The incidence of severe forms of HIV-associated neuorcognitive disorders, or HAND, has declined significantly with the availability of combination antiretroviral drug therapy over the last 20 years.
But the prevalence of the milder form has remained stable and even slightly increased, affecting 50 to 60 per cent of people living with HIV and AIDS.
"Screening tools have not been updated to reflect this change," said Dr. Sean B. Rourke, a neuropsychologist who heads the Neurobehavioural Research Unit at St. Michael's. "We are still trying to use or adapt the older dementia screening tools to catch the milder form of HAND."
Dr. Rourke said that having effective screening tests to identify and differentiate the two different forms of HAND is important for treatment decision-making. The current standards of practice requires a detailed neuropsychological examination, which is time-consuming and not readily accessible.
"Identifying that patients have a mild form of this condition is critical," said Dr. Rourke. "Even mild neurocognitive problems can have a significant impact on a person's everyday functioning, affecting his or her ability to take medications or ability to perform at work, and may also lead to more social isolation and withdrawal."
In a review of literature published today in the journal AIDS
, Dr. Rourke and colleagues looked at 31 previously published studies to see the rate at which commonly used tools in practice were detecting milder forms of HAND.
They found that the two most frequently used tests - the HIV Dementia Scale and the International HIV Dementia Scale - were effective in identifying severe forms of neurocognitive impairment such as dementia, but ineffective for more mild form of HAND. None of the tools studied identified mild HAND conditions well enough to be recommended for broader use.
"With the prevalence of milder forms of HAND increasing, and limited resources available for formal neuropsychological examinations, there is a critical need to be able to screen and identify people with HAND," Dr. Rourke said. "Improved screening tools could go a long way in improving the care, quality of life, and study of treatment interventions of individuals living with HIV and AIDS."
Dr. Rourke said tools should be brief enough to be used in a clinic or health centre setting, and able to be administered by a trained individual with minimal equipment.
Dr. Rourke has received funding from the Canadian Institutes for Health Research to conduct the largest and methodologically rigorous study to date that will further examine existing screening tools for HAND to see if there are any modifications that can be made to make them more effective. He will also be testing new tools being developed by his colleagues in the United States, which show promise for being more effective with the milder forms of HAND. Final results from this study should be available in 2014.