Self-Reported Driving Habits in Subjects With Persistent Whiplash-Associated Disorder: Relationship to Sensorimotor and Psychologic Features

Article Outline

• Abstract
• Methods
  • Participants
  • Questionnaires
    • Neck Disability Index
    • General Health Questionnaire
    • Impact of Events Scale–Revised
    • Tampa Scale for Kinesiophobia
    • Driving Habits Questionnaire
  • Physical Measures
    • Cervical ROM
    • Cervical joint position sense
    • Smooth pursuit neck torsion test
  • Data Management and Analysis
• Results
  • Sample Characteristics
  • Modified DHQ
    • Current driving
    • Assistance and confidence
    • Exposure
    • Avoidance
    • Driving space
  • Physical Measures
  • Relations Among Physical Measures, Self-Reported Driving Ability, and Psychologic Features
• Discussion
  • Study Limitations
• Conclusions
• References
• Copyright

Abstract 

Pereira MJ, Jull GA, Treleaven JM. Self-reported driving habits in subjects with persistent whiplash-associated disorder: relationship to sensorimotor and psychologic features.

Objectives

To study self-reported driving habits after whiplash injury and to determine any relation among self-reported driving habits, selected sensorimotor impairments, and psychologic features.

Design

Repeated-measures, case-controlled.

Setting

Tertiary institution.

Participants

Subjects (n=30) with chronic whiplash and 30 asymptomatic controls.

Interventions

Not applicable.

Main Outcome Measures

The Driving Habits Questionnaire (composite driving tasks score), Neck Disability Index (NDI), 28-item General Health Questionnaire (GHQ-28), Impact of Events Scale−Revised (IES-R), Tampa Scale for Kinesiophobia, cervical range of motion, cervical joint position error, and smooth pursuit neck torsion test.

Results

Subjects in the whiplash group had equal driving exposure and driving spaces (distances, locations) compared with control subjects but reported significantly more driving difficulty with most driving tasks (P<.01). There were no significant correlations between the composite driving tasks score and any of the sensorimotor impairments, but there were significant and moderate correlations between the composite driving task score and both pain and disability (NDI score, .518) and anxiety (GHQ-28 score, .518; IES-R score, .524).

Conclusions

Persons with chronic whiplash have greater self-reported driving difficulty than controls, which appears to relate more to reported levels of pain and disability and psychologic stress than laboratory measures of features of cervical sensorimotor control.

Key Words: Rehabilitation, Stress, psychological, Whiplash injuries

MANY PEOPLE WITH PERSISTENT neck pain after a whiplash injury report problems with activities of daily living. Difficulties with driving are one of the most commonly reported problems.¹ Studies of people who have been involved previously in a motor vehicle collision (MVC; not necessarily causing a whiplash injury) report a general lack of confidence and anxiety with driving, changes to their driving behavior, and limitations on their travel.², ³ To date, no studies have looked specifically into the driving practices of subjects with persistent whiplash-associated disorders.

Driving is a functional task that imposes cognitive, automatic, physical, and psychologic demands on a person. From a local psychophysic perspective, driving is dependent on the precise coordination of eye movements with both small and large neck movements. Deficits in cervical range of motion (ROM),⁴, ⁵ neck-influenced eye follow measured with the smooth pursuit neck torsion test,⁶, ⁷ and cervical joint position sense⁸, ⁹, ¹⁰ have been identified in those with chronic whiplash-associated disorder. These impairments may affect the ability to move and control the head and eyes and the position of the head in relation to the trunk and could have an impact on driving habits. There is evidence to show that ocular disturbances and decreased neck movement influence driving in other populations such as persons with ankylosing spondylitis, persons with rheumatoid arthritis, and the elderly.¹¹, ¹², ¹³, ¹⁴ Thus, it is conceivable that subjects with chronic whiplash-associated disorder may have altered driving patterns because they have similar impairments. Gimse et al¹⁵ investigated driving skills in those with chronic whiplash-associated disorder and showed decreased reaction times and steering precision in response to traffic sign recognition. This was shown to relate specifically to abnormalities in the physical measure of neck-influenced eye follow as tested with smooth pursuit neck torsion. However, no other studies have investigated driving habits in subjects with persistent whiplash-associated disorder or considered the relation between driving habits and signs of sensorimotor impairment.

