Medical Conditions and Driving: A Review of the Literature (1960  2000)
TRD Page
Foreword
Acknowledgements
Section1: Introduction
Section 2: Vision
Section 3: Hearing
Section 4: Cardiovascular
Section 5: Cerebrovascular
Section 6: Peripheral Vascular
Section 7: Nervous System
Section 8: Respiratory
Section 9: Metabolic
Section 10: Renal
Section 11: Musculoskeletal
Section 12: Psychiatric
Section 13: Drugs
Section 14: Aging Driver
Section 15: Anesthesia and Surgery
Appendix A
List of Tables
List of Figures
download PDF

Section 3: Hearing

Prevalence

According to recent statistics, more than 20 million people, or 8.6 percent of the total population in the United States 3 years of age or older, have hearing problems (National Center for Health Statistics, 1994). A similar rate is reported in Canada with the incidence of hearing loss in the Canadian population estimated to be 10 percent (Statistics Canada, 1996). As with visual deficits, impairments in hearing are strongly associated with age. The estimated prevalence of hearing impairments as a function of age is shown in Table 2.

Table 2  Estimate of the Prevalence of Hearing Impairments by Age Group, United States, 1990-1991

Source: National Center for Health Statistics, Data from the National Health Interview Survey, Series 10, Number 188, Table 1, 1994 (Reproduced with permission)

Age Group

Percent of Population

3-17 years

1.8

18-34 years

3.4

35-44 years

6.3

45-54 years

10.3

55-64 years

15.4

65 years and older

29.1

Total

8.6

As can be seen in Table 2, individuals 65 years of age and older are eight times more likely to have a hearing impairment than individuals 18-34 years of age. The prevalence of hearing impairment also differs as a function of gender. Males of all ages are more likely to have a hearing impairment (10.5 percent for males and 6.8 percent for females) and the gap widens after age 18 (National Center for Health Statistics, 1994). The gender differences in the prevalence of hearing impairment have, for the most part, been attributed to occupational differences in noise exposure. However, recent longitudinal research has revealed more rapid declines in hearing sensitivity in males not involved in occupations with high noise exposure (Pearson, Morrell, Gordon-Salant, et al., 1997).

Hearing and Driving Literature Review

Despite the importance of auditory information for driving (e.g., auditory feedback regarding operation of the motor vehicle, mechanical failure, awareness of other road users through detection of road noise, horn honking, etc.), there are few data to indicate that impairments in hearing affect driving ability. Results from an early study by Coppin and Peck (1963) indicated that deaf people, as a group, had poorer driving records than non-deaf people. However, more recent studies have failed to provide convincing evidence that individuals with hearing impairments are at a higher risk for motor vehicle crashes. In 1994, McCloskey, Koepsel, Wolf, and Buchner conducted a population-based case control study to determine whether sensory impairments place older drivers at risk for collision injuries. The cases were drivers who sought medical care, within 7 days, for injuries sustained in a police recorded motor vehicle crash. Controls were selected from a pool of eligible subjects who had not been injured in a police reported motor vehicle crash. Driving exposure, based on self-report, was similar for both groups. Sensory impairment data were extracted from medical records. Results of their investigation revealed no significant increase in risk of injury from motor vehicle collisions as a function of hearing impairment (See Table 3). However, those using hearing aids were at increased risk of an injury collision. The authors speculated that feedback from the hearing aid while driving may create a distraction, placing the driver at an increased risk of crash involvement. However, an analysis was not conducted to determine who was at-fault.

Table 3  Risk of Injury from Motor Vehicle Crash Associated with Impaired Hearing

(Re-produced in part, from McCloskey, L.W., Koepsell, T.D., Wolf, M.E., & Buchner, D.M. (1994). Motor vehicle collision injuries and sensory impairment of older drivers. Age and Ageing, 23, 267-273, by permission of Oxford University Press)

Condition

# with Valid Data

Percent with Condition

Risk Estimates

 

Cases

Controls

Cases

Controls

RR

CI

Hearing Impairment (ever diagnosed)

234

446

27.3

22.4

1.3

0.9-1.8

Hearing Aid:

Prescribed

234

446

14.2

12.1

1.2

0.8-2.0

    Owned

233

448

19.7

13.8

1.6

1.1-2.6

    Owned and worn for driving*

215

423

13.0

8.7

1.9

1.1-3.3

    Owned but not worn for driving*

204

409

8.3

5.6

1.7

0.8-3.6

* versus non-owners

Gresset and Myer (1994) conducted a case-control study investigating the relationship between impairments or chronic medical conditions and motor vehicle crashes. The sample consisted of 1,400 elderly male drivers (all aged 70) who had had a crash resulting in mild bodily injury or property damage between 1988 and 1989.Compared to same aged controls, cases with hearing impairments were not at increased risk for crashes (OR = 0.90, CI = 0.65-1.24). Importantly, male drivers involved in crashes causing death or causing severe bodily damage were excluded from the study. Exclusion of those cases may have led to an underestimation of the true relative risk of crashes, particularly for crashes associated with other medical impairments (e.g., cardiovascular disease, diabetes mellitus).

More recently, Ivers, Mitchell, and Cumming (1999) examined the association between vision, hearing loss, and motor vehicle crashes in a cross sectional survey of 2,379 current drivers. Self-reports were used to assess hearing loss and motor vehicle crashes. Thirty-eight percent of the sample reported having hearing loss. 5.6 percent of individuals aged 49 to 79 reported being in a crash, with 9.1 percent of those 80 years of age and older reporting crash involvement.

Moderate hearing loss (adjusted prevalence ratio PR =1.9) and hearing loss in the right ear (PR = 1.8) were associated with an increased crash risk. Although not significant, those with severe hearing impairment also showed an increased risk for crash (PR = 1.5). It is important to note that indices of hearing loss and motor vehicle crashes used in this investigation were based on self-reports.

Back

Top

Next