Results

DRIVERS BEFORE INJURY AND AT INTERVIEW

Most people (381(67.7%)) were drivers before injury. One hundred and thirty people (23.1%) were not drivers before injury, and no relevant information was available for 52 (9.2%).

Of the 381 previous drivers, 139 (36.5%) were driving at interview and 242 (63.5%) were not. Of the previous drivers only 41 (10.8%) reported receiving a formal driving ban from the DVLA due to their injury. Twenty seven (66%) of these was because of risk of seizures. A further 20 previous drivers (5.3%) reported being advised not to drive by a clinician, giving a total of 61 patients who had been specifically advised not to drive.

PROBLEMS REPORTED AT INTERVIEW RELATED TO DRIVING

The problems reported by patients and family members which were likely to be associated with driving performance (such as wakefulness, behavioural problems, attentional problems, sensory deficits, and memory problems), were examined for those currently driving, previous drivers not currently driving, and banned and non-banned drivers (table1).

CURRENT DRIVERS

Almost half (67 (48.2%)) of those driving reported behavioural problems such as irritability, anger management, and aggression. Eighty nine (64%) reported memory problems. Problems which may impair wakefulness and alertness during driving were also often reported—that is, tiredness (50 (36%)) and sleep disturbances (42 (30.2%)). Problems with concentration and attention were reported by 39 (28.1%), giddy spells or dizziness by 41 (29.5%), and problems with balance and coordination by 18 (12.9%). Emotional problems were also reported: 31 patients (22.3%) reported depression, and carers reported that the patients displayed personality changes (20 (14.4%)) and lack of insight (13 (9.4%)).

EX-DRIVERS

Table 1 also shows the number of previous drivers who had not returned to driving reporting these problems. Most problem items were reported as often by ex-drivers as by current drivers. The χ² test of association was used to compare the two groups of drivers for each problem item. There were significant differences between the two groups for epilepsy (p=0001), driving (p=004), community mobility (p=0.038), and vision (p=0.048) with ex-drivers reporting these problems more often than current drivers. “Other behavioural problems”, which included temper and abusive behaviour, were also reported significantly more often by ex-drivers (p=0.002). Aural problems were reported more often by ex-drivers than current drivers but this not reach significance at the 5% level (p=0.085). Diminished alcohol tolerance was reported by more current drivers than ex-drivers, but the difference was not significant at the 5% level (p=0.08).

BANNED DRIVERS

Only 61 out of 381 previous drivers reported that they had been formally advised not to drive. Two of these drivers admitted driving despite their licence being revoked, and three said that they continued to drive although formally advised not to by clinicians. The “banned drivers” reported most problem items as often as current drivers. Exceptions were a higher incidence of epilepsy (27 (44.3%)), mood swings (16 (26.2%)), problems with driving (48 78.7%)), and lack of insight reported by their carers (10 (16.4%)). The χ²test of association was used to compare banned drivers (n=61) with non-banned drivers (n=320) for each problem item. The frequency of reported problems was only significantly different between the two groups for four items: epilepsy (p=0001), driving (p=0001), mood swings (p=0.05), and sleep problems (p=0.05).

FIM+FAM SCORES ON DRIVING RELATED ITEMS

Scores on the FIM+FAM were used as a more objective measure of driving related problems to corroborate the problems reported by patients and their families. The four items attention, orientation, emotional status, and safety judgement were chosen to assess those skills required by drivers. These items were defined using the FIM+FAM scoring decision tree19 and shown in table 2.

Table 3 shows the scores on the four FIM+FAM items for the whole study group (n=538), current drivers (n=132), ex-drivers (n=231), banned drivers (n=58), and all non-banned drivers (n=305). The FIM+FAM is scored from 1 to 7 where 1 is fully dependent on others and 7 is fully independent. A score of 6 indicates some problems, and 5 or less indicates that a patient requires help or is unable to perform the task.

For all four FIM+FAM items a score of 7 was achieved by a higher proportion of current drivers than both ex-drivers and the interview group as a whole. The means (SD) on the four items were (a) for current drivers: attention 6.3 (SD 1.01), orientation 6.8 (SD 0.75), emotion 5.6 (SD 1.57), and safety 6.6 (SD 0.85); (b) for ex-drivers all mean scores were about one level lower: attention 5.3 (SD 1.86), orientation 5.9 (SD 1.91), emotion 4.7 (SD 1.93), and safety 5.3 (SD 2.0). For banned versus non-banned drivers the means (SD) were (a) for banned ex-drivers: attention 5.7 (SD 1.5), orientation 6.5 (SD 1.16), emotion 4.95 (SD 1.76), and safety 5.9 (SD 1.51), only slightly lower than those of the current drivers; (b) for all non-banned drivers mean scores were attention 5.7 (SD 1.71), orientation 6.2 (SD 1.71), emotion 5.0 (SD 1.87), and safety 5.8 (SD1.82).

