Relationships between lewy and tau pathologies in 375 consecutive non-Alzheimer's olfactory bulbs

DCARD checklist: A simple screening tool for Lewy body disease-related early symptoms in memory clinic

OBJECTIVE

Despite the relatively high prevalence of Lewy body disease (LBD) in over middle-aged people, physicians and patients show poor awareness of early symptoms. We examined the clinical utility of a simple checklist for screening for the early symptoms of LBD.

METHODS

We administered a 7-item screening checklist assessing the five representative early symptoms of LBD (dizziness, constipation, anosmia, REM sleep behavior disorder, and depression: the acronym is "DCARD") to 450 consecutive individuals who visited the memory clinic at our university hospital. The aim of this retrospective study was to evaluate the usefulness of the DCARD checklist in differentiating neurocognitive disorders (NCD) due to LBD (i.e., NCD with Lewy bodies and NCD due to Parkinson's disease) from NCD due to non-LBD (e.g., Alzheimer's disease). We also associated the DCARD score with current depressive symptoms using the 15-item Geriatric Depression Scale (GDS-15).

RESULTS

Fifty-five participants (12.2 %) had a higher DCARD score (≥4 out of 7 points) regardless of the global cognitive level. The subgroup with higher DCARD scores had higher GDS-15 scores than the subgroup with lower DCARD scores (p < 0.001). With a DCARD cut-off score of 3/4, the sensitivity and specificity were 65 % and 95 %, respectively, for diagnosing NCD due to LBDs. Receiver operating characteristic curve analysis showed good discriminatory ability (area under the curve: 0.89).

CONCLUSIONS

This simple LBD screening checklist may be useful as a diagnostic tool for the early diagnosis of LBD in memory clinics.

CLINICAL TRIAL REGISTRY

None.

Olfactory Bulb Amyloid-β Correlates With Brain Thal Amyloid Phase and Severity of Cognitive Impairment

The Alzheimer disease (AD) neuropathological hallmarks amyloid β (Aβ) and tau neurofibrillary (NF) pathology have been reported in the olfactory bulb (OB) in aging and in different neurodegenerative diseases, which coincides with frequently reported olfactory dysfunction in these conditions. To better understand when the OB is affected in relation to the hierarchical progression of Aβ throughout the brain and whether OB pathology might be an indicator of AD severity, we assessed the presence of OB Aβ and tau NF pathology in an autopsy cohort of 158 non demented control and 173 AD dementia cases. OB Aβ was found in less than 5% of cases in lower Thal phases 0 and 1, in 20% of cases in phase 2, in 60% of cases in phase 3 and in more than 80% of cases in higher Thal phases 4 and 5. OB Aβ and tau pathology significantly predicted a Thal phase greater than 3, a Braak NF stage greater than 4, and an MMSE score lower than 24. While OB tau pathology is almost universal in the elderly and therefore is not a good predictor of AD severity, OB Aβ pathology coincides with clinically-manifest AD and might prove to be a useful biomarker of the extent of brain spread of both amyloid and tau pathology.