Cognitive Reserve (CR) developed from observation that several individuals show fewer cognitive impairment compared to others with the same brain injuries or neuropathology. Cognitive reserve is a potentially modifiable characteristic. Most of studies on cognitive reserve were conducted on chronic progressive diseases such as dementia. This study aims to define the role of cognitive reserve in geriatric delirium cases.

This case-control study was conducted in the acute geriatric inpatient of Cipto Mangunkusumo Hospital, Jakarta, Indonesia on June to September 2019 that consisted of 33 subjects with delirium and 33 controls. The measurement of cognitive reserve was done using the Indonesian adaptation of Cognitive Reserve Index questionnaire (CRIq) with 3 subscales, i.e. Education, Work Activity and Leisure Time.

We found that the CRIq scores of delirium patients were lower compared to the non-delirium controls both on total and each subscores, with a statistically significant mean difference (p<0,01). Patients with low-medium cognitive reserve also more likely to develop delirium compared to those with medium-high cognitive reserve (OR 9; 95% CI 2.86 to 28.22).

Low cognitive reserve may serve as a risk factor for delirium in the elderly. The measure of CRI in the geriatric inpatients unit can be used to determine those at risk of developing delirium. Further research are warranted to elaborate potentially modifiable variables of cognitive reserve to minimize the risk of delirium.