Tourette Syndrome and Driving

Abstract

Background

Driving ability may be impaired in patients with various movement disorders, but it has not been studied in patients with Tourette syndrome (TS).

Cases

We describe a series of 6 patients from our large cohort of TS patients followed in our movement disorders clinic in whom severe tics have had interfered with their driving abilities. The motor tics involved facial muscles and caused visual impairment because of frequent blinking and transient blepharospasm (dystonic tic), but complex limb and truncal tics also seriously impacted their driving.

Conclusions

Although majority of patients with TS have no functional impairment, severe motor tics in some patients may adversely affect their driving ability, potentially causing danger to themselves and others. Screening for such troublesome tics should be considered in patients with TS, particularly in teenagers who are being evaluated for driver's licensing.

Driving is one of the most critical skills required by our society for mobility and productivity. Most individuals start driving as soon as it is permitted by law, and although they are able to obtain their license, their driving abilities may be impaired as a result of physical or mental conditions. Driving is a complex activity that requires fully coordinated body movements in conjunction with appropriate motor activation, proprioception, and vision, along with higher integrative functions such as selective and divided attention, visuospatial interpretation, visual‐motor integration, and decision making. ¹ There have been many reports of the impact of various, mostly parkinsonian, movement disorders on driving performance as a result of decreased reaction time, reduced ability to respond to perceived visual cues, tremors, and other motor abnormalities. ² , ³ , ⁴ , ⁵ , ⁶ , ⁷ , ⁸ , ⁹ , ¹⁰ , ¹¹ Multiple motor, cognitive and visual limitations, coupled with excessive daytime sleepiness or attention deficit disorders, account for majority of the reported conditions that impair driving abilities in patients with movement disorders, but hyperkinetic disorders such as tremors, dystonia, tics, chorea, and myoclonus have not been specifically addressed in studies of driving and movement disorders. Specifically, the effects of Tourette syndrome (TS) on driving have not been yet studied except in 1 recent study. ¹² In this survey of 228 adults with TS, 183 (87.7%) of whom had a driver's license, 9% reported that it was difficult to pass the driving test because their tics interfered with driving. In the current case series, we aim to draw attention to the possibility that tics and other TS‐related symptoms may interfere with driving and to characterize driving impairment in patients with TS.

Case Series

We recently identified 6 patients (4 males and 2 females) with TS, mean age 22 (Table 1), from the Movement Disorders Clinic at Baylor College of Medicine in whom driving was affected by TS as defined by the Diagnostic and Statistical Manual of Mental Disorders Fifth edition (DSM‐5). ¹³ These patients were included in this report because their tics have been interfering with their ability to drive. Their behavioral comorbidities, such as attention deficit hyperactive disorder (ADHD) and obsessive–compulsive disorder (OCD) were also evaluated, but no formal driving rating scales were used. The patients were videotaped according to a standard video protocol after an appropriate consent form was signed.

TABLE 1.

Case series of patients with TS‐related impaired driving

Case	Age/sex	Tics	Impairment in driving	Other	Comorbid	Treatment
1	17/F	Neck extensions (whiplash tics), shoulder shrugging, abdominal patting, back tensing and arching, head beating, snorting, throat clearing, right foot inversion	Urge to tense up her back and turn the wheel abruptly pulling her vehicle off the road	Concussion because of head banging tics and chronic back pain	OCD, ADHD	Prior medications: guanfacine, clonidine, topiramate, and zonisamide. Currently enrolled in ecopipam trial
2	21/M	Frequent eye blinks, right neck flexion, right hand touching forehead, head nodding movements, popping sounds, ankle popping, nail biting, grunting and throat clearing	Excessive eye blinks as well as an ankle popping movement during driving. These tics, although troublesome, were actually less intense during driving because of the perceived need to concentrate on driving	None	None	Prior medications: fluoxetine, aripiprazole, buspirone, haloperidol, and paroxetine. Currently enrolled in a pimavanserin trial
3	17/F	Stereotyped eye rolling, facial grimacing, jerk‐like neck flexion‐extension, quick bilateral wrist flexion, and foot inversion movements	Premonitory urge/restlessness preceding eye‐rolling interfered with keeping eyes on road	Tension headaches related to neck tics	OCD, ADHD	Tetrabenazine
4	22/M	Involuntary movements of hands and legs, neck flexion, back tensing, squealing noises or words, and coprolalia	Truck driver, whole body complex tics affected driving, had a collision	Tics interfere with sleep at night	OCD, ADHD	Deutetrabenazine
5	31/M	Eye rolling and blinking for several seconds, transient blepharospasm, teeth chipping	Unable to drive because of intermittent blepharospasm	Easily distracted during conversation	OCD	Botulinum toxin injections
6	23/M	Shoulder rolling, facial twitch, blocking tics, eye blinking, oculogyric tics, neck stretching, eversion of right foot, sniffing, humming, and coprolalia	Unable to drive because of oculogyric tics and foot eversion	Misses days from work	OCD	Tetrabenazine

