Falls, mood, and driving safety in multiple sclerosis

Abstract

Mobility difficulties are a progressive and burdensome consequence of multiple sclerosis (MS) with pervasive effects on functioning. As such, driving retains a critical role in maintaining mobility and functional autonomy in people with MS (pwMS). While cognitive and physical deficits have been established as risk factors for unsafe driving outcomes (e.g., motor vehicle accidents (MVAs) and traffic violations) in pwMS, little is known about the role of falls and psychological symptoms in such outcomes. This study also sought to examine the relationship between falls, psychological symptoms, and self-reported driving characteristics such as MS symptoms interfering with driving ability and restrictive driving practices. Participants included 114 patients at a tertiary care MS Center who had been previously diagnosed with MS by a neurologist. Closed-ended questions about the occurrence of falls within the last year, perceptions about MS symptoms interfering with driving ability, and driving restrictions were presented to all participants; depressive and anxiety symptoms were evaluated by the Patient Health Questionnaire-9 (PHQ-9) and the Hospital Anxiety and Depression Scale – Anxiety subscale (HADS-A), respectively. Driving records were also obtained from the Department of Motor Vehicles (DMV), which noted all traffic violations and MVAs received within the last five years. Results showed that participants without a history of falls had 2.3 times more MVAs within the last five years; however, for traffic violations, MS symptoms hindering driving ability, and driving restrictions, there were no differences between fallers and non-fallers. A higher number of traffic violations received were associated with higher depressive (Wald c2 (1) = 17.46, p < 0.001) and anxiety (Wald c2 (1) = 21.67, p < 0.001) symptoms. When adjusting for demographic and disease-related factors, depressive and anxiety symptoms were also associated with the number of symptoms interfering with driving ability (depression: b= 0.39, SE = 0.04; anxiety: b = 0.33, SE = 0.04) and the number of driving restrictions (depression: b= 0.35, SE = 0.04; anxiety: b = 0.20, SE = 0.05). Moreover, there was an interaction effect of age on fall status in relation to violations (Wald c2 (1) = 5.86, p = 0.015), indicating that older drivers without a history of falls had received a higher number of traffic violations within the last five years. No other significant interaction effects between age and psychological symptoms in relation to DMV outcomes were observed. Exploratory analyses also indicated that more severe fatigue was associated with a higher number of MS symptoms interfering with driving behavior (r = 0.43, p < 0.001) and a higher number of driving restrictions (r = 0.35, p < 0.001). A higher number of symptoms hindering driving were also associated with lower extraversion (r = -0.24, p = 0.009) and higher agreeableness (r = 0.23, p = 0.016). This is the first study to investigate the relationship between falls, psychological symptoms, driving outcomes, and self-reported driving characteristics in pwMS. Our findings demonstrate a strong association between fall status and MVAs. Psychological symptoms were also strongly associated with traffic violations, MS symptoms impacting driving ability, and driving restrictions. As fall status and psychological symptoms are related to negative driving outcomes, such factors can enhance the identification of pwMS at risk for unsafe driving and, therefore, allow for earlier intervention.