The neuroscience of HIV

Posted on Thursday, December 1, 2016
Dr. Lesley Fellows a neurologist specializing in disorders of cognition and one of the principal investigators of the Positive Brain Health Now study.

Neurologist Dr. Lesley Fellows is one of the principal investigators of the Positive Brain Health Now study.

By Neale McDevitt

December 1 is World AIDS Day, and the consequences of testing positive for HIV have changed dramatically over the past 30 years. HIV/AIDS has evolved from a death sentence to a chronic condition that can be managed by medication.

This change has brought about a new set of concerns for people living with HIV/AIDS, including brain function. As their life expectancies increase, it is becoming clear that both cognition and mental health can be affected by HIV, even with excellent medical support. 

Researchers at the Montreal Neurological Institute and Hospital and the McGill University Health Centre, together with investigators at other universities and clinics across Canada and in Australia, are conducting a major study, called Positive Brain Health Now, to better understand the effects of HIV infection on brain health. In all, 850 people living with HIV have volunteered for the study, and are undergoing regular cognitive testing over three years, along with detailed assessments of their general health, mood, day-to-day function and quality of life. This is among the largest cohorts focusing on brain health in people with HIV.

The project’s lead investigators are McGill’s Dr. Lesley Fellows, a neurologist specializing in disorders of cognition, and Dr. Marie-Josée Brouillette, a psychiatrist whose primary area of interest is the psychiatric care of patients, more specifically those infected with HIV. They work with a team of 28 co-investigators in Australia and across Canada.

Recently, the McGill Reporter spoke with Dr. Fellows about Positive Brain Health Now, it’s multifaceted approach and what she hopes it will accomplish. 

People don’t often think about neurological issues when they think about HIV or AIDS. What is the association? 

In the early days of the epidemic, dementia was common in people with HIV/AIDS. It was a late development that usually portended death over the course of a few months. Understandably, people still worry about that today.

Now we’re seeing very little dementia or severe cognitive trouble. More often it is mild forgetfulness, sometimes so mild that it can be hard to distinguish from the normal changes that anyone would experience as they grow older.

Tell us about the Positive Brain Health Now study. 

The project has two goals.

First, we want to get a better understanding of cognitive function in people living with HIV and how it evolves over time. Does it worsen? Is it stable? Not much is known on the subject.

At the same time, we want to do something more than just characterize and observe people. We want to offer them some sort of treatment. It is important to help patients, as well as researchers, understand how modifiable these cognitive issues may be. The best way to do that is to offer treatment and see if we can improve their situation.

Is this a shift in focus in HIV research?

In some ways, yes. The development of effective anti-retroviral treatment means that HIV can be controlled to the point where most patients can live normal lifespans.

Now, with HIV under control, it is time to refocus on quality of life. As these people are getting older, we are interested in the interaction between aging, the effects of the infection itself, and the other conditions that go along with having a chronic disease, HIV in particular.

Will you be assessing only cognitive function? 

No. We are also looking at mental health and general health (including how well controlled the HIV infection is; and the presence of other conditions, such as cardiovascular disease).

We think this problem is multifactorial, so we’re trying to understand all those factors and figure out which ones are the most important.

How do you know which memory issues are HIV-related and which are just part of the aging process?

It’s clinically challenging to try and sort out. At the very earliest stages, trying to distinguish between what’s a sign of something serious, whether early Alzheimer’s or HIV-related brain injury, and what is in the range of normal cognitive function as a person is getting older has always been a challenge in general for researchers.

Is there a difference, then, between people with HIV who complain of memory problems and people who are HIV negative with the same memory concerns? 

One of the main differences is that people living with HIV often face these memory issues at a much younger age than a typical Alzheimer’s patient. So the traditional tools that people would use in the clinic – the simple bedside memory tests, for example. – are too easy for these younger, more functional people.

We hope to develop better ways of assessing cognition that can be used in frontline HIV clinics by physicians who aren’t neurologists or neuropsychologists. We’re trying to equip them with simple tools that are, nonetheless, sensitive and appropriate to assess HIV patients who present with very mild symptoms.

So you’re also hoping to revamp screening and testing?

Exactly. For example, when you say someone is impaired, you are comparing them to another group. But sometimes those comparisons are not really appropriate.

In North America, many people with HIV may be immigrants who may be speaking a third language when they do the testing. This can lead to poor performance that has nothing to do with their cognitive ability.

How do you rectify that? 

We think the best way is to observe how people change over time, not comparing them against ‘normal.’ If there is a noticeable decline, you have to intervene. But to do that usefully you have to have ways of measuring cognitive function that are sensitive enough that they can be used repeatedly.

This longitudinal study will help in that regard?

Hopefully this will let us reliably determine whether there are different patterns. Do people improve, stay stable or worsen? Of course we’re especially interested in people who worsen. Can we establish why? Can we show what are the causes?

Then in our interventions we can try and change one or another aspect of the person’s situation and see if we can actually improve their memory.

What kind of interventions?

We will try interventions that are not medication-based – things like exercise; computerized cognitive training; and more traditional, group-based cognitive rehabilitation. Interventions to help them with their sleep, to help them with their mood, and so on.

At the end of this study we will have real information that patients can use right away to make decisions to improve their lives or that can be used in clinics to help clinicians provide better care for patients.

 Learn more about the Positive Brain Health Now study

Dr. Lesley Fellows discusses the Positive Brain Health Now project

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