Nov

The effects of HAND* on truck drivers and driving

2013-11-28 09:12
Blood vials

On 26 March 2013 Sisa Nonama was sentenced to nine years imprisonment, with three years suspended for five years. He was the driver of the passenger bus that crashed in the Hex River Pass in 2010, leaving 23 people dead.

It was reported that he was travelling 20km/h over the legal speed limit, that the bus was in sixth gear when it should have been in first, and that he did not have the required license to operate the vehicle. A radio news report mentioned that, at sentencing, the magistrate took into account that Mr Nonama is HIV-positive, suffering from tuberculosis and renal failure. The report that Mr Nonama is HIV+ suggests that his story may be more complicated than it appears. If Mr Nonama was HIV+ at the time of the accident, there is a roughly 50% chance that he may have been suffering HIV-Associated Neurocognitive Disorders (HAND).

The HI-Virus can affect any organ in the body, including the brain. The virus enters the brain through the blood-brain barrier (BBB), the membrane that usually protects the brain from viruses and other bad elements. Although there is medication that offers some protection against this, the currently available antiretroviral (ARV) treatments are less successful at crossing the BBB than the HI-Virus itself, essentially creating a reservoir for the virus in the central nervous system. This may lead to approximately 50% of people living with HIV/AIDS developing the cognitive disorders collectively known as HAND.

A study conducted by the Groote Schuur Hospital-HIV Mental Health Group in the Western Cape in 2011 found that in a community sample, 25% of people living with HIV/AIDS with a CD4 count lower than 200 met the criteria for HIV-Associated Dementia (HAD), 42% for Minor Neurocognitive Disorder (MND) and 9% for Asymptomatic Neurocognitive Impairment (ANI). Twenty-four percent were neurocognitive normal.

What is HIV-Associated Neurocognitive Disorders (HAND)?

HAND is the term that describes a range of cognitive impairments that some people living with HIV/AIDS may suffer from. It affects multiple functions, including neuropsychological ability , that is, the way people think: decision-making, multi-tasking, attention and memory. It also affects the way people behave, for example mood swings, irritability and apathy, and the ability to function on a daily basis, for example being able to take care of oneself or do your job. Still further, it affects motor movement, the ability to use your fingers, hands and/or limbs. Importantly, people with HAND tend to be less adherent to their medication.

HAND is divided into three categories, Asymptomatic Neurocognitive Impairment (ANI), the mildest impairment, followed by Minor Neurocognitive Disorder (MND), and HIV-Associated Dementia (HAD). A new category, ‘˜In Remission’, has recently been added because there is good evidence that people who have been diagnosed with HAND can improve. and Opportunistic Infections 2012.

David A. Wohl, (2012). The University of North Carolina. NeuroAIDS at Conference on Retroviruses

The person with HAND may be the first to notice that they are not performing at the same level that they usually perform at, but this is only if they have insight into their condition. They themselves or colleagues may notice that they have some or all of the following symptoms , more and more difficulty following instructions, poorer memory than before, clumsiness, attention keeps drifting, thinking is slower than usual, and moving slower than before. This may also be accompanied by depression and/or anxiety. These, along with other cognitive and bahavioural symptoms increase with the severity of the disorder.

Any of the above-mentioned symptoms can affect driving, but particular concerns are slower reaction times, poorer multi-tasking and decision making skills, and attention deficits. Even though much of driving is over-learnt behaviour (and becomes second nature), the habitual nature of driving becomes less relevant when drivers are faced with emergency situations, as in the case of the Hex River Pass accident.

It is possible that Mr Nonama had experienced memory and concentration difficulties for some time but had not reported it. There may even have been prior minor incidents, like scraping the bus in the parking lot as he started to misjudge distances. And, ultimately, his judgement may have failed as his ability to scan his environment and integrate the information while driving was badly affected. This, off course, is conjecture, but the scenario is not implausible, and not one that only applies to Mr Nonama.

Although HAND occurs more commonly in people with lower CD4 counts (the predictor of immune health), it is seen in people with both high and low CD4 counts. So, while the CD4 count is the biological marker that is used to decide when a person living with HIV/AIDS should be initiated on ARV treatment, there is no correlation between CD4 count and HAND. This means that CD4 count is not a good indicator of whether a person may have or develop HAND. HAND can only be diagnosed by a neuropsychologist doing a thorough neuropsychological assessment, while people can be screened for HAND by other health carers.

Why we should be concerned about HAND

Neuropsychological performance predicts mortality, which means that HAND is associated with earlier death. It is also associated with a worse quality of life. Everyday functioning (for example, medication management, financial management, grocery shopping and vocational functioning) is significantly worse in those with neuropsychological impairment. When comparing HIV+ individuals with neuropsychological impairment to HIV+ individuals without neuropsychological impairment, research indicates that 30% of the impaired group have difficulty in performing their jobs compared to only 6% of the non-impaired. Similarly there is a 22% vs. 10% unemployment rate, and a 28% vs. 6% greater likelihood of complaints of decreased work ability.

