Journal of the Neurological Sciences 252 (2007) 13 – 15 www.elsevier.com/locate/jns
Excessive daytime sleepiness and on-road driving performance in patients with Parkinson's disease M.M. Amick a,b,⁎, A. D'Abreu a,c , M.L. Moro-de-Casillas a,c , K.L. Chou a,c , B.R. Ott a,c a
b
Memorial Hospital of RI, Pawtucket, RI, United States Department of Psychiatry and Human Behavior, Brown Medical School, United States c Department of Clinical Neurosciences, Brown Medical School, United States
Received 6 July 2006; received in revised form 19 August 2006; accepted 22 September 2006 Available online 14 November 2006
Abstract The impact of excessive daytime sleepiness (EDS) on road test performance was examined in patients with Parkinson's disease (PD). Twenty-one patients with PD completed the Epworth Sleepiness Scale (ESS) and an on-road driving test. Five participants had EDS according to their self-report on the ESS. Neither EDS nor PD medications were associated with on-road driving performance. These findings suggest that in this pilot study EDS did not impair PD patients' driving skills on a formal driving evaluation. © 2006 Elsevier B.V. All rights reserved. Keywords: Parkinson's disease; Sleepiness; Driving; Dopamine agonist
1. Introduction Excessive daytime sleepiness (EDS) is commonly seen in patients with Parkinson's disease (PD) treated with dopamine agonist (DA) medications [1]. Frucht and colleagues first reported an association between sudden onset sleep or “sleep attacks” and car accidents in PD patients treated with a DA such as pramipexole or ropinirole [2]. A recent controlled study, however, found that sleepiness was not related to type of PD medication, rather patients treated with pramipexole, carbergoline, or levodopa monotherapy all endorsed similar amounts of sleepiness [3]. EDS in PD may instead be due to multiple factors including but not limited to medications, underlying sleep disorders (e.g. restless leg syndrome), and other causes of unrelated sleep disturbance (e.g. nocturia). Although the etiology of EDS is not clear, it is a common symptom in PD patients that significantly impacts performing important activities of daily living, such as driving. Be⁎ Corresponding author. Memorial Hospital of Rhode Island, Department of Medical Rehabilitation, 111 Brewster Street, Pawtucket, RI 02860, United States. Tel.: +1 401 729 2326; fax: +1 401 729 2243. E-mail address:
[email protected] (M.M. Amick). 0022-510X/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.jns.2006.09.020
tween 3.8 and 22.6% of patients with PD have reported falling asleep while behind the wheel of a car [1,4]. In a large survey study, elevated scores on the Epworth Sleepiness Scale (ESS), a brief, self-report measure of general sleepiness in adults, has been associated with PD patients falling asleep while driving [4,9]. Furthermore, an ESS score Nten predicted 77% of sleep episodes that occurred while PD patients were driving [9]. In a small sample of PD patients with EDS (all with ESS scores N10), three of the five patients demonstrated abnormal performance on a driving simulator task [5]. Although EDS in PD patients has retrospectively been associated with increased risk for motor vehicle accidents (MVAs), the impact of sleepiness during an actual road test has not been reported before this study. The primary objective of this study was to examine the relation between EDS and on-road driving performance in PD patients. Because EDS is a risk factor for MVAs, we hypothesized that PD patients with EDS would perform more poorly on a road test compared to PD patients without EDS. Since many of the participants in this study were taking a DA and EDS is a frequently reported side effect of DAs, the relation between driving performance and DA treatment was also examined.
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M.M. Amick et al. / Journal of the Neurological Sciences 252 (2007) 13–15
mous global rating of the participant's driving ability: “safe,” “marginal” or “unsafe.”
2. Methods 2.1. Participants
3. Results Twenty-one non-demented PD participants (14 men, 7 women) were consecutively recruited from the Movement Disorders Clinic at Memorial Hospital of Rhode Island. All participants gave written informed consent to participate in this study. Patients were diagnosed as having idiopathic PD by a movement disorders specialist based on the following criteria: presence of two out of three cardinal manifestations (tremor, bradykinesia, and rigidity) and a good response to dopaminergic medications. Participants were currently driving and had valid driver's licenses. Exclusion criteria included physical, ophthalmologic, or neurological disorders other than PD that might impair driving abilities. Patients with psychiatric disorders (mental retardation, schizophrenia, bipolar disorder, and substance abuse history within the past year) were excluded. Depression was allowed if it was controlled with medications but dosages were required to be stable for at least six weeks prior to study enrollment.
