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Driving Impairment and ADHD

Driving Impairment and ADHD. Melissa K. Stern. Adolescent ADHD. ADHD is defined by two distinct symptom areas Hyperactivity/Impulsivity Attention Diagnosis Includes Impairment Gross motor symptoms often decrease with age Impairment associated with other symptoms does not decrease.

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Driving Impairment and ADHD

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  1. Driving Impairment and ADHD Melissa K. Stern

  2. Adolescent ADHD • ADHD is defined by two distinct symptom areas • Hyperactivity/Impulsivity • Attention • Diagnosis Includes Impairment • Gross motor symptoms often decrease with age • Impairment associated with other symptoms does not decrease

  3. ADHD and Impairment • In childhood, focus is on peer, family, and academic impairment (Pelham, 2005) • This impairment is not a direct cause of death • Demands of attention in school and the workplace increase with age • Impairment due to ADHD symptoms may have more severe (fatal) consequences in adolescence and adulthood • Driving • This form of impairment can affect everyone, not just the person with ADHD

  4. Some Basic Numbers • 7,460 15-20 year-old drivers involved in fatal MVAs in 2005. • Driver fatalities up by 4% from 1995-2005 • For males, driver fatalities have increased by 5% • For females, 1% decrease • 3,467 15-20 year-old drivers killed, 281,000 injured in 2005 • Leading cause of death for 15-20 year olds? • MVAs NHTSA, 2006

  5. MVAs • Causes of MVAs are considered to be behaviors associated with typical adolescent behavior (Brown, Sanders, & Schonberg, 1986) • What is one of the most common causes of MVAs? • Inattention (Lamm, 2002)

  6. Driving and Psychological Disturbances • Adults with psychiatric conditions in general are at greater risk (Kastrup et al., 1988; Noyes, 1985) • Behaviors identified as specific risk factors more common in those with ADHD (Deffenbacher et al., 2003; Jonah, Thiessen, & Auyeung, 2001; Shope, Raghunathan, & Patil, 2003). • Being male • Antisocial Behaviors • Sensation seeking • Aggression

  7. Food For Thought • How would you feel if you knew an adult with ADHD was a commercial truck driver? • Consider the policy/industry/insurance implications as we go through the following slides

  8. The First Longitudinal Follow-up • Self-report • Found that more hyperactives had been in car accidents compared to controls Weis et al., 1979

  9. ADHD and Driving • Self-report, parent-report, and review of official DMV records indicate adolescents with ADHD have evidence of significantly more dangerous driving behaviors than community controls (speeding, crashes, citations, etc) (Barkley, 1993; Nada Raja et al., 1997) • Research with adults has indicated this phenomenon continues past adolescence (Barkley, 2002)

  10. Driving Simulators • Researchers have moved from self-report to driving simulation tasks (Barkley, Murphy & Kwansik, 1996; Barkley et al., 2002). • Have investigated specific driving behaviors during simulation tasks • Speeding, average brake reaction time, consistency of reaction time, steering wheel angle, • Results inconsistent • Quality of simulator?




  14. SmartCar • Created for use by National Older Driver Research and Training Center (OT Department) • Virtual Reality Simulator • 180 degree forward visual field-of-view (displays virtual objects behind car as well) • Three connection flat screens • Perceptual filling after several minutes and drivers do not notice partitions of 3 segments • 3 LCD projectors on ceiling

  15. SmartCar • Simulator is 1997 Dodge Neon • Normal brake, accelerator, signalizing and steering controls • Driver provided with apparent longitudinal and lateral movement, allowing driver to speed up/slow down • Simulator also includes steering force/feel feedback • Road feel captured by low-frequency audio woofer and amplifier

  16. SmartCar • Also includes auditory simulation • Audio components produce engine, transmission, and road noise at varying intensities and frequencies • Tire screeches associated with heavy braking or high cornering loads • Horn • Turn indicators • External crash sounds, siren sounds, tire noise that can discriminate between on- and off-road surfaces

  17. Motion Sickness • Happens frequently in virtual reality tasks • Can be decreased using certain methods • Use of habituation task to familiarize participant with simulator • Room temperature of 68 degrees • Motion Sickness Bands • Fans • Issue with motion sickness/attrition

  18. ADHD and Driving: Documenting Effects • Do subtype differences exist? • Does stimulant medication increase performance during a simulated driving task? • How does alcohol interact with impairment already present in ADHD? • How does ADHD and the disruptive behavior disorders affect road rage? • Does ADHD, above and beyond ODD and CD, account for differences in simulator performance?

