Ⅰ. Introduction
Driving is a complicated high-level performance that requ ires motor control abilities including muscular strength, coor dination, range of motion, and cognitive abilities including attention and judgment (Anstey et al., 2005). Additionally, driving is an important activity that enhances independent move, social interaction, and integration in the local commu nity and improves people’s satisfaction by helping out the occupational activity, shopping, and social participation in t heir daily activities (Johnston et al., 2005; Lane & Benoit, 2011).
In the case of patients with central nervous system disord ers like stroke, their diseases influence driving performance abilities including motor control, cognition, and perception t hat causes driving cessation (Akinwuntan et al., 2002; Mars hall et al., 2007). Driving performance of stroke patients re quires cognitive abilities, such as attention, reaction time, vi sual attention, thinking ability, and environmental perception during driving. Particularly, their cognitive abilities are one of the most important factors to draw their driving performa nce behavior (Akinwuntan et al., 2012). Due to disorders of cognitive abilities, stroke patients can experience driving ce ssation (Marshall et al., 2007).
The damage of cognitive functions is a disability that mo st stroke patients have, and about 25 % of patients who hav e had a stroke for over 3 months show a serious level. Parti al damage to cognitive functions appears on 50~75 % of pa tients (Desmond et al., 2000). The damage cognitive functio n is one of the factors that increase the ratio of traffic accid ent risk and has a bad influence on driving (Rizzo et al., 20 01). More so, overall driving performance ability is evaluate d using activities of daily living (ADL) and instrumental act ivities of daily living scales, which can judge whether peopl e are eligible to drive through comprehensive driving evalua tion (Dickerson et al., 2014).
Stroke patients’ cognitive function relating to driving abil ity can be analyzed with a clock drawing test (CDT), which is known to evaluate a patient’s driving performance in the way of checking his or her space perception ability and he mineglect during their driving (Manning et al., 2014). Freun d (2005) reported that the CDT based scale is a reliable an d useful evaluation tool to identify subjects who need the e valuation for driving rehabilitation. Furthermore, Shulman (2000) reported that CDT is needed for driving rehabilitatio n because it presents cognitive factors appropriately in the course of evaluating clock drawing.
MBI used in evaluating ADL is a useful tool to evaluate a stroke patient’s basic activity level (Shah et al., 1989). Th e MBI provides a therapist with information on a stroke pat ient’s general functions, thus, it’s an appropriate evaluation tool to determine a suitable moment for the patient’s drivin g rehabilitation despite that it’s not a tool to measure a parti cular driving skill (Akinwuntan et al., 2006). According to Park’s research (2017), the MBI score is a useful evaluation tool to predict a recommended time of driving rehabilitation for stroke patients.
As such, evaluating cognitive abilities including visual pe rception and ADL for driving performance is very importan t in predicting and determining whether a stroke patient can drive. Nevertheless, there is not much research on the analy sis of correlations between cognitive functions, ADL, and d riving performance with the use of MBI and CDT. Therefor e, this study tries to analyze the correlations between stroke patients’ cognitive abilities, ADL, and driving performance.
Ⅱ. Methods
1. Subjects
Subjects of the study were patients admitted to the rehabilitation hospital B and hospital J, both situated in Seoul, Korea, which gave their consent to participate fully in the study. This study was deliberated and approved by the institutional review board of Soonchunhyang University (SCH-IRB), and the criteria for inclusion in the trial and general features of subjects are as follows (Table 1).
1) A patient diagnosed with a stroke by a neurologist or a physiatrist
2) A patient that experienced a stroke at least 6 months ago
3) A patient with driving experience of 1 year or longer
4) A patient with a mini-mental status examination–Korea (MMSE-K) score of 20 or above and understood the trial and was capable of executing the trial
Table 1. General demographic characteristics of participants
MMSE-K; mini mental status examination–Korea, MBI; modified barthel index
2. Procedures
One examiner had a 1:1 interview. Before the interview, the researcher practiced several times to fully understand the procedure and to have an effective interview. The researcher fully explained the purpose and method of the study to the subjects and thus, obtained their consent. The researcher conducted the CDT and MBI to evaluate the subject's cognitive function and ADL ability. The subjects who completed all the tests took the Eca faros-driving simulator test for evaluating its driving performance.