Persons with chronic whiplash-associated disorder have also been shown to have decreased psychologic health associated with elevated levels of fear avoidance and both general psychologic distress and traumatic stress related to their accidents.¹⁶, ¹⁷ Specifically, greater stress relating to the accident has been shown to be associated with a poorer long-term outcome after a whiplash injury.¹⁸ Thus, psychologic factors could also be contributing to problems with driving in those with chronic whiplash-associated disorder.

The aim of this study was to compare driving habits between subjects with chronic whiplash-associated disorder and asymptomatic controls and to determine whether there were any relations among head and eye movement impairments, psychologic features, and self-reported driving ability. We hypothesized that people with persistent whiplash-associated disorder have differences in their self-reported driving ability compared with asymptomatic controls. We also hypothesized there would be a strong relation between self-reported driving ability and deficits in sensorimotor tasks and psychologic status.

Back to Article Outline

Methods 

Participants 

Sixty subjects were recruited for the study. The whiplash-associated disorder group consisted of 30 current drivers with chronic neck pain attributed to an MVC at least 3 months postinjury. The asymptomatic control group included 30 current drivers with no history of neck pain or trauma. Subjects in both groups were required to be between the ages of 18 and 55 years and legally licensed to drive. Control subjects were recruited from staff and students of the university and the general public through advertisements on notice boards and in the university newspaper. Subjects with whiplash were volunteers recruited from patients who attended a university whiplash research unit and through advertising in the local newspaper. Subjects were excluded from the study if they had any of the following: previously diagnosed vestibular dysfunction or any associated diseases; positive Dix-Hallpike maneuver, which excluded subjects with benign paroxysmal positional vertigo as a cause of dizziness; previously diagnosed diseases of the central nervous system; impaired visual acuity or known disorders of eye movement; deafness, hearing aids, or ear surgery (which may implicate the vestibular system); or vascular risk factors such as low or high blood pressure, migraine, known arteriosclerotic disease, or history of dizziness or unsteadiness (whiplash-associated disorder group, any history before the MVC). All subjects were screened for exclusion criteria using an interview. This study was cleared by the institutional human medical ethics committee and was conducted in accordance with the National Health and Medical Research Council guidelines, and all subjects provided informed consent.

Questionnaires 

A series of questionnaires was used to profile the whiplash-associated disorder and control subjects, and measures were taken of pain and emotional distress (general and specific to the accident) and driving history and habits. A general questionnaire recorded information related to the history of the whiplash injury, compensation status, current pain level (visual analog scale), dizziness, and current medications. The questionnaires were as follows.

The Neck Disability Index (NDI)¹⁹ is a validated 10-item questionnaire of pain and functional limitations to determine the disability level associated with the neck pain.

The 28-item General Health Questionnaire (GHQ-28) is divided into 4 subscales: somatic symptoms, anxiety/insomnia, social dysfunction, and severe depression. The total score was used as a measure of general psychologic distress.²⁰

The Impact of Events Scale–Revised (IES-R)²¹ measures current stress relating to a specific incident—the MVC. Three response sets are measured: avoidance, intrusion, and hyperarousal.

The Tampa Scale for Kinesiophobia (TSK)²² questionnaire is an indicator of any fear of movement, which may lead to avoidance of movement.

The Driving Habits Questionnaire (DHQ)¹⁴ is a comprehensive driving questionnaire to assess the driving habits of participants and has been shown to have construct validity and test-retest reliability. This questionnaire documents self-perceived driving habits and limitations and can be used to determine difficulty with driving.

The DHQ provides information on various driving domains and driving habits as well as on factors related to difficulty with specific driving tasks. The DHQ was modified and adapted slightly for this study by adding several questions about driving likely to be challenging to people with whiplash-associated disorder such as reversing, crossing intersections, changing lanes, merging into expressways, and looking out for hazards. It was also tailored to suit the Australian context. All subjects completed the NDI, GHQ-28, and DHQ. Only subjects with whiplash completed the TSK and IES-R because these questionnaires were not relevant to the control subjects.