  19. Subtype Differences • Two Studies have investigated • Conflicting results • Issues in adolescent/adult subtyping • (Barkley, 2002; Cox et al., 2004)

  20. Stimulant Medication • Researchers have looked at Strattera & Ritalin • Poor Results for Strattera • Variable results for Ritalin • Issues include only form of remediation is medicine, time of day accidents occur (Barkley et al., 2005; Barkley et. Al, 2007; Cox et al., 2000; Cox et al., 2004)

  21. Alcohol & ADHD • 50 Adults with ADHD and 40 Controls • Half randomly given alcohol until legally “drunk” (.04 BAC) and half “double drunk (.08 BAC) • Completed CPT and Simulator Task • Outcome: Alcohol is bad when mixed with driving! • (Barkley et al., 2006)

  22. ADHD & Road Rage • Researchers compared college students with high and low symptoms of ADHD • Students High on ADHD symptoms reported: • More driving anger • Display anger in more hostile/aggressive ways • More aggressive and risky on the road • Experience more crash-related outcomes • More generally angry in life • Tend to display anger in socially unacceptable ways Richards, Deffenbacher, & Rosen, 2002

  23. Is ADHD the real problem, or is it comorbidity? • Several studies have assessed relative contribution of ADHD, ODD, CD, and depression to driving impairment • In general, studies have found ADHD, above and beyond comorbidities, to be associated with poor driving history • ADHD plus ODD/CD compounds likelihood of drinking and driving, driving without a license, and other serious offenses Barkley et al., 2002; Barkley et al., 2005; Barkley & Cox, 2007

  24. Manual Vs. Automatic • One study has looked at driving performance on manual versus automatic transmission • Found fewer mistakes/speeding occurred when driving manual transmission Cox et al., 2006

  25. ADHD and Driving: Mechanistic Investigations • Does driver knowledge account for differences in performance? • Inconsistent results (Barkley, Murphy, & Kwansik, 1996; Barkley et al., 2002) • Deficiencies in Michon (1979) driver performance hierarchy

  26. Michon’s Driver Hierarchy • Level 1 • Attention, concentration • Level 2 • Executive functioning, inhibition • Level 3 • Planning abilities and complex executive tactics Adolescents with ADHD demonstrate impairment with all three of these types of functioning outside of driving tasks (Barkley et al., 1991; Seidman, 2006).

  27. Testing the Hierarchy • In 2002, Barkley looked at each level using various tests of executive functioning, visual attention, and a driving simulation task • Found some visual deficits during a scanning task but could not explain them (unilateral) • Concluded no perceptual impairment but ADHD group demonstrated impairments in attentiveness and rule-following. • Perceptual conclusions based on basic visual scanning tasks

  28. Summing Up: A meta-analysis • Completed PsychInfo and Pubmed search for articles • Evaluated relationship between ADHD status and various driving behaviors/outcomes • Found overall support for higher risk of MVC’s for people with ADHD • Support for Ritalin vs. Straterra or Adderall Jerome, Segal, & Habinski, 2007

  29. Limitations of Previous Studies • Sample sizes • Attrition • Method of Diagnosis • Method of Driving Assessment • Confounds • All stimulant studies industry sponsored

  30. What We Don’t Know

  31. Gaps in the Literature • Adequacy of simulators used to document driving behaviors • Mechanistic aspects of differences in driving behaviors between adolescents with and without ADHD • Problems with peripheral vision/functional field of vie in new (adolescent) drivers

  32. Functional Field of View • Defined as the angular extent of the observable world that is seen at any given moment • Range of visual abilities is not uniform across a field of view • Novice drivers are more likely to have poorer peripheral acuity which is associated with a greater frequency of accidents

  33. ADHD versus Older Adults • ADHD characterized as disorder of executive function • Similar to problems healthy older adults • Research on natural effects of aging on cognition show many older adults have age-related impairment in distractibility, sustained attention, and planning/org due to deterioration of frontal lobe • These deficits linked to increase in MVC’s Chao & Knight, 1997; Daignealt, Braun, & Whitaker, 1992; Mittenberg, Seidenberg, O’Leary, & diGiulio, 1989 ; Tucha et al., 2007

  34. Filling in One Gap: On-Road Research • Most recently, researchers have completed multi-method battery including self-reports, simulated driving, and closed course driving tasks • When judged by licensed driving instructor, compared to controls, adults with ADHD were judged to make more impulsive errors during on-road driving Fischer et al., 2007

  35. My Research • Assessing Mechanistic underlying mechanisms • Assessing whether errors are more impulsive or inattentive • Nonlinear methods (differences in speed variability)

  36. Future Directions • Identify mechanistic factors involved in driving behavior differences in adolescents with ADHD • Can create attentional training programs from data • Continue parsing apart effects of ADHD, ODD, CD • More medication effect studies • More research on manual/automatic effects • Developing standardized driving assessment/screening tool • Assessing FFOV differences/complexities

  37. More Future Directions • Cell Phone use • Radios • Multiple persons in the car • Eating/Drinking (non-alcoholic) while driving • Using a map

  38. Discussion and Implications • Should ADHD drivers pay higher fees unless on stimulant medication? • Should they have to register their diagnosis, as is currently required in Canada and Australia? • Should they be turned down from certain jobs (e.g. truck driving) because of such a diagnosis?

  39. Questions?

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