3.1. Statistical analyses In order to assess the impact of EDS and medication status on mean errors committed during the road test, independent samples t-tests were conducted. The influence of EDS and dopaminergic medications on global ratings of driving safety in PD patients were compared with Fisher's Exact Test, (FET). 3.1.1. Sleepiness Of the 21 patients, 5 (24%) had EDS (two males, three females). There was no difference between patients with or without EDS, with respect to gender, age, education, disease duration (years since diagnosis), levodopa equivalent dose, MMSE, H & Y score or UPDRS score. (see Table 1). 3.1.2. Sleepiness and driving On the driving evaluation, 14 patients were rated as safe, and seven received marginal ratings. Two of the five patients (40%) with EDS and five of the 16 patients (31%) without EDS received a marginal rating on the road test. There was no difference between PD patients with or without EDS in these global ratings of driving safety (p = 0.56, FET) or total road tests scores (t = .11, ns). Road tests scores are shown in Fig. 1.
2.2. Clinical evaluation Demographic variables included age, education, mental status (MMSE), and gender. Medications were converted into levodopa equivalent doses [6]. All patients were evaluated with the Hoehn and Yahr (H & Y) scale, motor section of United Parkinson's Disease Rating Scale (UPDRS), and the ESS within two weeks of the on-road driving test. EDS was defined as a score of N 10 on the ESS [9].
3.1.3. DA and driving Thirteen participants were treated with a DA (7 DA alone, 6 DA plus carbidopa/levodopa), and all five of the patients who met criteria for EDS were in this group. Participants were treated with either pramipexole (n = 7), ropinirole (n = 3), or pergolide (n = 3). Of the eight remaining subjects, all but two were treated with carbidopa/levodopa. Those patients receiving DA had higher ESS scores (t = 2.83, p = 0.01). Patients treated with a DA had a mean ESS score of 8.6 (SD = 4.0), whereas patients not treated with a DA had a mean ESS score of 4.3 (SD = 2.2). Four of the 13 patients treated with DA and three of the eight patients not treated
2.3. Road test All participants were administered an on-road driving test by a professional driving instructor during daylight hours under good conditions. The driving test was based on the Washington University Road Test (WURT), a standardized driving measure that has established reliability [7]. The WURT was adapted for use on comparable streets in Rhode Island [8]. Based on the instructor's rating for safe completion of each driving maneuver, a total score ranged from zero (best) to 108 (worst). The instructor also made a trichoto-
Table 1 Characteristics of PD patients with and without EDS
Age Education Disease duration (years) UPDRS H & Y score Medication dose Levodopa equivalent (mg) MMSE ESS
PDs with EDS (n = 5) Mean SD
PDs without EDS (n = 16) Mean SD
t-value
p-value
63.4 15.6 3.2 25.8 Range (2–3) 417.4 29.0 12.4
69.6 14.3 7.0 n = 13 29.2 Range (2–3) 446.6 27.8 5.3
1.5 1.0 1.0 0.9 (χ2) = 0.40 0.2 1.5 5.5
0.16 0.32 0.32 0.40 0.53 0.9 0.2 b0.001
12.7 2.6 0.8 6.3 184.4 0.7 2.1
6.6 2.4 8.1 8.0 325.3 1.7 2.7
M.M. Amick et al. / Journal of the Neurological Sciences 252 (2007) 13–15
Fig. 1. PD patients with EDS (EDS+) committed a similar number of errors on the road test compared to PD patients without EDS (EDS−). Error bars represent the standard error of the mean.
