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Meta-analysis of the Hachinski Ischemic Score in pathologically verified dementias
J T Moroney1, E Bagiella, D W Desmond
1Department of Neurology, Columbia University, College of Physicians and Surgeons, New York, NY, USA.
Insights
The Hachinski Ischemic Score (HIS) effectively differentiates Alzheimer's disease (AD) from multi-infarct dementia (MID). However, accurately diagnosing mixed dementia remains challenging, suggesting a need for refined diagnostic tools.
Area of Science:
- Neurology
- Gerontology
- Pathology
Background:
- Differentiating dementia subtypes is crucial for effective treatment and management.
- The Hachinski Ischemic Score (HIS) is a clinical tool used to distinguish between Alzheimer's disease (AD) and multi-infarct dementia (MID).
- Mixed dementia, a combination of AD and cerebrovascular disease, presents diagnostic challenges.
Purpose of the Study:
- To evaluate the Hachinski Ischemic Score's (HIS) accuracy in differentiating pathologically verified Alzheimer's disease (AD), multi-infarct dementia (MID), and mixed dementia.
- To identify specific HIS items that best discriminate between these dementia subtypes.
Main Methods:
- A meta-analysis of clinical data, HIS scores, and pathological diagnoses from 312 dementia patients across six sites.
- Receiver-operator characteristic (ROC) curve analysis to determine optimal HIS cutoffs for AD and MID.
- Logistic regression to calculate odds ratios (OR) for individual HIS items in differentiating diagnostic groups.
Main Results:
- The HIS demonstrated good performance in differentiating AD from MID, with optimal cutoffs of <= 4 for AD and >= 7 for MID (sensitivity 89.0%, specificity 89.3%).
- Specific HIS items like stepwise deterioration, fluctuating course, hypertension, history of stroke, and focal neurologic symptoms were key in distinguishing MID from AD.
- The HIS showed limited ability to differentiate MID from mixed dementia and AD from mixed dementia, indicating diagnostic difficulties for mixed dementia.
Conclusions:
- The Hachinski Ischemic Score (HIS) is valuable for distinguishing Alzheimer's disease (AD) from multi-infarct dementia (MID).
- Clinical diagnosis of mixed dementia remains difficult using the HIS alone.
- Future research should incorporate additional clinical and neuroimaging variables to refine the HIS for improved mixed dementia identification.
Abstract:
Our objectives were to investigate the utility of the Hachinski Ischemic Score (HIS) in differentiating patients with pathologically verified Alzheimer's disease (AD), multi-infarct dementia (MID), and "mixed" (AD plus cerebrovascular disease) dementia, and to identify the specific items of the HIS that best discriminate those dementia subtypes. Investigators from six sites participated in a meta-analysis by contributing original clinical data, HIS, and pathologic diagnoses on 312 patients with dementia (AD, 191; MID, 80; and mixed, 41). Sensitivity and specificity of the HIS were calculated based on varied cutoffs using receiver-operator characteristic curves. Logistic regression analyses were performed to compare each pair of diagnostic groups to obtain the odds ratio (OR) for each HIS item. The mean HIS (+/- SD) was 5.4 +/- 4.5 and differed significantly among the groups (AD, 3.1 +/- 2.5; MID, 10.5 +/- 4.1; mixed, 7.7 +/- 4.3). Receiver-operator characteristic curves showed that the best cutoff was < or = 4 for AD and > or = 7 for MID, as originally proposed, with a sensitivity of 89.0% and a specificity of 89.3%. For the comparison of MID versus mixed the sensitivity was 93.1% and the specificity was 17.2%, whereas for AD versus mixed the sensitivity was 83.8% and the specificity was 29.4%. HIS items distinguishing MID from AD were stepwise deterioration (OR, 6.06), fluctuating course (OR, 7.60), hypertension (OR, 4.30), history of stroke (OR, 4.30), and focal neurologic symptoms (OR, 4.40). Only stepwise deterioration (OR, 3.97) and emotional incontinence (OR, 3.39) distinguished MID from mixed, and only fluctuating course (OR, 0.20) and history of stroke (OR, 0.08) distinguished AD from mixed. Our findings suggest that the HIS performed well in the differentiation between AD and MID, the purpose for which it was originally designed, but that the clinical diagnosis of mixed dementia remains difficult. Further prospective studies of the HIS should include additional clinical and neuroimaging variables to permit objective refinement of the scale and improve its ability to identify patients with mixed dementia.