Objectives:
According to theoretical interpretations of the olfactory training effects, the training may indirectly exert positive influence on cognitive functioning in patients with dementia of Alzheimer’s type. The mechanism of action is stimulation of an increased regional cerebral blood flow in areas of brain, which are shared by olfactory and memory processes. The aim of this paper is to verify the hypothesis that olfactory training improves cognitive functioning of MCI patients.

Methods:
Cross-over assignment was used as the intervention method. Participants diagnosed with MCI (N=35; 17 male and 18 female) constituted their own control group. During the first 12 weeks from the baseline evaluation no therapeutic actions were performed. The subjects underwent neuropsychological assessments and entered in the second stage of the study. In that stage they were subjected to a daily olfactory training, which included two few minutes long sessions per day, which were performed for the following 3 months. Subject’s cognitive functioning was measured at three time points: at the baseline, after 3 months and after 6 months. The scales employed in the study to measure memory were: ACE-III, CVLT and MMSE.

Results:
Statistically significant improvement in memory functions measured with CVLT, MMSE, ACE-III Memory and ACE-III Total Score were obtained. They are considered artefacts related to practice effects, not true training results. Apart from that trends suggesting improvements on ACE-III Attention were noted as well.

Conclusions:
The authors review theoretical implications of the completed study. Methodological challenges pertaining to the study design are discussed and future research directions are proposed.