Physical Measures 

Cervical ROM was measured using a Fastrak.^a One sensor was placed on a lightweight, adjustable headband centered on the forehead of the subject. A second sensor was placed at the level of C7 on the cervical spine using double-sided tape. Subjects were asked to move their heads into neck flexion, extension, and rotation to the left and right. There was 1 practice run in each direction, and each movement was repeated 3 times. The mean of the range in the primary plane was used as the value for each movement direction.

Cervical joint position sense was measured with methodology adapted from Revel et al²³ using the Fastrak as described. Subjects were asked to focus on their natural resting head positions and were then blindfolded. After each test neck movement, subjects returned to the neutral starting position as accurately as possible and indicated yes when they believed they had achieved this position, which was marked on the data recording. A real-time display depicted the actual movement in each direction as well as the original starting position. The joint position error was the difference between the original starting position and the returned head position and was calculated in degrees. Before each subsequent movement, the examiner manually repositioned the subject's head back to the original starting position, guided by the real-time display. One practice movement in each direction was performed. Every subject performed 3 trials each of neck left rotation, right rotation, and extension. The joint position error was the average value of the 3 trials in each primary direction.

Electro-oculography was used to measure and record eye movement while the eyes followed a moving target.^b The measurement procedure was adapted from that described by Tjell and Rosenhall²⁴ and has been described in detail elsewhere.⁶, ²⁵ The target consisted of a laser light driven by a motor to move through a total visual angle of 40° (20° to the left and right of the mid position). The target is electronically controlled to provide a moving sinusoidal stimulus with a maximum velocity of 20° a second and a frequency of 0.2Hz. Pairs of Ag/AgCl surface electrodes^c were placed on the skin just lateral to the eyes bilaterally to record eye movement through changes in the corneoretinal potential. A ground electrode was placed on the forehead. The signals were passed through a 70-Hz low-pass filter and stored on an IBM-compatible personal computer that continually recorded the change in corneoretinal potential and eye position relative to the target during each test sequence. Average velocity of the eye movements, following the target, was calculated by subtracting the corrective movements from the total excursion of the gaze. Square waves were excluded from the analysis. The mean gain (ie, the ratio between the eye movements and of the target) was the measure used to define smooth pursuit movements. The smooth pursuit velocity gain was calculated with the neck in a neutral position, and also with the neck in a torsioned position. The difference between the gain in neutral and the values in torsion was the smooth pursuit neck torsion test difference.⁶, ²⁵

Each subject was seated in a wooden chair with a back support, facing the laser light projected onto a screen, and the test procedure was explained. The skin adjacent to the eyes and forehead was washed, lightly abraded, and swabbed with alcohol. The electrodes were then applied. With the head in a neutral position, subjects were asked to follow the light source with their eyes, keeping the head still. The neck was then kept in a neutral position, and the subject's torso was actively turned to an angle of 45°. In the unlikely event that this angle caused any pain or discomfort, the angle was reduced until these symptoms subsided, and this angle was recorded. A research assistant maintained the head and trunk position. After a short pause, the visual stimulus was presented again and the test repeated. The procedure was repeated in the opposite direction of neck torsion.

Data Management and Analysis 

The GHQ-28, NDI, TSK, and IES-R were scored accordingly. Each subject was also given a composite driving task score that was calculated based on the sum of their answers to the modified DHQ in the avoidance section. For these driving tasks, the response “no difficulty at all” was scored as 0, “a little difficulty” as 1, “moderate difficulty” as 2, “extreme difficulty” as 3, and “have not done this” as 4. A maximum score of 52 indicated maximum difficulty, with higher composite scores indicating greater levels of difficulty. With regard to the difficulty with specific driving tasks, subjects were classified as having any difficulty (score of 1–4) versus no difficulty at all (score of 0) for each task, and the binomial responses for each task were collated.

All data were analyzed by the SPSS package.^d Independent-samples t tests were performed to determine differences between the 2 groups with respect to demographic data, composite driving tasks score, cervical ROM, joint position error, and smooth pursuit neck torsion difference. Pearson chi-square and cross-tabulations were used for analyzing the ordinal data resulting from the individual task responses of the avoidance domain. Spearman correlations were used to determine the relations between self-reported driving ability and the physical and psychologic features within the whiplash group.