with DA received marginal ratings on the road test. There was no relationship of DA to global ratings (p = .57, FET) or total road test scores (t = .22, ns). 4. Discussion To our knowledge, this is the first study to examine the relation between self reported EDS and performance on a formal on-road driving evaluation. We found no significant association between EDS (as measured with the ESS) and global ratings of driving safety or total road test scores. Furthermore, although all patients with EDS in our study were being treated with a DA, there was no association between treatment with a DA and performance on the driving evaluation. The limitations of our study should be kept in mind when interpreting our results. First of all, we had no objective measures of sleepiness, and chose to use only the ESS to measure daytime sleepiness. While there are a variety of subjective scales for measuring sleepiness in PD, the ESS was selected for this study because it is the most frequently used measure in the PD and driving literature (e.g. [1,4,9]). Furthermore it can be quickly and easily administered, which makes it an ideal tool for use in the daily care of PD patients. Another limitation was our small sample size. Nevertheless, we believe that our findings are relevant in terms of designing future studies, as well as in preventing further accidents in PD patients with EDS. In our sample of PD patients, EDS was a common phenomenon with 24% of participants receiving scores of N 10 on the ESS. This number, however, is somewhat smaller than previous reports from larger survey studies of the prevalence of EDS in PD patients (approximately 50%) [1,4]. Small sample, differences in criteria for EDS, as well as sample demographics might account for the variability between our study and previous reports. Unlike survey studies, we could not include PD patients at the later stages of the disease as we only recruited actively driving participants. Consistent with the results of other studies, however, was our finding that EDS and scores on the ESS were related to treatment with DA medications [1,10]. While not significant, there was a higher percentage of patients with EDS (40%) who received marginal ratings on
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the road test compared to PD patients without EDS (31%). Overall, our PD group endorsed less EDS than previous studies and it may be that not enough PD patients with EDS were included in this study. However, the mean road test scores were very similar in PD patients with and without EDS. We suspect that the presence of the driving instructor may have functioned to keep PD drivers more alert, as participants were aware that falling asleep could cause them to fail the road test. A future study with a larger sample of PD drivers with EDS will be necessary to confirm these initial findings. In our study, PD patients who suffer from EDS performed similarly on formal on-road driving evaluations to PD patients without EDS. While actual on-road performance of PD patients with and without EDS is necessary to explore the relationship between sleepiness and driving, a formal evaluation with a driving instructor may not be the best method. Future studies perhaps using video recording during daily driving, may be helpful in further examining the relation of sleepiness to driving skills. However, to improve driving safety, PD patients who suffer from EDS should be encouraged to drive with a companion to ensure an appropriate level of alertness and driving skills. References [1] Ondo WG, Dat Vuong K, Khan H, Atassi F, Kwak C, Jankovic J. Daytime sleepiness and other sleep disorders in Parkinson's disease. Neurology 2001;57:1392–6. [2] Frucht S, Rogers JD, Greene PE, Gordon MF, Fahn S. Falling asleep at the wheel: motor vehicle mishaps in persons taking pramipexole and ropinirole. Neurology 1999;52:1908–10. [3] Pal S, Bhattacharya KF, Agapito C, Chaudhuri KR. A study of excessive daytime sleepiness and its clinical significance in three groups of Parkinson's disease patients taking pramipexole, cabergoline, and levodopa mono and combination therapy. J Neural Transm 2001;108:71–7. [4] Hobson DE, Lang AE, Martin WR, Razmy A, Rivest J, Fleming J. Excessive daytime sleepiness and sudden-onset sleep in Parkinson disease: a survey by the Canadian Movement Disorders Group. JAMA 2002;287:455–63. [5] Moller JC, Stiasny K, Hargutt V, Cassel W, Tietze H, Peter JH, et al. Evaluation of sleep and driving performance in six patients with Parkinson's disease reporting sudden onset of sleep under dopaminergic medication: a pilot study. Mov Disord 2002;17:474–81. [6] Herzog J, Volkmann J, Kopper F, Potter M, Lorenz D, Steinbach M, et al. Two-year follow-up of subthalamic deep brain stimulation in Parkinson's disease. Mov Disord 2003;18:1332–7. [7] Hunt LA, Murphy CF, Carr D, Duchek JM, Buckles V, Morris JC. Reliability of the Washington University Road Test. A performancebased assessment for drivers with dementia of the Alzheimer type. Arch Neurol 1997;54:707–12. [8] Brown LB, Ott BR, Papandonatos GD, Sui Y, Ready RE, Morris JC. Prediction of on-road driving performance in patients with early Alzheimer's disease. J Am Geriatr Soc 2005;53:94–8. [9] Meindorfner C, Korner Y, Moller JC, Stiansy-Kolster K, Oertel WH, Kruger H. Driving in Parkinson's disease: mobility, accidents, and sudden onset of sleep at the wheel. Mov Disord 2005;20:832–42. [10] Paus S, Brecht HM, Koster J, Seeger G, Klockgether T, Wullner U. Sleep attacks, daytime sleepiness, and dopamine agonists in Parkinson's disease. Mov Disord 2003;18:659–67.
