Neuropsychological tests for detecting prodromal DLB: a systematic review

Background

The prodromal phase of Dementia with Lewy bodies (DLB) remains unexplored and poorly defined. This systematic review scrutinised studies on the earliest cognitive DLB deficits, focusing on the most useful neuropsychological tests.

Methods

From an initial pool of 2307 articles, 37 articles met inclusion criteria including either a prodromal DLB population or DLB cohorts comprehensive of individuals in prodromal or Mild Cognitive Impairment (MCI) due to Lewy Bodies pathology. These studies included comparisons with healthy controls, MCI due to Alzheimer's Disease (MCI-AD), or other aetiologies, and patients with established dementia.

Results

Mild impairments were found in attention, executive functions, visual perception, and working memory in prodromal DLB patients. Prodromal DLB exhibited worse performance in memory and language than healthy controls, while showing better memory but worse performance in visual perception, attention, and executive tasks than MCI-AD. Comparisons in some articles with MCI of other aetiologies confirmed the distinctiveness for prodromal DLB of this pattern of impairment. The most used tests to detect prodromal DLB included the Frontal Assessment Battery (FAB), Digit Symbol Substitution Test (DSST), Stroop test, AX continuous performance test (AX-CPT), digit span backward, Rey-Osterrieth Complex Figure copy, pareidolia test, and Visual Object and Space Perception battery (VOSP).

Conclusions

Prodromal DLB can be detected using test batteries focused on specific cognitive domains and facilitating early diagnosis. It is possible to standardise a targeted test battery centred on specific visuoperceptual and attention domains for early detection of subtle cognitive decline due to Lewy body pathology.