Back to Article Outline

Results 

Sample Characteristics 

The demographic characteristics of the whiplash-associated disorder and control groups are presented in table 1. There were no sex differences between the groups, although there were more women in each group. The whiplash-associated disorder group was significantly older (P≤.01) and had more driving experience than the control group (P≤.01). It also had higher levels of neck pain and disability (NDI, P=.00) and general psychologic distress (GHQ-28, P≤.01). There was also a significant difference between the means of the composite driving tasks scores between groups (P≤.01). The whiplash-associated disorder group had a higher composite driving tasks score than the control group. The mean scores for the IES-R and TSK for the whiplash group were 2.2±2.7 and 38±7.8, respectively.

Table 1. Demographic, Physical, Psychologic, and Driving Characteristics of the Control and Whiplash Groups

NOTE. Values are mean ± standard deviation (SD).

Modified DHQ 

The results of the subsections of the modified DHQ are presented in Table 2, Table 3, Table 4.

Table 2. Incidences for Affirmative Answers to Questions Concerning Current Driving and Assistance and Confidence With Driving in the Whiplash and Control Groups

Table 3. Group Comparison and Frequency of Reporting Any Difficulty or No Attempt of the Driving Task

Table 4. Group Comparisons and Frequency of Driving Activities in the Driving Space Areas

Abbreviation: NA, not applicable.

No differences were observed between the groups with respect to wearing corrective lenses to drive, preference for who drove the usual speed of driving, and self-rated driving quality. In the chronic whiplash-associated disorder group, 23% had had someone suggest that they limit their driving (see table 2).

The whiplash-associated disorder group more often reported that they had driven with the help of a passenger (a person who had better visibility and movement than the subject and was riding with the subject in the car) and reported less confidence with driving (see table 2).

The groups had equal driving exposure, with 93% of both groups driving 3 or more days on average a week.

A whiplash injury was significantly associated with difficulty over all driving tasks in the modified DHQ except for driving in the rain (see table 3).

There was a trend for the subjects in the whiplash-associated disorder group to have a larger driving space compared with the asymptomatic group. However, there were no significant differences between the 2 groups for any of the questioned areas (see table 4).

Physical Measures 

The subjects in the whiplash-associated disorder group had significantly less ROM in flexion, extension, and rotation left and right and greater difference in eye follow control in the smooth pursuit neck torsion test than the control subjects. The only difference in joint position error was recorded on return from rotation from the left (table 5).

Table 5. Comparison of Means Between the Whiplash and Control Subjects for the Physical Measurements

NOTE. Values are mean ± SD.

Abbreviation: JPE, joint position error.

Relations Among Physical Measures, Self-Reported Driving Ability, and Psychologic Features 

Correlation analyses were performed between the composite driving tasks score and ROM, joint position error, smooth pursuit neck torsion test, NDI, TSK, GHQ-28, and IES-R to determine whether there were any relations between self-reported driving ability and any physical impairment, self-reported neck pain, fear, general anxiety, or anxiety specific to the collision. Significant and moderate correlations were observed between the composite driving tasks score and the GHQ-28, NDI, and IES-R (all P<0.01) (table 6).

Table 6. Spearman Correlations Between the Composite Driving Tasks Score and Other Measures

Abbreviation: JPE, joint position error.

Back to Article Outline

Discussion 

The results of this study support the hypothesis that subjects with whiplash report altered driving habits with respect to specific driving tasks compared with control subjects. They reported significantly more difficulty with most driving tasks and had higher composite driving tasks scores. Specifically, most subjects with whiplash (>75%) reported difficulty with reversing and reverse parking, and at least half reported difficulty with high traffic volume, rush-hour traffic, expressways, merging, and changing lanes, in spite of the fact that they had more driving experience on average. Generally, it would be expected that more experienced drivers would be more skilled in these tasks and would find the driving tasks easier.²⁶, ²⁷ Yet despite these reported driving difficulties, there was no evidence that the whiplash group altered driving exposure, driving spaces, usual speed of driving, preference for who drove, and self-rating of driving quality.

