Study suggests that non-invasive tests are able to predict type of dementia at an early stage to enable correct treatment
19 May 2017
A study by researchers from the UCL Division of Psychiatry, including then PhD student Dilman Sadiq and her supervisor Zuzana Walker was published on 11, May 2017 in the Journal of Alzheimer’s disease. It shows the potential for clinicians to be able to diagnose dementia with Lewy bodies at a much earlier stage than is currently possible, in order to recommend the necessary disease-specific therapy.
Dementia with Lewy bodies is often misdiagnosed as Alzheimer’s disease due to similarities in clinical presentation. Both of these diseases are preceded by a prodromal period, whereby patients’ symptoms are mild and often not easily detectable. This prodromal period is widely understood as Mild Cognitive Impairment.
Until now, diagnosis for the two most common forms of dementia (Alzheimer’s disease and dementia with Lewy bodies) was only possible at a late stage of the disease, once symptoms have fully manifested, meaning early targeted treatment was not possible.
However, for the best outcome, patients need pathology-specific treatment during the prodromal stage or earlier. As treatment can be different for dementia with Lewy bodies than it is for Alzheimer’s disease, early differentiation between the two types of dementia is necessary.
The 20-year longitudinal study found that of 560 patients presenting with Mild Cognitive Impairment, those who went on to develop dementia with Lewy bodies performed significantly worse on the letter fluency test – a test associated with frontal-executive functioning - and cognitive tests that involved visuospatial functioning, compared to those who went on to develop Alzheimer’s disease or whose condition did not worsen. Mild Cognitive Impairment patients who later converted to dementia with Lewy bodies however performed better on tests of memory. Moreover, at the prodromal stage, these patients were more likely to experience Parkinsonism and REM behaviour sleep disorder.
Findings from this study support the feasibility of distinguishing dementia with Lewy bodies from Alzheimer’s disease at the prodromal stage, based on patients’ performance on non-invasive cognitive and clinical tests. This has important implications as dementia with lewy bodies is commonly misdiagnosed as AD and it is becoming increasingly more important to diagnose dementia as accurately and as early as possible. Indeed, findings from a number of recent clinical trials suggest that disease-modifying therapies may only be effective at the stage of Mild Cognitive Impairment, or earlier.