The Hachinski Ischemic Scale is a clinical tool designed to differentiate between types of dementia, particularly vascular dementia and Alzheimer disease. Originally introduced in 1975, the HIS has undergone several modifications and evaluations over the years to improve its diagnostic accuracy and utility ^1,2.

Usage

The scale became widely used in the years following its publication and remains used in outpatient clinical settings in patients with dementia ^1,2,4.

• differentiating dementia types: can distinguish between Alzheimer disease and multi-infarct dementia

• cognitive function correlation: Hachinski ischemic scale scores have been associated with cognitive performance in community-dwelling elderly individuals

• vascular risk assessment: correlates with vascular risk factors, potentially serving as a quick screening tool for vascular cognitive impairment

Limitations

Mixed dementias are unsurprisingly difficult to distinguish using the Hachinski ischemic scale ^3,4.

The scale's predictive value may vary across different ethnic groups, with some studies showing differences between non-Hispanic Whites and Mexican Americans ⁸.

It is important to note, however, that with the advent of better imaging, particularly MRI and, more recently, amyloid PET, the scale is no longer as frequently relied upon in many clinical scenarios ³.

Classification

The Hachinski ischemic scale consists of a set of clinical features that cumulatively generate a score that reflects the likelihood of vascular dementia ^1,2.

• abrupt onset of dementia (2 points)

• stepwise deterioration (1 point)

• fluctuating course (2 points)

• nocturnal confusion (1 point)

• relative preservation of personality (1 point)

• depression (1 point)

• somatic complaints (1 point)

• emotional incontinence (1 point)

• history of hypertension (1 point)

• history of strokes (2 points)

• evidence of associated atherosclerosis (1 point)

• focal neurological symptoms (2 points)

• focal neurological signs (2 points)

The total score is between 0 and 18 and used to categorize patients:

• ≤4 = Alzheimer disease

• ≥7 = vascular dementia

Modified versions

Research has led to the development of optimized versions of the Hachinski ischemic scale ^2,7.

8 single item (Rosen)

In 1980, Rosen et al validated the original 13 item Hachinski ischemic scale against the case histories of patients with a histological diagnosis of either vascular dementia or Alzheimer dementia and proposed a revised set of features, eliminating those that were unhelpful ⁷.

1. abrupt onset of dementia (2 points)

2. stepwise deterioration (1 point)

3. somatic complaints (1 point)

4. emotional incontinence (1 point)

5. history of hypertension (1 point)

6. history of strokes (2 points)

7. focal neurological symptoms (2 points)

8. focal neurological signs (2 points)

Again a total score is calculated, now between 0 and 12 and used to categorize patients ⁷:

• ≤2 = Alzheimer disease

• ≥4 = vascular dementia

7 single item

The 7-item Hachinski ischemic scale is a simplified version using binary scoring (0 or 1) for the seven most discriminative items ².

• abrupt onset (1 point)

• fluctuating course (1 point)

• emotional incontinence (1 point)

• history of stroke (1 point)

• focal neurological symptoms (1 point)

• focal neurological signs (1 point)

• stepwise deterioration (1 point)

Again, if the total score is 2 or higher, a vascular component of cognitive impairment is likely to be present ².

5-item composite

This version measures two meaningful dimensions of information and has shown improved classification of vascular vs non-vascular dementia.

• abrupt onset or stepwise deterioration

• fluctuating course or nocturnal confusion

• depression or emotional incontinence

• history of hypertension or atherosclerosis

• history of strokes or focal neurological symptoms

Unlike the scales above, the 5-item composite score needs to be electronically calculate with dedicated software ².