The impaired older driver.

• There is no doubt that older people can still drive cars safely, even into their 90’s.

• Driving is very much a cognitive and visual processing exercise.

• You must have normal brain function and quick reflexes to be able to drive a car safely.

• You also need good hearing to be aware of your surroundings, good neck movements to check for blind spots and good trunk rotation to check behind.

• However, crash statistics show generally that drivers aged 85 or older have amongst the highest per kilometre crash rates and driving fatality rates. 

• When the distance travelled by certain age groups is taken into account the older driver’s fatality rate escalates to levels equivalent to, and for females higher than, the levels of the 15-24 age group, the highest crash risk group.

• The older driver’s accident risk also tends to increase with increasing age.

• The high fatality rate amongst older drivers is due to their increased frailty and consequently a greater risk of crash injuries resulting in death.

• Driver over 85 years of age suffer more severe injuries at lower crash velocities and with minor crashes.  They are generally over-represented in traffic accident statistics and the fatality rate for these older drivers is about 17 times higher than the rate for 25-65 year old age groups.  Drivers 65 years and older make up about 15% of the population but are  involved in about 20% of fatal crashes and 17% of pedestrian fatalities.

• Older drivers tend to be involved in-

  • multi-vehicle crashes,

  • angle crashed (T-bone hit from the side)

  • crashes occurring during the daylight hours of weekdays,

  • occurring at intersections and other complex traffic situations like roundabouts,

  • while travelling at lower speeds,

  • involving failure to give way,

  • improper turns,

  • disregarding traffic signals

• Older drivers are much more likely to be the cause of crashes than any other age group.

• Impaired older drivers are reluctant to give up their driving licence due to poor health because of lack of insight into their impairments. This is particularly so with dementia.

• Drivers with dementia have at least 5 times higher risk of fatal crashes than aged-matched non-demented drivers. They have 13 times higher intersection crash rate than older drivers with normal visual attention.

• Selective attention, especially rapid shifting of selective attention is impaired in early Alzheimer’s dementia and is related to increased crash risk even in those drivers with the early stages of Alzheimer’s dementia.

• Older drivers with poor mental state and UFOV (Usual Field of View) have 4 times higher accident rate and 13 times higher intersection crash rate.

• UFOV measures the speed of visual processing for rapid detection and localisation of targets under conditions of divided visual attention and in the presence and absence of visual clutter, similar to complex traffic situations. UFOV is a measure of processing speed that predicts driving performance and other functional abilities in older adults. The UFOV test measures the amount of information someone can extract from a visual scene in one glance. Its scores show relatively strong relationships with everyday activities and crash risk. The UFOV test consists of three computer tests to measure processing speed and central vision, divided attention, and selective attention. Processing speed scores indicating a 40% or greater reduction in useful field of view signal cognitive performance concerns. 40% was chosen as the threshold because it is the point of greatest increase in crash frequency.

• There is now quite strong evidence that the risk of motor vehicle accidents for drivers with dementia is significant, even in the early stages and gets worse as the disease progresses.

• This is not surprising, as even in early Alzheimer's dementia the patient would have had the  neuropathology developing in their brain for at least 3 years prior to presentation to me.  By the time they see me they usually have significant impairments in short-term memory, in other domains of the brain, and day-to-day living functions.

• Many studies of driving with cognitive impairment consistently demonstrate impaired performance in patients with dementia, compared to normal elderly drivers.

• Most elderly patients with Alzheimer's dementia lack insight into their cognitive impairments.  They do not understand this. This is why self-assessment of driving doesn’t work here!

• Similarly, many relatives also are unaware that driving is very much a cognitive or mental activity and they can't reconcile the fact that someone who is cognitively impaired or confused should not be allowed to drive a motor vehicle. 

• Driver with dementia must NOT be allowed to drive motor vehicles.

• These bad crash statistics for older drivers likely include most of the impaired older drivers.

• COGNITIVE FUNCTION IS ESSENTIAL FOR SAFE DRIVING

   These are impaired in somebody with Alzheimer’s dementia and they include:

   ·      Speed of thinking/information processing.

  ·       Reaction time/reflexes.

  ·       Left/right orientation.

  ·       Geographic orientation.

  ·       Impulsivity and control of their emotions and reflexes.

  ·       Visual vigilance/concentration.

  ·       Not being easily distracted.

  ·       Managing dual simultaneous stimuli.

  ·       Sustained attention.

  ·       Divided attention.

  ·       Switching attention.

  ·       Responding to visual stimuli.

   These are the reasons why people with even mild, early Alzheimer’s dementia cannot drive a car safely.

For more information read Dr Peter Lipski’s book “Your Elderly Parents Failing Health. Is It Ageing Or A Treatable Condition”.