For some patients with mild traumatic brain injury (MTBI), or concussion, the abnormal distribution of white brain matter closely resembles the early stages of Alzheimer’s, according to a new study published in the journal Radiology.
“Findings of MTBI bear a striking resemblance to those seen in early Alzheimer’s dementia,” said the study’s lead author, Saeed Fakhran, M.D., assistant professor of radiology in the Division of Neuroradiology at the University of Pittsburgh School of Medicine. “Additional research may help further elucidate a link between these two disease processes.”
Despite the name, MTBI is by no means mild — approximately 15 percent of these patients suffer with long term neurological symptoms.
“Sleep-wake disturbances are among the earliest findings of Alzheimer’s patients, and are also seen in a subset of MTBI patients,” Fakhran said. “Furthermore, after concussion, many patients have difficulty filtering out white noise and concentrating on the important sounds, making it hard for them to understand the world around them.”
“Hearing problems are not only an independent risk factor for developing Alzheimer’s disease, but the same type of hearing problem seen in MTBI patients has been found to predict which patients with memory problems will go on to develop Alzheimer’s disease.”
For the study, researchers set out to determine if there was a link between white matter patterns after injury and the severity of post-concussion symptoms in MTBI patients with normal findings on conventional MRI exams.
The researchers studied brain images performed on 64 MTBI patients and 15 control patients, using an advanced MRI technique called diffusion tensor imaging, which locates microscopic changes in the brain’s white matter.
Of the MTBI patients, 42 (65.6 percent) were men, and the mean age was 17. Sports injury was the reason for concussion in two-thirds of the patients. Sleep-wake disturbances were among the most disabling symptoms, directly reducing quality of life and productivity and increasing memory and social dysfunction.
“When we sleep, the brain organizes our experiences into memories, storing them so that we can later find them,” Fakhran said. “The parahippocampus is important for this process, and involvement of the parahippocampus may, in part, explain the memory problems that occur in many patients after concussion.”
According to Fakhran, the results suggest that the true problem facing concussion patients may not be the injury itself, but rather the brain’s response to that injury.
“Traditionally, it has been believed that patients with MTBI have symptoms because of abnormalities secondary to direct injury,” he said. “Simply put, they hit their head, damaged their brain at the point of trauma and thus have symptoms from that direct damage.”
“Our preliminary findings suggest that the initial traumatic event that caused the concussion acts as a trigger for a sequence of degenerative changes in the brain that results in patient symptoms and that may be potentially prevented. Furthermore, these neurodegenerative changes are very similar to those seen in early Alzheimer’s dementia.”
The researchers hope these findings will lead to better treatments.
“The first step in developing a treatment for any disease is understanding what causes it,” said Fakhran. “If we can prove a link, or even a common pathway, between MTBI and Alzheimer’s, this could potentially lead to treatment strategies that would be potentially efficacious in treating both diseases.”