Illustrative Cases

Case 1

The first case is a 17‐year‐old right‐handed student who initially experienced involuntary movements as a toddler manifested by shrugging her shoulders or patting her stomach with her hands. She subsequently developed severe tics including, but not limited to, facial tics, foot inversion, chirping sounds, and loud phonic tics such as snorting and throat clearing. Some of her tics were associated with self‐injurious behaviors such as hitting her head or face against the wall or with her hands, and repetitive, forceful neck extensions (“whiplash tic”). She once suffered a brain concussion as a consequence of her head‐hitting tics. She also experienced repetitive back tensing and arching, associated with chronic neck and back pain. The tics were typically preceded by an intense urge characterized by a need to tense up her back and turn the wheel abruptly pulling her vehicle off the road on several occasions. Although this could be also interpreted as an expression of underlying impulsivity, her description suggests that it represents a premonitory urge because the dangerous maneuver worsens when she tries to control her tics while driving (Video 1 ). She and her parents expressed serious concerns that these tics could interfere with her driving. She does report some obsessive–compulsive tendencies, like counting fan rotations, arranging items to make sure they are even, or going back and re‐touching certain items till they feel correct. She was previously diagnosed with ADHD.

Video 1.

Case 1 (Table 1) showing motor tics, including a description of tic‐related impairment of driving.

Case 2

The second case is a 21‐year‐old man who first noted abnormal sounds (grunting and throat clearing) and movements during his childhood years. Since age 15, these phonic tics progressively worsened and became associated with excessive eye blinks, repetitive neck flexion to the right, and touching his forehead with the right hand. The excessive blinking and intermittent blepharospasm, a form of a dystonic tic, resulted in impaired vision and, when coupled with involuntary head nodding movement and “ankle popping”, began to interfere with his driving ability. He has never been in a motor vehicle accident but was stopped by law enforcement once for speeding. He describes a premonitory urge, feeling anxious and unable to concentrate, as well as tightness in the chest before the motor tics interfere with driving. He also has constant thoughts of contamination by chemicals and ruminates about how chemicals might lead to decreased brain function and cause his brain to be less competent.

Discussion

The primary aim of this report is to draw attention to impaired driving in patients with TS as a result of their motor tics, often complicated by certain comorbidities such as attention deficit and obsessive–compulsive behavior. In our series, patients with TS acknowledged that their driving performance was impaired or compromised as a result of intermittent blepharospasm, a form of dystonic facial tic, eye rolling tics, shoulder rotatory movements, neck extensions (“whiplash tics”), leg movements, and other tics, as well as distractions by concentrating on controlling premonitory sensations and urges (Table 1). All these patients have experienced impairment in their driving because of tics, but case 2 reports that his baseline severe tics actually slightly improved during driving because of his need to concentrate on the driving activity (Table 1).

Prior reports have focused on impaired attention as the primary reason for interference with ability to drive and resulting motor vehicle accidents in patients with TS. This, coupled with impulse control disorder and other behavioral comorbidities, may increase the risk of having encounters with law enforcement among patients with TS. ¹⁴ One study concluded that patients with TS or chronic tic disorders are more likely to be convicted of driving under the influence. ¹⁵ More importantly, increased awareness that tics and ADHD can impair driving should lead to preventive measures designed to assure safety for TS patients and others.

