Olfactory dysfunction, gambling task performance and intracranial lesions after traumatic brain injury

Area of Science:

• Neuroscience
• Neurology
• Rehabilitation Medicine

Background:

• Traumatic brain injury (TBI) can lead to persistent sensory and cognitive deficits.
• Olfactory dysfunction and impaired decision-making are common sequelae of TBI, but their relationship with injury severity and lesion characteristics requires further investigation.

Purpose of the Study:

• To determine the incidence of olfactory dysfunction in relation to TBI severity.
• To assess decision-making deficits and their association with intracranial lesion location and laterality post-TBI.

Main Methods:

• A 1-year prospective study of 115 participants (16-55 years) with mild, moderate, or severe TBI.
• Olfactory function was assessed using the Brief Smell Identification Test at 3 months and 1 year post-TBI.
• Decision-making was evaluated using the Iowa Gambling Task (IGT) and Delis-Kaplan Executive Function System tasks at 3 months, with MRI performed at 1 year.

Main Results:

• The incidence of olfactory dysfunction was 22.3% at 3 months and 13.5% at 1 year, with no significant differences across TBI severity groups.
• Anosmia occurred in 10% of severe TBI cases versus 3% of mild TBI cases.
• Decision-making was impaired in 83% of participants with intracranial lesions and 71% without, with no significant differences based on lesion characteristics or TBI severity.

Conclusions:

• Olfactory dysfunction after TBI is common but generally improves and is independent of injury severity, though anosmia correlates with severity.
• Significant decision-making deficits persist after TBI, irrespective of lesion location, laterality, or overall severity.
• These findings highlight the need for targeted interventions for persistent olfactory and decision-making impairments following TBI.