RESNA 26th International Annual Confence
THE RELATIONSHIP OF HEALTH STATUS, FUNCTIONAL STATUS, AND PSYCHOSOCIAL STATUS TO DRIVING AMONG THE ELDERLY WITH DISABILITIES
Americans, young and old alike, depend on the automobile for 90 percent of their travel needs, making driving an important activity of daily living [1]. With aging, physical and/or cognitive limitations may impede an older person's driving abilities. This study examines differences among frail elders who continue to drive, have ceased driving, and never drove. Applications of assistive technologies, which may enable the elderly to drive safer for a longer period of time, are then discussed.
The older population represents the fastest growing portion of American people. Persons over 65 years of age comprised 13% of the total population in 2000, and this figure is expected to rise to 20% in 2030, representing about 70 million older persons [2]. It has been estimated that one of four drivers in the U.S. will be over the age of 65 in 2024 [3].
Characteristics of the elderly driver: Physical, sensory, and cognitive changes occur during the normative aging process, affecting the performance of everyday tasks, including driving [4], [5]. When individuals recognize diminished capacities, many adjust their driving behaviors and some cease driving altogether [4]. Older drivers are more likely to make fewer trips, travel fewer miles, and avoid highway driving. Other methods of self-regulation include not driving after dark, avoiding rush hour traffic, and choosing not to drive during inclement weather. Age alone has not been found to be a reliable predictor of driving ability or the likelihood of being involved in a motor vehicle crash as problems with the skills required for driving may occur at any age [6], [7].
Health status related to driving: In addition to the motor, sensory, and cognitive declines that are associated with age, the elderly are more likely to experience chronic medical conditions and use medications that may adversely affect driving abilities [5]. Some studies of health and driving status show a strong correlation between driving cessation and visual impairments [8], [13].
Functional status and driving: Physical abilities such as trunk stability, strength, endurance, and coordination are essential to performing the tasks of driving, such as holding and manipulating the steering wheel and using the pedals and other vehicle controls [9]. Maneuvering a motor vehicle becomes more difficult for older drivers as muscles lose strength, bone density decreases, and joint flexibility diminishes [10]. Difficulties with the automobile itself may prevent some elderly from driving. Common problems include difficulty entering and exiting, seating, storage for mobility devices, and seat belt use [11]. Drivers with limited flexibility and range of motion in the legs, arms, and neck may be at increased risk for crashes [6].
Mental/Psychosocial status and driving: The loss of a driver's license can affect one's quality of life and self-esteem [12]. Isolation resulting from restricted mobility may act to accelerate additional declines in health and psychosocial function, and have linked driving cessation with increased depressive symptoms [1], [13]. Cognitive tasks required for driving include: 1) access and retrieval of information to navigate and maintain vehicle control; 2) visual search and scanning with the ability to discern the most relevant information for safe motor vehicle operation; and 3) divided attention, or the ability to process and respond to the most important stimuli [10]. The aging process may affect the performance of all three of these cognitive tasks.
The primary research activity of this project was to examine the differences in health status, functional status, and psychosocial status among frail elders who: 1) continued to drive; 2) elders who had stopped driving; and 3) elders who had never driven an automobile. This information holds value for those professions that develop, implement, and train users of assistive technologies to enable the elderly to drive safely for a longer period of time, thus maintaining independence and autonomy.
This report is based on the Rehabilitation Engineering Research Center on Aging, Consumer Assessments Study (CAS), a longitudinal study of the coping strategies of elders with disabilities. The Transportation Section of the CAS was administered to 697 subjects. The CAS used a battery of instruments to measure multiple dimensions including health status, functional status, and mental and psychosocial status.
Of the participants that completed the Transportation Section of the CAS, 40.3% continued to drive, 44.2% had ceased driving, and 15.5% had never driven. Of those who ceased driving, 49.8% indicated that they would like to drive again. Forty-four point three percent of the participants who were still driving reported that they do not drive at night.
Significant differences in health status were found among the three groups for vision, perceived need for additional medical treatment, number of medications, for days spent in a nursing home or rehabilitation center, and total number of illnesses. Those who continued to drive had better vision, fewer number of illnesses, spent fewer days in a nursing home or rehabilitation center, and took fewer medications.
Significant differences were found for all functional status measures. The group of participants tha continued to drive demonstrated the highest level of functional status, with less variance within the group,
There were significant differences for all mental and psychosocial measures. Higher levels of mental functioning were found in the group that continued to drive for both the Mini Mental Status Exam and the Cognition portion of the Functional Independence Measure, with less variance within the driving group than the stopped driving group and the never drove group.
Many Americans must cease driving due to health problems and decreases in functional status, which adversely affect psychosocial status. This illustrates the need to provide options that would enable the elderly to remain mobile. One of these options would be to provide technology to compensate for decreases in abilities.
Assistive technology may enable older drivers to drive safely for a longer period of time. These technologies range from simple, low-tech vehicle modifications to high-tech automated system controls. Modifications for functional limitations due to aging or disease include mechanical or servomotor hand controls for accelerator and brake function; spinner knob or joystick controls for steering; and other aids to assist with manipulation of keys and secondary vehicle controls [14]. Vans are often customized to accommodate those with more limited abilities. Placement of special mirrors may accommodate limitations in scanning ability due to visual or physical deficits.
More advanced technologies are being developed to automate many of the tasks of driving. These technologies include within-vehicle systems and systems that communicate with other vehicles and the infrastructure. Collision avoidance systems may monitor location and motion of vehicles, obstacles, and pedestrians in front or behind equipped vehicles. Some of these systems monitor lane changing/merging and intersection negotiation. System response to adverse conditions could range from simple auditory or visual notification to the driver to automation of braking and steering functions. Infrared vision enhancement systems hold promise to compensate for decreased nighttime vision. Traveler information systems, which utilize navigation and route guidance to locate a destination or avoid congested areas, may also assist the elder driver [15].
This research was supported through funding from the National Institute on Disability and Rehabilitation Research of the U.S. Department of Education and the Administration on Aging of the Department of Health and Human Services.
Dennis P. McCarthy,
M.Ed., OTR/L
University of Florida
P.O. Box 100164
Gainesville, FL 32610-1042
(352) 846-1018: dmccarth@hp.ufl.edu