A recent study analysing the properties of the FIM+FAM concluded that raw ratings may be justifiably treated as good approximations to points on interval scales of measurement.20 Consequently the χ² test of association was used to compare the FIM+FAM scores of the group of previous drivers who had returned to driving with the group of previous drivers who had not returned to driving. There was a significant difference between the two groups: p=0.0001 for attention, orientation, and safety judgement, and p=0.002 for emotion.

The χ² test of association was also used to compare banned drivers with non-banned drivers for each FIM+FAM item. Surprisingly there was no significant difference between banned and non-banned drivers on any of the four items.

SEVERITY OF INJURY AND RETURN TO DRIVING

The severity of traumatic brain injury was classified as mild, moderate, severe, and very severe.17 Cross tabulations using the χ² test of association were calculated to compare the injury severity of the drivers with the ex-drivers, and the banned drivers with the non-banned drivers. There was a significant difference in injury severity between the drivers and the ex-drivers (p=0.001). Overall, the driving group had less severe head injuries than the ex-driving group, in particular, 31 (22.3%) current drivers had received a mild head injury, compared with only 19 (8.0%) of ex-drivers (table 4). There was no significant difference between the injury severity of the banned drivers and the non-banned drivers (p=0.68). Although most of the banned drivers (40 (65.6%)) had had a severe or very severe head injury, four (6.6%) had sustained a mild head injury.

Discussion

Many of those patients who had returned to driving after traumatic brain injury reported problems which could significantly affect their ability to drive. Importantly, the proportion of patients reporting these problems was very similar for both the driving and ex-driving groups. Visual problems and problems with concentration and attention were reported by over a quarter of those who were driving. Half the drivers reported behavioural problems such as a “short fuse”, uncontrolled aggression, and irritability. Other emotional problems such as depression and mood swings were not reported any less often by the drivers than the ex-drivers. For the subgroup of formally banned drivers there was a higher incidence of epilepsy and mood swings than was found among non-banned drivers.

Family members of the driving group reported personality change and lack of insight in the patient as often as family members of the ex-driving group. These two factors have been identified10as being particularly important in increasing risk and reducing driving skills because psychological deficits are less likely than physical deficits to be identified and compensated for. Although most of those people who had returned to driving were physically competent to drive a vehicle, it may be argued that some were putting themselves and others at risk due to their psychological, emotional, and cognitive problems.

As a group, the patients who had returned to driving had received a less severe traumatic brain injury than those who had not yet returned to driving. This finding is likely to be influenced by the short follow up period, when those who had had mild injuries were most likely to have returned to driving. Nevertheless, over half (56.2%) of the current drivers had received a severe, or very severe head injury.

On the FIM+FAM drivers achieved significantly higher scores than ex-drivers, indicating that clinicians thought them to be more independent. This finding is consistent with that found by others.21 However, there were no significant differences between banned and non-banned drivers. This may be because risk of epilepsy was the main reason for a driving ban rather than other deficits.

The four items chosen to be particularly relevant to driving performance are all FAM items, which have been found to demonstrate lower interrater reliability than FIM items.18 However, recent research suggests that both FIM and FAM items have a highly acceptable level of internal consistency and reliability.20 The FIM+FAM has, however, been shown to have ceiling effects when used with patients after traumatic brain injury, which causes the measure to be relatively insensitive to changes, and may mask the incidence of higher level cognitive and emotional deficits.22

MEDICAL FITNESS TO DRIVE: ADVICE TO PATIENTS

Holders of a British driving licence are advised to inform the Driver and Vehicle Licensing Agency (DVLA) “At once if you have any disability (includes any physical or mental condition) which affects (or may future affect) your fitness as a driver if you expect it to last more than three months”.

