When should a person stop driving? As our population ages and the number of associated health conditions increase, this question is being asked with increased frequency. Progressive licensing agencies recognize that age and medical diagnosis alone are insufficient indicators of driver fitness. The Oregon DMV has, for example, determined that only those conditions which are “severe and uncontrollable” require license revocation. This is the case if the impairment is not correctable by medication, therapy, or surgery; or by driving device or technique. Medical conditions which impair driver fitness may either be episodic or chronic, functional or cognitive.
Episodic impairments are sporadic and unpredictable. Total loss of consciousness or alteration of perception short of loss of consciousness, may be due to primary central nervous system disease such as a seizure disorder. Diabetic hypoglycemia, renal hypertension, and thyroid disease are examples of clinical conditions which are not primary to the central nervous system but can lead to alterations in consciousness. These and other diseases have as their common effect on safe driving episodic alterations of consciousness. There, generally, is no question that when the event occurs, the individual is not competent to drive.
Unlike the episodic outcomes of medical conditions, chronic outcomes are more stable and enduring. Whether chronic or episodic, impairments affect either functional or cognitive abilities. Functional impairments include both sensory and motor impairments. Sensory impairments are defined as those conditions which affect peripheral sensation of extremities, including but not limited to: tingling and numbness and loss of position sense in extremities affecting the ability to feel, grasp, manipulate or release objects or use foot controls effectively. Motor impairments affect strength, flexibility, and/or motor planning and coordination.
Cognitive impairments may adversely affect or manifest the following: attention, judgment and problem solving, reaction time, planning and sequencing, impulsively, visio-spatial, memory, loss of consciousness or control.
Family members, physicians, and policy-makers have a responsibility to monitor driver fitness and establish guidelines to ensure both safety and mobility.
