Social disinhibition: Piloting a new clinical measure in traumatic brain injury (TBI) individuals

Background and aims: Deficits in social disinhibition (i.e., a failure to inhibit automatic responses in favour of producing more socially acceptable responses) are common to many neurological conditions involving frontal lobe dysfunction (e.g., TBI). Measures of inhibitory or interference control (e.g., Haylings Sentence Completion test) are often used in clinical practice to infer behaviour and emotion regulation difficulties in TBI populations. However, these tests may not be measuring the same type of disinhibition that might occur in social contexts. This study has two aims: (1) to examine whether individuals with TBI are impaired in inhibiting automatic verbal responses to complex social information and whether they are impaired in their ability to produce more socially acceptable positive responses; and (2) to develop a new “Social Disinhibition Task” that is able to detect social disinhibition deficits in clinical (as opposed to laboratory) settings.

Method: Participants (19 moderate-to-severe TBI and 14 healthy controls) viewed scenes of complex social situations, and were asked to describe a character in them (Part A), describe a character while inhibiting inappropriate or negative responses (Part B), and describe a character while not only inhibiting negative responses, but also providing positive utterances (Part C).

Results: While TBI individuals and healthy control participants responded similarly to Part A, TBI individuals were significantly impaired on Part B indicating that they experienced difficulties in inhibiting automatic responding. There was a trend towards impairment on Part C in TBI individuals, indicating possible difficulties with the ability to produce positive and more socially acceptable responses.

Conclusions: This pilot study makes an important contribution toward meeting the need for a well-validated clinical assessment tool that is capable of assessing social disinhibition deficits in those with frontal lobe dysfunction.