The freely available MCAP guides advise medical practitioners that responsibility for determining the fitness to drive of an individual person rests with the DVLA; however, doctors should advise the patient to inform the DVLA of any condition which may affect the patient's fitness to drive.12 23 Only in exceptional circumstances should a doctor breach patient confidentiality and inform the DVLA himself. Responsibility for informing the licensing authorities is also problematic in other countries. In a survey carried out in the United States the different states have different requirements for impaired drivers: 15 states authorise physicians to report impaired drivers, of which seven require physicians to report them, and in thirty five states drivers are required to report themselves.24

Visual deficits were reported by about one third of previous drivers (current drivers 28.1%; ex-drivers 37.6%) of whom few reported that they had received specific visual examinations or advice about driving. Special considerations are required when assessing whether a person with brain injury is visually fit to drive, and close liaison should be maintained between the optometrist and other head injury professionals involved in the patient's care.25 Many of our interviewees reported that they were unable to judge distances, were dazzled by oncoming cars, and found it difficult to see well enough to drive at night, factors also noted by others.26 27

From our interviews it seems that few patients were told that the DVLA should be informed, or were given any formal advice, particularly if they had made a good physical recovery and there was a delay before referral to the rehabilitation team. Rehabilitation professionals were often concerned to find that a patient had returned to driving despite problems with vision, coordination, anger, and uncontrolled aggression. Attempts to stop the patient driving were thwarted by the fact that “the doctor told me I could”.

For those patients who have epilepsy diagnosed, the regulations are fairly straightforward,28 but are much less so for other disorders associated with head injury. We were told that general practitioners had given patients a green light to drive without the benefit of any formal assessment, but sometimes with advice to keep initial journeys short. One patient reported that his general practitioner had advised him against informing the DVLA, suggesting that it would be very difficult to get his licence back.

An example of conflicting advice was a patient who had a moderate head injury at the age of 43. He was a self employed long distance lorry driver. At the interview he reported double vision, memory problems, severe headaches, and fatigue. At his outpatient appointment the neurosurgeon informed him that he could return to work, apparently without realising that the patient worked as a driver of a heavy goods vehicle. His case manager, concerned for the patient's safety managed to get this decision reversed. This action left the patient confused, and he reported to us that although his treatment had been good, it had “worked against me”. He had received “a letter from the doctor saying it is absolutely fine to go back to work”; then had the decision overturned. His subsequent inability to work caused the family severe financial hardship. He reported that he wished he had not gone to rehabilitation and withdrew from therapy shortly afterwards, leaving the area without a forwarding address.

At the time of the interviews none of the study sites seemed to have a formal policy about giving advice and information on return to driving; however, during the course of the 5 year study this issue came to be considered more systematically by five of the sites. The National Head Injuries Association (Headway) produce a leaflet advising patients on return to driving,29 yet few of the patients we interviewed were aware of this information. In practice, the decision to resume driving was often made by the patient himself, a finding consistent with that made by Priddy et al 30 who also noted that patients were willing to restrict their driving activities to suit their altered abilities. From our interviews we found that patients, and particularly their families, showed good common sense in delaying a return to driving and then resuming gradually, starting with short and familiar journeys, often accompanied. Some patients took refresher driving lessons of their own volition.

DRIVING ASSESSMENTS

Four of the study sites had close access to specialist disabled driving centres which were able to provide a formal assessment of the person's suitability to return to driving. Study patients who seemed to have few problems were often offered a “fast track” assessment which ensured that the patient was competent to drive on the road. However, such assessments do not generally assess the higher cognitive levels required in driving as noted by van Zomerenet al.31 Study patients who had a formal driving assessment and were passed as fit to drive reported that this increased their confidence and improved their quality of life. Being able to drive again often meant that they could resume previous activities. Those unable to resume driving often reported frustration with their situation, and felt trapped in their homes.

POSSIBLE LIMITATIONS OF THE RESEARCH

This research project was not an epidemiologically based study. However, the project presented an opportunity to study a large group of patients selected to receive rehabilitation by centres of good practice whose resources were enhanced by Department of Health grants specifically for head injury rehabilitation, and thus expected to receive a better service than could be offered by units without the benefit of a dedicated head injury team. Despite this, it seemed that driving advice was often not routinely given to previous drivers, or if it was, then the patients themselves did not recall it, which is of equal concern.

UNANSWERED QUESTIONS AND FUTURE RESEARCH

This paper reports interview responses mostly made during the early months after injury when patients had not long returned to driving. A long term follow up of these patients is crucial to ascertain whether a head injury predisposes drivers to further accidents.

Conclusions

Few patients reported that doctors had advised them not to drive after their traumatic brain injury. Risk of epilepsy was the most likely reason for a formal driving ban. Patients who had returned to driving reported a similar pattern of deficits as those who had not returned to driving, the main difference between the two groups being a higher level of functional independence among the current drivers. Patients were not given clear nor consistent advice about return to driving and often had to rely on informal advice from therapists, on their common sense, or that of their family. It is recommended that patients are informed of their entitlement to drive after a head injury by the rehabilitation team and their general practitioner. However, such advice can be unpopular with patients, and not necessarily followed. For patients who do meet the current medical standards of fitness to drive careful assessment and monitoring can lead to a safe return to driving and a consequent improvement of their quality of life.