3. Instrumentation
1) Clock drawing test
A CDT is a tool for evaluating the cognitive function (Shulman, 2000). In this study, the production task-based clock drawing method, developed by Yim (2010) was used. The subject was instructed verbally by the evaluator not to show the model of the watch and asked to draw an analog watch under one condition. Free drawing conditions were used for the CDT and the 15-point rating method suggested by Freedman et al. (1994) was used for the rating system. Inter-tester reliability (ICC = 2.1) of CDT showed .75 (p<.01) and the correlation coefficient between the MMSE-K and the CDT showed r = .77 (p<.01) (Lee et al., 2011).
2) Modified Barthel index
MBI is a tool for evaluating the degree of independence of patients with stroke and was developed by Shah (1989). It consists of 10 kinds of specific daily activities, each of which gives five levels of scores, with a total of 100 points. The level of dependence based on the sum of the MBI scores is 0~24 points for total dependence, 25~49 points for severe dependence, 50~74 points for mild dependence, and 91~99 points for minimal dependence. Inter-rater reliability was showed .90~.98 (Jung et al., 2007).
3) Eca faros-driving stimulator
The virtual reality driving simulator used in this study is the ultra-car system developed by Eca faros-driving simulator (Fig 1). In this study, items of the driving simulator program were reconstructed based on the test items and scorecard of the actual road driving test of Korea to raise its validity. The test items of the road driving test presented in Appendix 26 of the Enforcement Rules of the Road Traffic Act include 12 scoring items (check before departure, driver's posture, start, acceleration and speed maintenance, braking, steering, car body sensing, transit discrimination, course change, driving straight and left, right turn, parking, etc.). In this study, the intermediate course (practice driving and evaluation) was selected from the driving simulator programs that can evaluate 12 evaluation items. The scoring was made with 12 items including the check before departure, driver's posture, start, acceleration and speed maintenance, braking, steering, car body sensing, transit discrimination, course change, driving straight and left, right turn, parking, and others, based on 100 points, and when the score is 70 or above, it was considered to be pass and fail for any less.
Fig 1. Eca faros-driving simulator
4. Statistical analysis
The results were analyzed using the windows SPSS 24.0 statistical program. To verify statistical significance, the significance level was set to .05. Descriptive statistical analysis was used to present the general information of the subjects, and Spearman's correlation analysis was used to examine how the relationship between the subjects' cognitive function, ADL ability, and driving performance would affect their driving performance. Additionally, to see if the cognitive function and ADL ability could be used to assess driving performance, Wilks’s Lambda test was conducted.
Ⅲ. Results
1. Correlation between cognitive function, ADL ability and driving performance
The correlation between the measured cognitive function, ADL ability of the subjects, and their driving performance, CDT was -.777 (p<.01), and MBI was –.022 (Table 2).
Table 2. Correlation between cognitive function, ADL ability and driving performance
*p<.01, CDT; clock drawing test, MBI; modified Barthel index, DS (P&F); driving simulator (pass & fail)
2. Discriminant analysis of cognitive function, ADL and driving Performance
Wilks’s Lambda test was performed on stroke patients for the discriminant analysis of cognitive function, ADL ability, and driving performance. The cognitive function showed that the sensitivity (100.0 %) and specificity (40.0 %) for the CDT were found to be significant, but the ADL ability showed that the sensitivity (62.5 %) and specificity (40.0 %) for the MBI were not found to be significant (Table 3).
Table 3. Discriminant analysis of cognitive function, ADL and driving performance
CDT; clock drawing test, MBI; modified Barthel index
Ⅳ. Discussion
This study examined and evaluated the relationship betwe en cognitive function, ADL ability, and driving performance of stroke patients.
