Predominant first Alzheimer’s symptoms vary with diagnosis age

By Eleanor McDermid, Senior medwireNews Reporter

The symptoms presented by patients newly diagnosed with Alzheimer’s disease (AD) vary with age, with younger patients less likely to have initial memory problems, research shows.

Instead, these patients often presented with symptoms such as trouble with visuospatial function, report Josephine Barnes (National Hospital for Neurology and Neurosurgery, London, UK) and co-workers.

They note that the 2011 US National Institute on Aging–Alzheimer’s Association workgroups guidelines acknowledge that AD patients can present without initial memory problems, and include behavioural symptoms in the diagnostic criteria.

“Appreciation that nonmemory first symptoms occur in AD, particularly in younger cases, is important so that patients have a less tortuous route to diagnosis”, write Barnes et al in Alzheimer’s & Dementia.

Their study included 7815 patients from the US National Alzheimer’s Coordinating Center (NACC) dataset, who had definite or probable AD that was not caused by a concurrent psychiatric or neurological disorder.

Although memory impairment was the most frequent predominant presenting symptom, its frequency fell with younger age, from 94% in patients older than 79 years to 74% of those younger than 60 years.

Among patients younger than 60 years, 8% had judgement/problem-solving difficulties as their predominant presenting symptom, 7% had language and 7% visuospatial problems, 3% had attention/concentration problems and the remainder had other cognitive complaints.

This was confirmed in neuropsychological tests, in which a younger age at presentation was associated with poorer scores for visuospatial function (ability to copy a pentagon), and for attention and working memory (digit span forward and backward tests).

However, language ability was actually more impaired in older than younger patients, which the researchers attribute to the accrual of language deficits in older patients and to the difference between the perception of a problem and its objective measurement.

The researchers stress the need for full neuropsychological testing of patients with suspected AD. “Better awareness of nonmemory symptoms and more comprehensive testing would allow for improved services for patients: for example, the development of appropriate information materials for those with visuospatial problems and support services for those who experience behavioral symptoms.”

Behavioural symptoms also differed somewhat according to age at presentation. Depression was more common among younger patients, at 30% versus 19% of patients younger than 60 years and older than 79 years, respectively. The frequency of psychosis rose from 3% in the youngest to 7% in the oldest age group, and the absence of behavioural symptoms became more common with older age, at a corresponding 17% and 26%.

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