The subjects with whiplash often used additional assistance with driving from other persons in the vehicle, were less confident, and often reported that someone had suggested they limit their driving. Despite these factors, it seemed that they did not limit their driving. Advice to limit driving is also given to persons with decreased physical function such as older adults, elderly persons with cataracts or age-related maculopathy, or persons with dizziness of vestibular origin.¹¹, ¹³, ¹⁴, ²⁸, ²⁹ This advice seems to be heeded by persons with rheumatoid arthritis³⁰ but not by those with vestibular deficits²⁹ or, according to this study, by those with chronic whiplash. This may reflect a lesser degree of handicap, or it may reflect that driving is an essential lifestyle activity that is difficult to avoid. Because driving is not curtailed despite difficulties with driving tasks such as reversing and reverse parking, methods of making driving easier for the whiplash population may need to be considered and evaluated. Simple vehicle modifications, as have been employed for people with ankylosing spondylitis or rheumatoid arthritis,³¹ such as additional mirrors, automatic transmission, or power steering, might be useful for persons with chronic whiplash.

The DHQ can be used to determine difficulty with driving.¹⁴ Nevertheless, the avoidance component of the modified DHQ in particular may prove to be a useful screening tool for patients with whiplash to identify specific components of driving difficulty. However, more research is necessary to investigate whether these self-reported driving difficulties relate to actual driving ability or safety in persons with whiplash. It is also unknown whether self-reported levels of driving difficulty or actually reduced driving ability relate to an increase in collision risk in this population.

Subjects in this study presented as a reasonably typical group of persons with chronic whiplash. On average, they had moderate levels of self-reported neck pain and disability,¹⁷, ¹⁹ marginally above threshold levels of psychologic distress (GHQ-28),¹⁷, ²⁰ and mild to moderate fear avoidance behaviors (TSK),¹⁹, ²² albeit nonremarkable levels of posttraumatic stress reactions (IES-R).¹⁷, ¹⁹, ²¹ In relation to the physical measures, the whiplash-associated disorder group demonstrated altered neck-influenced eye movement control (smooth pursuit neck torsion test) and decreased range of neck motion—physical measures shown to differentiate between chronic whiplash and control groups.⁵, ⁷

The analysis revealed moderate correlations (r=0.5) between the composite driving tasks score and reported levels of pain and disability (NDI), psychologic distress (GHQ-28), and posttraumatic stress reactions (IES-R), although there did not appear to be any relation between fear of movement (TSK) and difficulty driving. Previous research has also shown that fear of movement did not affect the development of movement dysfunction or lead to a poorer prognosis after whiplash injury.⁴, ¹⁷, ¹⁸ These results suggest that adequate pain management and specific psychologic strategies and/or support, especially with respect to anxiety while driving and posttraumatic stress, may be required for those with chronic whiplash-associated disorder who report driving difficulties. Such interventions may make driving tasks easier for those with chronic whiplash and could be a topic for future investigation.

Given that most subjects with whiplash reported most difficulty with reversing and reverse parking, it could be expected that this might be a result of decreased neck ROM or visual disturbances. However, there were no correlations between the physical measures of neck ROM and eye movement control (smooth pursuit neck torsion test) and the driving habits score or the degree of difficulty with reversing or reverse parking. Thus, our hypotheses of such associations were rejected. It is possible that decreased range of neck motion of any magnitude might impair reversing ability, in which case there might not be a strong correlation between the degree of difficulty in reversing and the magnitude of the loss of neck movement. Many subjects with whiplash reported that they now rely on mirrors more than before the accident and tend to turn their trunks rather than their heads when reversing. Research specifically looking at subjects with whiplash performing these tasks might be required before more definitive conclusions can be made about the influences of such physical features on driving.

