The Genesis of Graphic Perseverations in Alzheimer's Disease and Vascular Dementia

Perseveration is the involuntary production of iterative responses. This study explored graphic perseverative errors in Alzheimer's disease and vascular dementia, to comprehend the neuropsychological correlates of this behavior.

We performed a retrospective analysis of graphic productions in 114 individuals with clinical diagnosis of Alzheimer's disease and in 63 individuals with clinical diagnosis of vascular dementia, who completed frontal-executive, visuo-spatial, visuo-constructional, and verbal memory tests. For assessing perseverative behavior, we considered recurrent perseverations (inappropriate re-drawing of a figure drawn in a previous trial) and continuous perseverations (inappropriate replication of the same figure or of its element within one trial) produced in a standard copying task.

Two or more graphic perseverative errors occurred in 66/114 individuals with Alzheimer's disease (57.9%) and in 31/63 individuals with vascular dementia (49.2%). