Self-Regulation and Executive Functioning as Related to Survival in Motor Neuron Disease: Preliminary Findings.

OBJECTIVE: Disease progression varies widely among patients with motor neuron disease (MND). Patients with MND and coexisting dementia have shorter survival. However, implications of mild cognitive and behavioral difficulties are unclear. The present study examined the relative contribution of executive functioning and self-regulation difficulties on survival over a 6-year period among patients with MND, who scored largely within normal limits on cognitive and behavioral indices.
METHODS: Patients with MND (N = 37, age = 59.97 ± 11.57, 46% female) completed the Wisconsin Card Sorting Task as an executive functioning perseveration index. The Behavior Rating Inventory of Executive Functions (BRIEF-A) was used as a behavioral measure of self-regulation in two subdomains self-regulatory behavior (Behavioral Regulation) and self-regulatory problem-solving (Metacognition). Cox proportional hazard regression analyses were used.
RESULTS: In total, 23 patients died during follow-up. In Cox proportional hazard regressions adjusted for a priori covariates, each 10-point t-score increment in patient-reported BRIEF-A self-regulatory behavior and problem-solving difficulties increased mortality risk by 94% and 103%, respectively (adjusted HR = 1.94, 95% CI = 1.07-3.52; adjusted HR = 2.03, 95% CI = 1.19-3.48). In sensitivity analyses, patient-reported self-regulatory problem-solving remained significant independent of disease severity and a priori covariates (adjusted HR = 1.68, 95% CI = 1.01-2.78), though the predictive value of self-regulatory behavior was attenuated in adjusted models (HR = 1.67, 95% CI = 0.85-3.27). Caregiver-reported BRIEF-A ratings of patients and Wisconsin Card Sorting Task perseverative errors did not significantly predict survival.
CONCLUSIONS: Preliminary evidence suggests patient-reported self-regulatory problem-solving difficulties indicate poorer prognosis in MND. Further research is needed to uncover mechanisms that negatively impact patient survival.