First, as for the correlation between cognitive function an d driving performance, CDT was -.777 (p<.01) and statistic ally significant, but the correlation was not found in MBI (-.022, p=932). Such results were consistent with the evalua tion tools shown to have the highest correlations in the prev ious studies on the prediction of driving performance (Mann ing et al., 2014). These results indicated that cognitive funct ion is an important factor in driving performance, and it is also an evaluation tool that can be used to predict the drivi ng performance of stroke patients.
The fact that MBI did not show a significant result, may indicate that the participants of this study have low MBI sc ores, and especially, those with 50~74 MBI scores seem to have an influence on statistical significance. In the research that analyzed the driving performance ability of stroke patie nts in Korea using a driving simulator and MBI, the cut-off MBI score was over 86.5 in the driving simulator (Park, 20 17). Regarding the MBI scores of the participants of this st udy, the number of those with over 86.5 was 5, and the nu mber of those with under 86.5 was 13. Those who passed the driving simulator evaluation were four participants who have over 86.5 MBI scores. This is a similar result to previ ous studies. To compensate this, it seemed necessary to anal yze additionally based on MBI cut-off score 86.5.
In the analysis of the results of cognitive function evaluat ion tools and results of the driving simulator test (pass/fail) to discriminate between and examine CDT and driving perf ormance, the result was found to be significant except for MBI. As per the CDT, it was seen to have a sensitivity of 100.0 %, a specificity of 40.0 %, and an accuracy of 67.7 %, and this supports the study of Freund et al. (2005). The CDT was verified effective as a driving performance evalua tion through previous overseas studies, but there is no study on domestic stroke patients using the CDT. Additionally, th e previous studies on the elderly’s driving performance abili ty with the use of the CDT mostly analyzed the correlation between the frequency of annual traffic accidents and the equency of traffic violations, but there were not enough stu dies on the driving simulator (Diegelman et al., 2004; Freun d et al., 2005). Therefore, this study is important because it verifies the clinical usefulness of the CDT by confirming th at CDT is a suitable tool in evaluating domestic stroke patie nts’ driving performance ability. Also, the CDT is a useful tool to determine the driving performance of stroke patients. The CDT could be used to screen people not suitable for ac tual road driving while evaluating their driving performance for the field of driving rehabilitation.
This study has some limitations. The number of participa nts is small, and the analysis of stroke is not done on each part of the body, so it is difficult to generalize the result. If the evaluation tool was a visual perception tool such as DTVP-A, the visual perception ability like hemineglect coul d be researched more accurately. This study confirmed the importance of cognitive function on driving performance of stroke patients and also found that the CDT, cognitive funct ion evaluation tool, were useful in the prediction of driving performance. Finally, the results of this study are useful in deducing the possibility of actual road driving of stroke pati ents willing to resume their driving privileges.
Ⅴ. Conclusion
This study aimed at evaluating the correlation between co gnitive function, ADL ability, and driving performance in st roke patients. The conclusions as per this study are as follo ws. First, the driving skills of stroke hemiplegic patients we re shown to be associated with the CDT evaluation tool. Se cond, the driving skills of stroke hemiplegic patients were found to be highly related to CDT. Since the results of the cognitive function evaluation tool were shown to be signific ant in evaluating the driving performance of stroke patients, cognitive function has proven to be highly related to drivin g performance. Also, it was shown that cognitive function was highly correlated to the CDT, in turn, making it a suita ble tool for evaluating a patient’s driving performance. Fina lly, this study can confirm the cognitive elements needed fo r driving in the situation that stroke patients’ driving rehabil itation is considered important, and is expected to become a useful resource for various driving evaluations and driving rehabilitation relating to cognitive functions.
References
- Akinwuntan AE, Feys H, De Weerdt W, et al(2002). Determinants of driving after stroke. Arch Phys Med Rehabil, 83(3), 334-341. https://doi.org/10.1053/apmr.2002.29662.
- Akinwuntan AE, Feys H, De Weerdt W, et al(2006). Prediction of driving after stroke: A prospective study. Neurorehabil Neural Repair, 20(3), 417-423. https://doi.org/10.1177/1545968306287157.