Driving is a complex activity that requires normal visual–auditory–sensory motor coordination. Using functional magnetic resonance imaging (MRI) Calhoun et al ¹ found decreased activity in the anterior cingulate cortex and in fronto‐parietal regions and increased activity in cerebellar and occipital areas during driving. One model exemplified driving as a continuous information‐processing activity, which the driver integrates sensory input to execute fine motor movements that induce further circumstances perceived and processed again by the driver who executes a new task. ¹⁶ Other models considered driving as a risk compensation behavior, which drivers adjust their driving (eg, speed) to establish a balance between what happens on the road and their level of acceptable subjective risk. ¹⁶

With the evident requirement that driving activity requires coordinated movements during vehicle maneuvering, it is obvious that any alteration of movement, such as present in hypokinetic or hyperkinetic movement disorder, may adversely affect driving ability. Many studies have found that the presence of Parkinson's disease (PD) poses safety concerns in comparison to healthy controls when it comes to driving. ³ , ⁴ , ⁶ , ⁹ , ¹⁰ , ¹¹ PD patients may suffer from motor and cognitive dysfunction both of which might contribute to driving impairment. PD patients have been found to have late deceleration times, ⁸ slow reflex reaction time, ⁷ and delayed ability to respond to road signs and red lights. ³ In addition to impairment in rapid sequential and coordinated movements, PD patients may experience daytime sleepiness further complicating their ability to drive safely. ² , ¹⁷ Although hyperkinetic movement disorders are expected to interrupt normal coordinated activity required for driving, this has not been fully evaluated by well‐designed studies. In Huntington's disease (HD), for example, impaired driving has been attributed to cognitive impairment and visual incoordination rather than chorea. ¹⁸ One study raised the possibility that postural sway and slower cognitive processing predicted abnormal driving performance, ¹⁹ but limb chorea has not been described to intervene with the driving ability in patients with HD. In 1 study, increased reaction time was thought to be the culprit in impaired driving in patients with HD. ²⁰ As expected, blepharospasm has been noted to impact driving abilities. In 1 study, 26 of 66 (39.4%) patient with blepharospasm were involved in motorcycle (n = 21) or car (n = 5) accidents. ²¹ The other hyperkinetic movement disorder, which driving was assessed was cervical dystonia (CD), but no serious safety concerns were noted in a small study in which 10 patients were compared to healthy controls with the use of a simulator. ²² This is in contrast to our own experience with a large number of patients with CD, many of whom raise concerns about their driving because of head tremor, limitation of neck range of motion, and neck pain, although most experience improvement in these symptoms with local botulinum toxin injections. ²³

There is remarkable paucity of information about driving in patients with TS. In one case report of a 42‐year‐old truck driver with TS, beneficial effects on psychomotor functions related to driving performance was attributed to the use of Δ⁹ ‐tetrahydrocannabinol (THC). ²⁴ This is paradoxical, because THC has been reported to impair driving performance in a study of 26 healthy volunteers in the Netherlands. ²⁵ One of our patients expressed fear of driving after viewing on YouTube a patient with TS learning how to drive. ²⁶ One study of 3449 individuals with TS in the Swedish National Patient Register found a 50% increase in risk for transport accidents in patients with TS compared to general population, but this was mostly attributed to comorbid ADHD rather than to tics. ²⁷ Indeed, when individuals with ADHD were excluded there was no statistically significant difference between patients with TS and healthy controls. Another study noted that whereas only 3.2% of motor vehicle accidents were linked to tics, majority of TS patients reported that their tics caused them to have trouble obtaining driver's licenses. ¹² Although this has not been formally addressed in our case series or any epidemiological study, based on our long‐term experience with thousands of patients with TS evaluated in our clinic over the past 4 decades, <1% of our patients have reported driving impairment.

TS is a neurodevelopmental disorder manifested by motor and phonic tics as well as a variety of behavioral comorbidities, particularly ADHD, OCD, and impulse control disorders. ²⁸ Although many neurotransmitters have been implicated in the pathophysiology of tics, dysfunction of the inhibitory γ‐aminobutyric acid‐ergic (GABA) system leading to a state of “disinhibition” has been proposed to play a key role. ²⁹ Furthermore, structural and functional MRI studies have suggested that the insula plays an important role in premonitory urges and generation of tics. ³⁰ , ³¹ It is not known how the increased connectivity between the insula and the sensorimotor cortex are involved in the pathophysiology of tics and premonitory urges and whether it adversely impacts normal coordination and motor function required for driving. ³⁰ It is likely that properly selected and applied individualized comprehensive behavioral intervention for tics (CBIT) and habit reversal training (HRT), coupled with pharmacologic treatment, botulinum toxin and even deep brain stimulation (DBS) enables patients with TS to control their tics for safe driving. ³² Further studies are needed to clarify whether treatment provides functional improvement in patients with driving impairment.

