Neurological problems related to head injuries were generally linked to a single traumatic brain injury (TBI). In a new study, scientists have linked depression and cognitive functioning problems as a result of repetitive head impacts (RHI).
A large collaborative study by Boston University (BU) Alzheimer's Disease and Chronic Traumatic Encephalopathy (CTE) Centers, the University of California, San Francisco (UCSF), and San Francisco VA Healthcare System included the records of 13,323 people aged 40 and above from the Brain Health Registry. 725 (5%) of the participants had a history of repetitive head impacts through contact sports, abuse, or military service while 7,277 had TBI.
The scientists also compared the effects of a TBI after the loss of consciousness (LOC) versus being conscious.The participants took the Ohio State University TBI Identification Method; the Geriatric Depression Scale (GDS-15); and the CogState Brief Battery and Lumos Labs NeuroCognitive Performance Tests. The overall results showed that individuals with RHI had the strongest developments of depression compared to those with TBI.
Traumatic Brain Injury Versus Repetitive Head Impacts
'The findings underscore that repetitive hits to the head, such as those from contact sport participation or physical abuse, might be associated with later-life symptoms of depression. It should be made clear that this association is likely to be dependent on the dose or duration of repetitive head impacts and this information was not available for this study,' said Dr. Michael Alosco from the BU School of Medicine (BUSM) and co-director of the BU Alzheimer's Disease Center Clinical Core.
The worst combination leading to depressive symptoms and cognition problems were those who had a history of repetitive head injury, TBI, and loss of consciousness from contact sports and abuse. The neurocognitive tests assessed their memory, learning, processing speed, and reaction time, comparing their results to participants without head trauma.
The same group that had the most depressive symptoms also had the worst performance in these tests. Dr. Robert Stern from the BUSM and the BU CTE Center said that not everyone with RHI 'will develop later-life problems with cognitive functioning and depression. However, results from this study provide further evidence that exposure to repetitive head impacts, such as through the routine play of tackle football, plays an important role in the development in these later-life cognitive and emotional problems'
Researchers from Boston University conducted an earlier study with football players developing the brain disease chronic traumatic encephalopathy (CTE). Years of playing the sport resulted in a 30% chance of developing CTE and 17% increased odds of developing severe CTE, which could result in personality changes, aggression, depression, and dementia.
The team hopes to expand their research with data from the Brain Health Registry. Dr. Michael Weiner said, 'the Brain Health Registry is a novel and exciting resource for both the scientific community and the general public. It allows for large-scale recruitment, screening, and study of dementia, and more than 60,000 individuals across the world are enrolled.' People can track various neurological aspects such as memory and behavior over time while data can be used for research and developing treatment.