Study Limitations 

This study has considered self-reports of driving habits only and not driving abilities and safety. Our findings of a lack of an association between reported driving difficulties and sensorimotor performance are counter to those of Gimse et al,¹⁵ who showed decreased reaction times and less steering precision in response to traffic sign recognition with chronic whiplash-associated disorder, with neck related deficits in eye follow as tested in the smooth pursuit neck torsion test. Our studies of physical performance were laboratory-based measures and not measures of performance in the context of driving. Thus, future studies measuring physical performance in the context of driving such as with a driving simulator may better determine any influence of physical performance on driving abilities.

Back to Article Outline

Conclusions 

Patients with chronic whiplash-associated disorder present with deficits in physical performance in tests of neck function as well as ongoing psychologic features and are likely to report difficulty with several driving tasks. This study revealed such reported driving difficulties are associated with ongoing psychologic distress and not with laboratory measures of sensorimotor performance of the cervical region. Further research is necessary to investigate physical and psychologic parameters in the context of driving and their effects on driving ability and safety.

Suppliers

Back to Article Outline

References 

1. Hoving JL, O'Leary EF, Niere KR, Green S, Buchbinder R. Validity of the neck disability index, Northwick Park neck pain questionnaire, and problem elicitation technique for measuring disability associated with whiplash-associated disorders. Pain. 2003;102:273–281
   • View In Article
   • Abstract
   • Full Text
   • Full-Text PDF (105 KB)
   • CrossRef
2. Mayou RA, Bryant BM. Effects of road traffic accidents on travel. Injury. 1994;25:457–460
   • View In Article
   • MEDLINE
   • CrossRef
3. Mayou R, Simkin S, Threlfall J. The effects of road traffic accidents on driving behaviour. Injury. 1991;22:365–368
   • View In Article
   • MEDLINE
   • CrossRef
4. Sterling M, Jull G, Vicenzino B, Kenardy J, Darnell R. Development of motor system dysfunction following whiplash injury. Pain. 2003;103:65–73
   • View In Article
   • Abstract
   • Full Text
   • Full-Text PDF (165 KB)
   • CrossRef
5. Dall'alba P, Sterling MM, Treleaven JM, Edwards SL, Jull GA. Cervical range of motion discriminates between asymptomatic persons and those with whiplash. Spine. 2001;26:2090–2094
   • View In Article
   • MEDLINE
   • CrossRef
6. Treleaven J, Jull G, LowChoy N. Smooth pursuit neck torsion test in whiplash associated disorders: relationship to self-reports of neck pain and disability, dizziness and anxiety. J Rehabil Med. 2005;37:219–223
   • View In Article
   • MEDLINE
7. Tjell C, Tenenbaum A. Smooth pursuit neck torsion test—a specific test for whiplash associated disorders?. J Whiplash Assoc Disord. 2003;1:9–24
   • View In Article
8. Treleaven J, Jull G, Sterling M. Dizziness and unsteadiness following whiplash injury: characteristic features and relationship with cervical joint position error. J Rehabil Med. 2003;34:1–8
   • View In Article
   • MEDLINE
   • CrossRef
9. Loudon JK, Ruhl M, Field E. Ability to reproduce head position after whiplash injury. Spine. 1997;22:865–868
   • View In Article
   • MEDLINE
   • CrossRef
10. Heikkila H, Astrom PG. Cervicocephalic kinesthetic sensibility in patients with whiplash injury. Scand J Rehabil Med. 1996;28:133–138
    • View In Article
    • MEDLINE
11. McGwin GJ, Chapman V, Owsley C. Visual risk factors for driving difficulty among older drivers. Accid Anal Prev. 2000;32:735–744
    • View In Article
    • MEDLINE
    • CrossRef
12. Holden W, Taylor S, Stevens H, Wordsworth P, Bowness P. Neck pain is a major clinical problem in ankylosing spondylitis, and impacts on driving and safety. Scand J Rheumatol. 2004;34:159–160