- Akinwuntan AE, Wachtel J, Rosen PN(2012). Driving simulation for evaluation and rehabilitation of driving after stroke. J Stroke Cerebrovasc Dis, 21(6), 478-486. https://doi.org/10.1016/j.jstrokecerebrovasdis.2010.12.001.
- Anstey KJ, Wood J, Lord S, et al(2005). Cognitive, sensory and physical factors enabling driving safety in older adults. Clin Psychol Rev, 25(1), 45-65. https://doi.org/10.1016/j.cpr.2004.07.008.
- Desmond DW, Moroney JT, Paik MC, et al(2000). Frequency and clinical determinants of dementia after ischemic stroke. Neurology, 54(5), 1124-1131. https://doi.org/10.1212/WNL.54.5.1124.
- Dickerson AE, Meuel DB, Ridenour CD, et al(2014). Assessment tools predicting fitness to drive in older adults: A systematic review. Am J Occup Ther, 68(6), 670-680. https://doi.org/10.5014/ajot.2014.011833.
- Diegelman NM, Gilbertson AD, Moore JL, et al(2004). Validity of the clock drawing test in predicting reports of driving problems in the elderly. BMC Geriatr, 4, Printed Online. https://doi.org/10.1186/1471-2318-4-10.
- Freedman M, Leach L, Kaplan E, et al(1994). Clock drawing: A neuropsychological analysis. New York, Oxford University Press, pp.44-78.
- Freund B, Gravenstein S, Ferris R, et al(2005). Drawing clocks and driving cars. J Gen Intern Med, 20(3), 240-244. https://doi.org/10.1111/j.1525-1497.2005.40069.x.
- Johnston MV, Goverover Y, Dijkers M(2005). Community activities and individual satisfaction with them: Quality of life in the first year after traumatic brain injury. Arch Phys Med Rehabil, 86(4), 735-745. https://doi.org/10.1016/j.apmr.2004.10.031.
- Jung HY, Park BK, Shin HS, et al(2007). Development of the Korean version of modified Barthel index: multi-center study for subjects with stroke. J Korean Acad Rehabil Med, 31(3), 283-297.
- Lane AK, Benoit D(2011). Driving, brain injury and assistive technology. NeuroRehabilitation, 28(3), 221-229. https://doi.org/10.3233/NRE-2011-0651.
- Lee SH, Lee SA, Park SY(2011). The reliability and validity of clock drawing test. J Korean Soc Occup Ther, 19(4), 107-115.
- Manning KJ, Davis JD, Papndonatos GD, et al(2014). Clock drawing as a screen for impaired driving in aging and dementia: is it worth the time?. Arch Clin Neuropsychol, 29(1), 1-6. https://doi.org/10.1093/arclin/act088.
- Marshall SC, Molnar F, Man-Son-Hing M, et al(2007). Predictors of driving ability following stroke: A systematic review. Top Stroke Rehabil, 14(1), 98-114. https://doi.org/10.1310/tsr1401-98.
- Park MO(2017). Clinical usefulness on K-MBI for decision of driving rehabilitation period in patients with stroke: A pilot study. Journal of Rehabilitation Welfare Engineering & Assistive Technology, 11(2), 91-98. https://doi.org/10.21288/resko.2017.11.2.91.
- Rizzo M, McGehee DV, Dawson JD, et al(2001). Simulated car crashes at intersections in drivers with Alzheimer's disease. Alzheimer Dis Assoc Disord, 15(1), 10-20. https://doi.org/10.1097/00002093-200101000-00002
- Shah S, Vanclay F, Cooper B(1989). Improving the sensitivity of the Barthel index for stroke rehabilitation. J Clin Epidemiol, 42(8), 703-709. https://doi.org/10.1016/0895-4356(89)90065-6.
- Shulman KI(2000). Clock-drawing: is it the ideal cognitive screening test. Int J Geriatr Psychiatry, 15(6), 548-561. https://doi.org/10.1002/1099-1166(200006)15:6<548::aidgps242>3.0.co;2-u.
- Yim SK(2010). A comparison of the clock drawing test between positive schizophrenics and negative schizophrenics. Graduate school of Chonnam National University, Republic of Korea, Master's thesis.