Traumatic brain injury assessed with olfactory event-related brain potentials

Area of Science:

• Neuroscience
• Ophthalmology
• Traumatology

Background:

• Traumatic brain injury (TBI) frequently results in olfactory dysfunction, impacting both sensory perception and cognitive processing.
• Current methods for assessing olfactory loss post-TBI lack objectivity and quantitative precision.
• Olfactory event-related potentials (OERPs) present a potential objective biomarker for olfactory function.

Purpose of the Study:

• To establish olfactory event-related potentials (OERPs) as an objective and quantitative tool for assessing sensory and cognitive olfactory dysfunction following TBI.
• To correlate OERP findings with clinical olfactory assessments and cognitive test performance in TBI patients.

Main Methods:

• OERPs were recorded from 25 TBI patients and 25 healthy controls using amyl acetate stimuli.
• TBI patients were categorized into anosmic, hyposmic, and normosmic groups based on smell function.
• Cognitive function was assessed using the Trail Making Test; trigeminal nerve function was confirmed with ammonia OERPs in anosmic patients.

Main Results:

• Anosmic TBI patients showed absent N1, P2, and P3 OERP amplitudes, while hyposmic and normosmic TBI patients exhibited reduced amplitudes compared to controls.
• Trigeminal OERPs in anosmic TBI patients were normal, confirming the olfactory specificity of the deficits.
• A significant correlation was observed between OERP abnormalities and cognitive deficits measured by the Trail Making Test.

Conclusions:

• Olfactory event-related potentials (OERPs) serve as a reliable objective measure for quantifying sensory and cognitive olfactory loss after TBI.
• OERPs demonstrate the dual nature of olfactory impairment in TBI, affecting both smell perception and cognitive processing.
• This study supports the clinical utility of OERPs for the diagnosis and management of olfactory dysfunction in TBI survivors.