A study published in the Archives of Clinical Neuropsychology (February, 2001) found that seatbelt use in motor vehicle collisions was associated with the location of brain lesions in moderate to severe brain injury. Statistical analysis determined that both LOC and GCS scores were similar between restrained and unrestrained drivers. What was different, however, was the incidence and location of the brain lesions sustained by both groups. The unrestrained occupants were found to more likely sustain damage in the posterior and occipital regions of the brain while restrained occupants were more likely to sustain damage in the subcortical regions of the brain. Both groups were equally likely to sustain frontal lobe, temporal lobe, and brain stem lesions. Furthermore, for patients having sustained moderate to severe brain injury, it made no difference whether they were or were not wearing seat belts at the time of their injury!
These findings suggest that seatbelts alter the body’s response to the forces inherent in motor vehicle collisions. Restrained occupants were considered to be less likely to experience posterior and occipital contact to the skull.
Reasons the restrained occupants sustained a higher frequency of subcortical lesions involving the basal ganglia, hypothalamus, thalamus, corpus collosum, and the internal capsule were suspected to be due to the greater degree of inertial forces focused in the head and neck while the torso retained a disproportionately greater level of restraint. Consistent with previous research, the frontal and temporal lobes of the brain are particularly susceptible to damage during acceleration/deceleration accidents, regardless of how the head is struck. Neuropsychological testing, however, revealed that unrestrained individuals were found to have greater impairment in frontal lobe functioning. Another finding noted in this study was that seatbelt use did appear to be effective in reducing the incidence of mild TBI, although the inertial forces effect would be anticipated to remain an influential factor in such cases.