Cognitive disorders are difficulties with brain processing that cause problems with cognitive function and domains such as memory, language, problem solving, attention or processing speed. They remain frequently reported in people living with HIV, despite virological suppressive ART. The prevalence of cognitive impairment in people living with HIV is challenging to ascertain, given that several different diagnostic criteria have been utilised, with a reported range of between 5% and 50%. In addition, delirium is a common acute cognitive function disorder in hospitalised or critically ill people living with HIV and can also be a presenting symptom of undiagnosed acute HIV.
While the true prevalence may never accurately be known (and is liable to change as HIV management and treatment develops) a significant proportion of people living with HIV do experience cognitive disorders or neuropsychiatric side-effects to ART, and thus should be assessed and managed. Furthermore, cognitive symptoms may be misdiagnosed as mental health difficulties, or conversely mental health issues may be incorrectly attributed to cognitive health, and additionally substance use can cause short- and long-term cognitive effects. Therefore, questioning for mental health and substance use should always occur alongside questioning for cognitive disorders.
People living with HIV should be questioned for symptoms of concentration or memory difficulties, or alternatively many short/brief screening cognitive tests and batteries exist (Appendix 6). None of these replace a full neuropsychological assessment but may be useful in determining who should be referred for full assessment. Some screening tests are generalist and some in theory ‘HIV specific’; however, all have their limitations.
Should screening tests or clinical presentation indicate possible difficulties then a full neuropsychological assessment may be warranted, which will be conducted by a clinical psychologist. There are a variety of different neuropsychological assessment tests available, assessing different cognitive domains. As with screening tests there is no gold-standard test or tests, rather the selection of tests used will depend on different factors such as the approach used (e.g. hypothesis versus battery driven), as well as available norms, experience of the assessor, if re-testing is planned, and what tests are available locally.
Cognitive rehabilitation strategies or services should be offered as soon as HIV-associated cognitive impairment is detected (alongside mitigation of other cognitive risk factors and neurological review) and be based on a compensatory rather than restorative approach. If antiretroviral neurotoxicity is suspected as the cause of cognitive impairment, then the ARVs should be reviewed.