TORONTO, CANADA -- It's a family's worst nightmare. A traumatic head injury leaves a relative in a confused state. The family desperately wants to know when the relative will recover and get their memory back.
Now a group of Toronto researchers say they have found a way to more accurately predict recovery of "continuous memory" -- that is, the perfect free recall of three learned words after 24 hours. It's a key indicator that the brain's cognitive function is working again.
The findings, published in the March 28th issue of the international journal Neurology, could lead to improvements in the care of patients who've had a serious head injury. Doctors would be able to determine with more accuracy when the patient is well enough cognitively to go home. This would lessen the risk of patients being prematurely discharged from hospital before their cognitive function has recovered.
Scientists from Baycrest's Rotman Research Institute, Sunnybrook and Women's College Health Sciences Centre, the University of Toronto, and St. Michael's Hospital, collaborated on the research. They found that starting the assessments as quickly as possible after injury AND using currently available predictive methods in combination with other factors, such as age and duration of loss of consciousness, can provide a more precise gauge of a patient's prospects for cognitive recovery.
"The results of our study provide clinicians with the appropriate measurement tools to make decisions about discharge," says Dr. Donald Stuss, Director of the Rotman Research Institute at Baycrest Centre for Geriatric Care, and lead author in the study. "A more accurate gauge of a patient's mental status will also guide families in taking care of their loved ones."
Conducted during the years 1992 to 1995, the study assessed recovery of continuous memory in 94 patients who were admitted to hospital with a non-penetrating traumatic brain injury. The injury was categorized as either mild, moderate or severe. Patients ranged in age from 16 to 65, were English speaking and literate, and responsive within one month of injury.
Memory and attention tests were administered to each subject as soon as possible after admission. Predictive measurements used regression models to look at duration of unconsciousness. A longer unconscious period generally means a longer delay in recovering word recall.
The Toronto researchers looked at other factors that may influence recovery of continuous memory, including capacity (years of education and age), and compromise (degree of impairment in general functional brain state). Combining these factors with the regression models, they were able to create a more sensitive predictive index for a patient's recovery of continuous memory.
The publication of these findings in Neurology is the third part in a trilogy of notable strides made by this team of researchers in predicting recovery from traumatic brain injury.
- In 1998, the group proved that a simple "three-word recall" test is a more reliable measure of emergence from post-traumatic amnesia than the conventional Galveston Orientation and Amnesia Test (Canadian Journal of Neurology, Vol. 25, No. 2, May 1998).
- In 1999, the group challenged the accuracy of the clinical term "post-traumatic amnesia", which describes the period of acute recovery after traumatic brain injury. The researchers argued that attentional problems (learning and retaining new information) are more prominent in the acute recovery period than amnesia. They proposed that a more appropriate characterization of this recovery period is "post-traumatic confusional state" (Journal of Neurosurgery, Vol. 90, April 1999).
Funding for the study was provided by the Ontario Mental Health Foundation and the Medical Research Council of Canada. The research team included scientists from the Rotman Research Institute at Baycrest Centre for Geriatric Care; the University of Toronto's departments of Medicine (Neurology, Rehabilitation Science), Surgery (Neurosurgery) and Psychology; Sunnybrook and Women's College Health Sciences Centre; and St. Michael's Hospital.
Journal
Neurology