In addition to tics, most patients with TS also have a variety of behavioral comorbidities (particularly ADHD) that may affect their driving abilities. ¹⁵ Studies have shown that drivers with ADHD, in addition to inattention glitches while driving, often exhibit inappropriate anger that may escalate into a road rage, therefore, increasing the risk of unsafe driving and higher rates of car crashes compared to a healthy population. ¹⁴ , ¹⁵ , ³³ , ³⁴ However, surprisingly, patients with ADHD were found to perform better at a hazardous situation than healthy controls in 1 study, a finding proposed to be related to the better engagement of the patient in the task at hand with a heightened task demand, but medicated drivers clearly performed better in terms of speed control and fewer driving errors than those with untreated ADHD. ³⁵ Although the Swedish National Patient Register study ²⁷ concluded that ADHD is the main factor in driving impairment among patients with TS, impulsivity, as illustrated in our patient in case 1, may also play a role. Indeed, impulsivity might affect driving ability not only in patients with TS, but also other movement disorders including PD. ³⁶

We propose the application of tic questionnaires, such as the one used by Fernández de la Cruz et al ¹² or by others. ³⁷ , ³⁸ , ³⁹ Although in most patients with TS tics do not interfere with their functionality, if there are concerns about patients’ driving abilities they should be referred to professional service companies, credentialed by the Association for Driver Rehabilitation Specialists, that can assess their driving abilities in a real‐world or simulated environments. Patients who are identified to have serious interference with driving should be advised to stop driving until their tics, ADHD, or other TS‐related symptoms are brought under adequate control.

Conclusion

Driving is a complex mental and motor activity that requires coordinated movements and skills to safely operate a vehicle. Although the effects of numerous medical and neurological conditions on driving have been studied, there is paucity of data on how TS affects driving performance. In addition to motor tics, patients with TS often have behavioral comorbidities, such as ADHD, that may interfere with their abilities to drive effectively and safely. The present cases, selected from our large cohort of TS patients, draw attention to a potential public health concern because TS might impact driving leading to collisions or other motor vehicle mishaps in certain cases. Although tics usually do not impair driving, in certain cases with severe TS, driving performance should be evaluated and the TS‐related symptoms should be appropriately addressed to prevent self‐harm or injury to others.

Author Roles

1) Research project: A. Conception, B. Organization, and C. Execution.

K.M.: 1B, 1C

J.J.: 1A, 1B

Disclosures

Ethical Compliance Statement: The authors confirm that they have read the Journal's position on issues involved in ethical publication and affirm that this work is consistent with those guidelines. The approval of an institutional review board was not required for this work. All patients signed an informed consent.

Funding Sources and Conflict of Interest: The authors report no sources of funding and no conflicts of interest relevant to this work. The authors declare that there are no additional disclosures to report.

Financial Disclosures for the Previous 12 months: Dr. Makhoul does not report any financial disclosures in the previous 12 months. Dr. Jankovichas received research or training grants from AbbVie Inc; Acadia Pharmaceuticals; Cerevel Therapeutics; CHDI Foundation; Dystonia Coalition; Emalex Biosciences, Inc; F. Hoffmann‐La Roche Ltd; Huntington Study Group; Medtronic Neuromodulation; Merz Pharmaceuticals; Michael J Fox Foundation forParkinson Research; National Institutes of Health; Neuraly, Inc.; Neurocrine Biosciences; Parkinson's Foundation; Parkinson Study Group; Prilenia Therapeutics; Revance Therapeutics, Inc; Teva Pharmaceutical Industries Ltd. Dr. Jankovic has served as a consultant for Aeon BioPharma; Allergan, Inc; Revance Therapeutics; Teva Pharmaceutical Industries Ltd. Dr. Jankovic hasreceived royalties from Cambridge; Elsevier; Medlink: Neurology; Lippincott Williams and Wilkins; UpToDate; Wiley‐Blackwell.