[Impairment of Odor Recognition in Myotonic Dystrophy Type 1]

There is evidence that impaired human cognitive abilities are reflected in loss of olfactory abilities. Declining olfactory perception may be a biomarker for impairment of cognitive function and of impending illnesses in neurodegenerative disorders such as Parkinson's disease (PD) and Alzheimer's disease (AD). Previously, we reported that patients with myotonic dystrophy type 1 (DM 1) had lower sensitivity to emotional facial expressions as well as abnormal olfactory threshold or recognition level. In DM 1, pathological studies have reported neurofibrillary tangles in several temporal areas including the entorhinal cortex (ENT), hippocampus (HI), and the amygdala. We observed that patients with DM 1 showed signal abnormalities in the olfactory limbic areas on magnetic resonance imaging. Our findings underscore the need to pay careful attention to significant decreases in odor identification abilities caused by diverse forms of abnormal brain function, especially in the AMG, ENT and HI.