Thursday, November 4, 2010

I forgot to apply my brakes !!

The population with dementia is increasing ...and will probably increase for ever! An interesting article from Alzheimers association showed that the health care cost for managing dementia is almost thrice the profit of Walmart! Anyway our topic is not that. I had a patient today brought by his son, who takes care of dad's finances. His Mini mental state exam(MMSE) was 22, and the question of driving came up. Can this patient drive with this MMSE score? or will he forget to apply his brakes one day ?!!

First of all ......MMSE alone cannot be used to assess driving. It has a low sensitivity when used alone assess suitability of driving. A score of <25 is possibly useful in this aspect according to the latest guidelines from American Academy of Neurologist(AAN April 2010). If its not MMSE ..what predicts safety of driving?

Based on a number of studies Clinical Dementia Rating (CDR)scale appears to be useful for predicting unsafe driving. CDR mainly relies on memory ,but also has other factors like orientation, judgement, personal care, home& hobbies etc(altogether memory is the major category...with other 5 as secondary categories). A score of  0.5 to 1 may predict unsafe driving ....but it has a wide confidence many pts with that score passed the on road driving test(which is best at predicting unsafe driving........unfortunately can't be done in the office!!!)
The Academy of Neurology has the following as recommendations...

The CDR scale (Level A)
• A caregiver’s rating of a patient’s driving ability as marginal or unsafe (Level B)
• A history of traffic citations (Level C)
• A history of crashes (Level C)
• Reduced driving mileage (Level C)
• Self-reported situational avoidance (Level C)
• MMSE scores of 24 (Level C)
• Aggressive or impulsive personality characteristics (Level C)

Factors not useful in assessing safe driving are

• A patient’s self-rating of safe driving ability (Level A)
• Lack of situational avoidance (Level C)

Our gentleman had CDR score of 1, with a marginal caregiver rating, situational avoidance. He was advised to stop driving. Hope he doesn't forget this advice!