A Longitudinal Study Examining Self-Regulation Practices in Older Drivers with and without Suspected Mild Cognitive Impairment

Mild cognitive impairment can impact driving performance and self-regulation practices. However, there is little evidence on how cognitive impairment may impact these self-regulation practices over a period of time. Therefore, the aim of this study was to examine changes in the number and type of situations in which older drivers with and without suspected mild cognitive impairment (MCI) self-regulate their driving over a one-year period, after accounting for relevant confounders. A longitudinal cohort study involving older drivers (65+ years) from metropolitan Western Australia was interviewed by a telephone interview at baseline and one-year follow-up. The Telephone Cognitive Screen (T-CogS) was also administered to determine changes in their cognitive status. The outcome of interest was the number and type of situations older drivers self-regulated their driving. A total of 670 drivers were interviewed at baseline (suspected MCI: n = 227; no cognitive impairment: n = 443) and one-year follow-up (suspected MCI: n = 251; no cognitive impairment: n = 419), which provided 1340 observations. Drivers with suspected MCI increased the number of driving situations in which they self-regulated by 13% over a period of one-year compared with drivers without cognitive impairment (IRR = 1.13, 95% CI = 1.02-1.27, p = 0.025). Specifically, drivers with suspected MCI had 60% increased odds of self-regulating when "making turns across oncoming traffic" compared with drivers without cognitive impairment (unadjusted OR = 1.60, 95% CI = 1.02-2.53, p = 0.041). Other significant factors included being female (IRR = 1.87, 95% = 1.52-2.32, p = 0.001), aged 75+ years (IRR = 1.33, 95% CI = 1.10-1.60, p = 0.003), higher number of comorbidities (1-3 comorbidities: IRR = 1.26, 95% CI = 1.01-1.58, p = 0.040; 4+ comorbidities: IRR = 1.39, 95% CI = 1.08-1.78, p = 0.011), "decreased driving confidence" (IRR = 1.32, 95% CI = 1.10-1.58, p-value = 0.003) and "preference of having someone else drive" (IRR = 1.38, 95% CI = 1.12-1.70, p = 0.003). Having one or more traffic infringements was also associated with a decrease in the number of self-regulated driving situations (IRR = 0.80, 95% CI = 0.67-0.95, p = 0.011). Over a one-year period, drivers with suspected MCI increased the number of situations in which they self-regulated their driving compared with drivers without cognitive impairment, particularly when "making turns across oncoming traffic". Future studies should examine whether this