Differentiating between Vascular and Alzheimer's Dementia
There are several points that can help differentiate between these two types of dementia. Hachinski Ischemic Score is a 13-item tool based on these factors on which a score of seven or above shows vascular dementia, while a score of three or lower points towards the diagnosis of Alzheimer's dementia. The presence of the items (given below) on this scale in a patient favours a diagnosis of vascular dementia.
Here, the patient had an abrupt onset after he had a fall, a stepwise progression as showed by worsening after the falls, which might have been unrecognized TIAs and the course was fluctuating, as once he even improved slightly. However, the change in his personality, as suggested by his daughter when she said "he is no more the person he used to be" goes in favour of Alzheimer's dementia.
- Abrupt onset
- Stepwise deterioration
- Fluctuating course
- Nocturnal confusion
- Relative preservation of personality
- Somatic complaints
- Focal neurological signs
- Emotional incontinence
- History of hypertension
- History of strokes
- Evidence of associated atherosclerosis
- Focal neurological symptoms
It can be especially useful to know these factors, to help quickly differentiate between the two common types of dementia. However, it is important to remember, as mentioned earlier that these two types of dementia are often comorbid. Mixed dementia is the term used when ’a patient has features of both and it is not possible to clearly separate one type’. Some of these features have been found to be more specific for vascular dementia, and thus all the items do not carry the same score. For more details on the topic, please refer to some of the sources below.
Hachinski VC, Iliff LD, Zilhka E, Du Boulay GH, McAllister VL, Marshall J, Russell RW, Symon L. “Cerebral blood flow in dementia.” Arch Neurol. 1975;32:632-7.
Molsa PK, Paljarvi L, Rinne JO, Rinne UK, Sako E. “Validity of clinical diagnosis in dementia: a prospective clinicopathological study.”J Neurol Neurosurg Psychiatry. 1985;48:1085-90.
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