Sniffing out dementia

Characteristics of initial symptoms and symptoms at diagnosis in probable dementia with Lewy body disease: incidence of symptoms and gender differences

AIM

Although dementia with Lewy bodies (DLB) is characterized by a variety of initial symptoms, there are almost no reports of the initial symptoms of DLB assessed in a large number of cases. We retrospectively evaluated the initial symptoms of 234 participants with DLB and DLB-related symptoms at diagnosis and characterized any gender differences in the symptom profiles.

METHODS

This study consisted of 234 participants with probable DLB who met the diagnostic criteria outlined in the Fourth Consensus Report of the DLB Consortium (2017). DLB was confirmed based on several characteristic biomarkers for dopamine transporter imaging with ¹²³ I-N-omega-fluoropropyl-2-beta-carbomethoxy-3-beta (4-iodophenyl) nortropane single-photon emission computed tomography, ¹²³ I-metaiodobenzylguanidine myocardial scintigraphy, and brain perfusion measured with single photon emission computed tomography. In addition, core and supportive clinical features were considered in the diagnosis.

RESULTS

Initial symptoms included cognitive impairment (41.9%) and psychiatric symptoms (i.e. visual and auditory hallucinations, delusions, and depression) (42.3%). Almost half of the women initially presented with psychiatric symptoms, with significantly more women than men presenting with auditory hallucinations. In contrast, men had a significantly higher rate of rapid eye movement sleep behaviour disorder (RBD) than women did. At diagnosis, DLB-related symptoms differed between men and women, with male patients exhibiting significantly more RBD, parkinsonism, hyposmia, and syncope than female patients. Moreover women presented significantly more often with auditory hallucinations than did men.

CONCLUSIONS

Our results indicate that there are gender differences in the initial symptoms of DLB, as well as in the presentation of subsequent symptoms observed at diagnosis. There was a higher incidence of RBD in men, whereas women had a higher incidence of psychotic symptoms.

[Severe olfactory dysfunction is a predictor of dementia with Parkinson's disease]

Recently, we identified that hyposmia, one of the most typical non-motor features in Parkinson's disease (PD), was a predictive feature of PDD (Parkinson's disease dementia). The multivariate logistic analysis identified severe hyposmia and visuoperceptual impairment as independent risk factors for subsequent dementia within 3 years. The patients with severe hyposmia had an 18.7-fold increase in their risk of dementia for each 1 SD (2.8) decrease in the score of odor stick identification test for Japanese (OSIT-J). We also found an association between severe hyposmia and a characteristic distribution of cerebral metabolic decline, which was identical to the findings observed in PDD. Furthermore, volumetric magnetic resonance imaging analyses demonstrated close relationships between olfactory dysfunction and the atrophy of focal brain structures, including the amygdala and other limbic structures. Dementia is one of the most debilitating symptoms of PD. Despite its clinical importance, the development of dementia is still difficult to predict at early stages. As cognitive impairments are known to be associated with poor prognoses in PD, olfactory tests may be a useful tool for the management of PD cases especially in advanced stages.