Use of the Montreal Cognitive Assessment test to investigate the prevalence of mild cognitive impairment in the elderly elective surgical population.

Postoperative cognitive disorders are common in elderly patients. Pre-existing cognitive impairment including mild cognitive impairment may be an important risk factor for developing postoperative cognitive dysfunction and may not be detected in a standard preoperative interview, yet is not routinely sought. Our primary aim was to estimate the prevalence of mild cognitive impairment among elderly patients presenting to our hospital for elective surgery using a simple established screening tool: the Montreal Cognitive Assessment test. Secondarily, we wished to determine the proportion of patients with mild cognitive impairment who presented with this information available, the effect of increasing age on the prevalence of mild cognitive impairment and whether the timing and location of testing influenced results. We used the Montreal Cognitive Assessment test to screen preoperative patients aged 65 years and over. Our results suggested a potential prevalence of mild cognitive impairment of 56%, with prevalence increasing with age. No patients in the sample had a recorded diagnosis of mild cognitive impairment. Testing in either the preadmission clinic or on admission on the day of surgery yielded similar results. We found the Montreal Cognitive Assessment test to be a simple screening tool that was easily administered during the pre-admission visit.