Driving

Taking the above into consideration, it is not surprising that there is evidence for a subset of HIV-infected individuals with cognitive impairment presenting with an overall decline in driving ability.

Research into the effects of HIV on driving started in the late 1990s. Space constraints prevent me from discussing the research in depth, but it is worth highlighting some important findings.

The HIV Neurobehavioral Research Centre (HNRC) in San Diego (USA) found, in a survey done with HIV+ drivers, that 29% reported a decline in their driving ability since they acquired the virus, with a significant number of cognitively impaired drivers being much less likely to be driving.

In another study, 33% of HIV+ neuropsychologically-impaired drivers compared to 10% of neuropsychologically-normal HIV+ drivers had moving violations in the previous year, with a trend of 33% vs. 18% toward a higher crash rate in the impaired group.

Following this, computer based driving simulations were used to test, among other tasks, lane tracking and city driving. Cognitively impaired individuals were five times more likely to fail the lane tracking task and had a significantly higher number of crashes on city driving than those who were not impaired. This research was then followed by on-road driving tests which classified HIV+ drivers with cognitive impairment as unsafe at a rate of 36%, compared to 6% in HIV+ but cognitively-normal drivers. In addition, the impaired group made almost three times as many navigational errors.

Other than the elevated level of risk in driving for HIV+ cognitively-impaired drivers, this research shows that being HIV+ alone does not increase the risk of driving, but that the cognitive changes that might accompany HIV is the risk factor. There is no question that HAND has a significant impact on driving skills and that it therefore cannot be ignored in the management of drivers.

Wellbeing and safety

The wellbeing of employees and safety in the workplace should be the number one concern of all employers. Considering the impact that HAND can have on safety in the workplace and quality of work (greater absenteeism, increased mortality, depression and anxiety), it cannot be ignored by employers.

As HAND is associated with poorer adherence to ARV-treatment schedules, it further compounds such issues. Ignoring HAND would thus be to the detriment of both worker and employer. Furthermore, as the population of people living with HIV/AIDS get older, we need to pay close attention to the effects of ageing in this population as the HI-Virus ages the brain prematurely, which may in itself lead to the presence of early cognitive deficits.

What can be done?

In most individuals, the symptoms of HAND can be reversed or at least halted. Only a small percentage of individuals continue to decline after starting ARV treatment. There is good evidence that patients who receive early treatment perform better in the long run. Thus the key to improvement is early detection and treatment.

Since there is no biological marker for HAND at this stage, symptoms can only be detected by screening for HAND, which should be part of standard care, and referral to a neuropsychologist for a full assessment should symptoms be detected. For people who are living with HIV/AIDS who are already on ARVs and have HAND, drugs that are better at penetrating the central nervous system can be prescribed. Even though we don’t have much information at this point regarding success of rehabilitation in this group of people, the possibility of rehabilitation cannot be excluded.

Detecting HAND early gives the employer the opportunity to initiate ARVs in the early stages of the disease, frequently when the CD4 count is still high. Employees can then also be monitored to see if they are work fit. Should they not be work fit, they can then be redeployed. Similarly, employees with mild impairment but who are functional can be monitored on a regular basis, making sure that they do not become a safety risk. This model protects both employee and employer.

Further implications

To get back to our hypothetical situation with Mr Nonama: if he was suffering from HAND, and had no insight into his condition, it could to some degree explain the risks that he took driving that day. Not only would his ability to make rapid decisions have been affected,  but so too his reaction time, his attention to what was going on around him, and his ability to try to come up with a compensatory plan. The possibility of him successfully managing a situation in order to avoid an accident if he had HAND would have been greatly reduced. Had he been tested and diagnosed with HAND, he may not have been behind the wheel at all.

Other than the immediate results of this tragic incident, however, there are numerous other implications for drivers and employers alike. Who is liable in the case of an accident when a driver has HAND? Does liability lie with the employer who put an unfit driver on the road, or the driver, who may not have proper insight into his or her condition? Management, safety and deployment of drivers are some issues that need to be seriously considered in light of this. Screening for HAND should be part of every wellness programme. With proper care and procedures, accidents can be minimised and a healthy work force can be maintained.

Research

Dr. Hetta Gouse (Ph.D.) is a consultant neuropsychologist and researcher at the University of Cape Town.

The GSH-HIV Mental Health Group is in the process of setting up a research project to assess the effects of HAND in truck drivers in South Africa. We are looking for a corporate partner. Should parties be interested, please contact Dr. Hetta Gouse at hetta.gouse@uct.ac.za

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