Onset Patterns and Initial Symptoms of Dementia with Lewy Bodies: Possible Pathophysiological Diversities Deduced from a SPECT Study

Prevalence and clinical implication of microbleeds in dementia with lewy bodies in comparison with microbleeds in Alzheimer's disease

Background

Cerebral microbleeds (MBs) have been well investigated in Alzheimer's disease (AD), but not very extensively in non-AD dementias or in dementia with Lewy bodies (DLB).

Aims

To elucidate the clinical significance of MBs in DLB.

Methods

We compared the prevalence, locations and risk factors for MBs in 59 DLB and 81 AD patients. We visually counted MBs in each of the cortical and subjacent areas (frontal, temporal, parietal and occipital), the basal ganglia and the thalamus, and the brainstem and the cerebellar hemispheres on 1.5-tesla T2*-weighted gradient-recalled-echo MRI images. White matter lesions were semiquantified in fluid-attenuated inversion recovery images according to the Fazekas rating scale.

Results

While the prevalence of MBs was comparable, MBs tended to be more abundant in DLB than in AD in all brain areas with the exception of the occipital lobes. The number of MBs was positively associated with the severity of white matter lesions but not with other vascular risk factors in either AD or DLB. The presence of MBs could be associated with cognitive impairment at onset. MB-positive DLB patients showed less impairment on ¹²³I-metaiodobenzylguanidine myocardial scintigraphy (MIBG scintigraphy) images, supporting the notion of an inverse relationship between vascular lesions and Lewy body pathology.

Conclusion

It was suggested that an intricate association between Lewy body pathology, AD-type pathologies and vascular lesions seems to be related to the initial symptoms and results of MIBG scintigraphy in DLB.

Can the 'head-turning sign' be a clinical marker of Alzheimer's disease?

Aims

To investigate the incidence and severity of the ‘head-turning sign’ (HTS), i.e. turning the head back to the caregiver(s) for help, in patients with various dementias and discuss its clinical specificity in Alzheimer's disease (AD).

Methods

We investigated the incidence and severity of HTS while administering a short cognitive test (the revised Hasegawa Dementia Rating Scale: HDSR) in outpatients with AD [125 patients, including 4 with AD + vascular dementia (VaD)], 8 with amnestic mild cognitive impairment (aMCI), 34 with dementia with Lewy bodies (DLB), 8 with progressive supranuclear palsy (PSP) and 6 with VaD.

Results

Significant differences were found among the 5 disease groups in the incidence and severity of HTS, and HDSR scores. Given the significant differences between AD and DLB in post hoc analyses, patients were dichotomized into AD-related (AD and aMCI) and AD-nonrelated (PSP, DLB and VaD) groups. Both incidence (41 vs. 17%, p = 0.002) and severity of HTS (0.80 ± 1.13 vs. 0.21 ± 0.60, p = 0.001) were significantly higher in the AD-related group, while average age and HDSR scores were comparable between both groups. AD-related disease, female gender and low HDSR score contributed significantly to the occurrence and severity of HTS.

Conclusions

HTS can be a clinical marker of AD and aMCI, and may represent a type of excuse behavior as well as a sign of dependency on and trust in the caregivers.