latency increased with severity of TBI. Amplitude of MLR wave Na and Pa decreased with increasing severity. It is suggested that subjects should be evaluated for hearing difficulties based on their severity of TBI.