Early onset Lewy Body Dementia is more clinically distinct from Alzheimer Dementia than late onset Lewy Body Dementia

1. Select features distinguish early-onset Lewy Body Dementia from early-onset Alzheimer dementia, including: hallucinations, slowness, apathy and motor deterioration.

2. Late-onset Lewy Body Dementia is more likely to have amnestic features and closely resemble Alzheimer’s disease compared to early-onset Lewy Body Dementia.

Evidence Rating Level: 3 (Average)

Study Rundown: Lewy body dementia (LBD) is one of the most common neurodegenerative diseases after Alzheimer disease (AD). It is characterized by parkinsonian traits, hallucinations, postural instability and altered states of behavior. The present study sought to describe differentiating features between early-onset LBD and (1) AD as well as (2) late-onset LBD. A total of 542 patients were included; 363 had early-onset AD, 147 had late-onset LBD and 32 had early-onset LBD.  Patients with early-onset LBD tended to be older at the time of diagnosis, live fewer years after diagnosis and perform better on the baseline Mini Mental Status Exam (MMSE) than those with early-onset AD. Other differentiating features included: hallucinations and delusions, parkinsonian disordered movements and behavioral symptoms in LBD patients. The primary differences between early- and late-onset LBD included worse scores on neuropsychological testing, poorer memory and reduced medication use in late-onset patients. On pathologic examination, late-onset LBD patients were more likely to have neuritic plaque distributed diffusely in the brain as seen in AD. This retrospective study identified a number of clinical characteristics which help to distinguish AD from LBD, particularly in early stages of disease. It also noted key pathologic and clinical differences between early and late-onset LBD. This work adds to the growing understanding of neurodegenerative diseases and may facilitate earlier, and more accurate diagnosis. A key strength of this work is the large sample size, and the correlation of clinical data with pathologic diagnoses. This work is limited by its retrospective nature and some differences in the size and composition of the subgroups compared. Future research should work to fill these gaps and further validate these findings in a real-world clinical setting.

Click here to read this article in JAMA Neurology

Relevant reading: Distinguishing Lewy body dementia from Alzheimer’s disease

In Depth [case-control study]: A retrospective, case-control study was performed. Study data was derived from the health records of deceased patients who had pathologically-confirmed LBD or AD. Patients were further classified as having early onset disease if they were diagnosed prior to the age of 65 and late-onset disease if they were diagnosed thereafter. Demographic and clinical data were derived from the National Alzheimer Coordinating Center database. 79.9% of the clinically-diagnosed AD patients were also pathologically diagnosed, while only 50% of LDB diagnoses were pathologically confirmed. The strongest differentiating traits between early-onset LBD and AD (p<0.001) were the following: psychosis (46.9% LBD versus 11.6% AD), sleep behavioral disorders (15.6% vs. 6.6%), gait disorder (62.5% vs 22.0%), tremors (53.1% vs. 11.0%), motor slowing (71.9% vs. 26.2%) and depressed mood as per the Geriatric Depression Scale (3.70% vs. 2.66%). The five features thought to best differentiate the two syndromes, listed here with their odds ratios include: initial motor changes (32.01, 95% confidence interval 6.99-146.56), slowness (3.75, 1.43-9.81), apathy (4.67, 1.20-18.20), agitation (0.11, 0.02-0.59) and visual hallucinations (7.95, 2.93-21.57).

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