Shepard, Paul W.

Abstract Study Objectives To analyze cognitive deficits leading to unsafe driving in patients with REM Sleep Behavior Disorder (RBD), strongly associated with cognitive impairment and synucleinopathy-related neurodegeneration. Methods Twenty isolated RBD (iRBD), 10 symptomatic RBD (sRBD), and 20 age- and education-matched controls participated in a prospective case-control driving simulation study. Group mean differences were compared with correlations between cognitive and driving safety measures. Results iRBD and sRBD patients were more cognitively impaired than controls in global neurocognitive functioning, processing speeds, visuospatial attention, and distractibility (p < .05). sRBD patients drove slower with more collisions than iRBD patients and controls (p < .05), required more warnings, and had greater difficulty following and matching speed of a lead car during simulated car-following tasks (p < .05). Driving safety measures were similar between iRBD patients and controls. Slower psychomotor speed correlated with more off-road accidents (r = 0.65) while processing speed (−0.88), executive function (−0.90), and visuospatial impairment (0.74) correlated with safety warnings in sRBD patients. Slower stimulus recognition was associated with more signal-light (0.64) and stop-sign (0.56) infractions in iRBD patients. Conclusions iRBD and sRBD patients have greater selective cognitive impairments than controls, particularly visuospatial abilities and processing speed. sRBD patients exhibited unsafe driving behaviors, associated with processing speed, visuospatial awareness, and attentional impairments. Our results suggest that iRBD patients have similar driving-simulator performance as healthy controls but that driving capabilities regress as RBD progresses to symptomatic RBD with overt signs of cognitive, autonomic, and motor impairment. Longitudinal studies with serial driving simulator evaluations and objective on-road driving performance are needed.

SummaryObjectiveWe aimed to determine the frequency of probable obstructive sleep apnea (pOSA) in refractory epilepsy monitoring unit inpatients and clinical features associated with pOSA, including risk for sudden unexpected death in epilepsy (SUDEP).MethodsWe prospectively recruited 49 consecutive adult patients admitted to the Mayo Clinic Epilepsy Monitoring Unit with focal, generalized, or unclassified epilepsy syndromes. pOSA was identified using oximetric oxyhemoglobin desaturation index (ODI) and the Sleep Apnea–Sleep Disorders Questionnaire (SA‐SDQ) and STOP‐BAG screening tools. Revised SUDEP Risk Inventory (rSUDEP‐7) scores were calculated, and epilepsy patients with and without pOSA were compared with Wilcoxon signed‐rank tests. Correlation and regression analyses were utilized to determine relationships between pOSA and rSUDEP‐7 scores.ResultsThirty‐five percent of patients had pOSA, with a mean ODI of 11.3 ± 5.1/h (range = 5.1‐22.8). Patients with pOSA were older and heavier, and more frequently had a focal epilepsy syndrome and longer epilepsy duration, with higher SA‐SDQ and STOP‐BAG scores (all P < 0.05). Median rSUDEP‐7 score was 3 ± 1.4 (range = 0‐6). Higher rSUDEP‐7 scores were positively correlated with higher ODI (P = 0.036). rSUDEP‐7 score ≥ 5 was associated with pOSA by ODI, SA‐SDQ, and STOP‐BAG questionnaire criteria (P < 0.05).SignificanceOur pilot study identified a high frequency of pOSA in refractory epilepsy monitoring patients, finding that pOSA patients were older and heavier, with higher screening symptoms for sleep apnea and more frequent focal seizures with a longer epilepsy duration. We also found a possible association between OSA and SUDEP risk. Identification and treatment of OSA in patients with epilepsy could conceivably provide a novel approach toward preventing the risk of SUDEP. Future studies with polysomnography are needed to confirm predictive features for OSA in epilepsy populations, and to determine whether OSA is associated with SUDEP risk.