TIME TAKEN to process written words may serve as a reliable predictor of an individual’s risk of developing Alzheimer’s disease, according to a study presented by researchers at the University of Birmingham, Birmingham, the University of Kent, Kent, UK, and the University of California, Davis, Oakland, California, USA.
The study was centred around patients with mild cognitive impairment (MCI), a condition which results in very small, but noticeable difficulties in memory and cognition. Although people who develop MCI do not experience it on such a large scale as those who have Alzheimer’s disease, it is known that patients with MCI may go on to develop Alzheimer’s.
Previous studies have shown that, on average, it takes the human brain 250 milliseconds to process a written word, as determined using an electroencephalogram (EEG). This study used the EEG technique to assess the brain activity of 25 individuals whilst they were being shown words on a computer screen. The individuals were all senior citizens, typically ≥65 years old, who either had MCI only or had been diagnosed with Alzheimer’s disease within 3 years of a MCI diagnosis. The researchers found that in those who developed Alzheimer’s disease the time taken to process written words was longer than in those who did not. Study co-author Dr Katrien Segaert, University of Birmingham, Birmingham, UK, said the results were unexpected, explaining that: “…language is usually affected by Alzheimer’s disease in much later stages of the onset of the disease.” She further speculated that: “It is possible that this breakdown of the brain network associated with language comprehension in MCI patients could be a crucial biomarker used to identify patients likely to develop Alzheimer’s disease.”
The researchers hope to scale up the study and test whether the same results are seen in a larger sample size. In which case, it may be possible to use slower word processing as a specific predictor of Alzheimer’s disease, or perhaps a general marker of dementia involving the temporal lobe. With these findings established, it may be possible to develop a preventative method of treatment, as well as allowing the non-invasive EEG technique to be used as part of a routine medical examination when visiting a general practitioner due to concerns over memory or cognitive difficulties.
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