    • View In Article
    • MEDLINE
    • CrossRef
13. DeCarlo DK, Scilley K, Wells J, Owsley C. Driving habits and health-related quality of life in patients with age-related maculopathy. Optom Vis Sci. 2003;80:207–213
    • View In Article
    • MEDLINE
    • CrossRef
14. Owsley C, Stalvey B, Wells J, Sloane ME. Older drivers and cataract: driving habits and crash risk. J Gerontol A Biol Sci Med Sci. 1999;54:M203–M211
    • View In Article
    • MEDLINE
    • CrossRef
15. Gimse R, Bjorgen IA, Straume A. Driving skills after whiplash. Scand J Psychol. 1997;38:165–170
    • View In Article
    • MEDLINE
16. Rebbeck T, Sindhusake D, Cameron ID, et al. A prospective cohort study of health outcomes following whiplash associated disorders in an Australian population. Inj Prev. 2006;12:93–98
    • View In Article
    • MEDLINE
    • CrossRef
17. Sterling M, Jull G, Kenardy J. Physical and psychological factors maintain long-term predictive capacity post-whiplash injury. Pain. 2006;122:102–108
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (115 KB)
    • CrossRef
18. Sterling M, Jull G, Vicenzino B, Kenardy J, Darnell R. Physical and psychological factors predict outcome following whiplash injury. Pain. 2005;114:141–148
    • View In Article
    • Abstract
    • Full Text
    • Full-Text PDF (113 KB)
    • CrossRef
19. Vernon H, Mior S. The Neck Disability Index: a study of reliability and validity. J Manipulative Physiol Ther. 1991;14:409–415
    • View In Article
    • MEDLINE
20. Goldberg D. Manual of the General Health Questionnaire. Windsor: NFER-Nelson; 1978;
    • View In Article
21. Weiss D, Maramar C. The Impact of Event Scale Revised. In:  Wilson J,  Keane T editor. Assessing psychological trauma and PTSD. New York: Guilford; 1997;p. 399–411
    • View In Article
22. Kori S, Miller R, Todd D. Kinesiophobia: a new view of chronic pain behaviour. Pain Manag. 1990;1:35–43
    • View In Article
23. Revel M, Andre-Deshays C, Minguet M. Cervicocephalic kinesthetic sensibility in patients with cervical pain. Arch Phys Med Rehabil. 1991;72:288–291
    • View In Article
    • MEDLINE
24. Tjell C, Rosenhall U. Smooth pursuit neck torsion test: a specific test for cervical dizziness. Am J Otol. 1998;19:76–81
    • View In Article
    • MEDLINE
25. Treleaven J, Jull G, LowChoy N. The relationship of cervical joint position error to balance and eye movement disturbances in persistent whiplash. Manual Ther. 2006;11:99–106
    • View In Article
26. Crundall DE, Underwood G. Effects of experience and processing demands on visual information acquisition in drivers. Ergonomics. 1998;41:448–458
    • View In Article
    • CrossRef
27. Underwood G, Chapman P, Brocklehurst N, Underwood J, Crundall D. Visual attention while driving: sequences of eye fixations made by experienced and novice drivers. Ergonomics. 2003;46:629–646
    • View In Article
    • MEDLINE
    • CrossRef
28. Baldock M, Mathias J, McLean A, Berndt A. Self-regulation of driving and its relationship to driving ability among older adults. Accid Anal Prev. 2006;38:1038–1045
    • View In Article
    • MEDLINE
    • CrossRef
29. Cohen HS, Wells J, Kimball KT, Owsley C. Driving disability and dizziness. J Safety Res. 2003;34:361–369
    • View In Article
    • MEDLINE
    • CrossRef
30. Cranney AB, Harrison A, Ruhland L, et al. Driving problems in patients with rheumatoid arthritis. J Rheumatol. 2005;32:2337–2342
    • View In Article
    • MEDLINE
31. Busteed S, Daly M, Silke C, Molloy MG. Rheumatoid arthritis impairs driving ability even in patients with a low disability index. J Rheumatol. 2004;43:107–108
    • View In Article

• a Fastrak; Polhemus, 40 Hercules Dr, PO Box 560, Colchester, VT 05446.
• b Power Lab ENG Pod; ADInstruments Pty Ltd, Unit 13, 22 Lexington Dr, Bella Vista, NSW 2153, Australia.
• c Cleartrace; ConMed Corp, 525 French Rd, Utica, NY 13502.
• d Version 12; SPSS Inc, 233 S Wacker Dr, 11th Fl, Chicago, IL 60606.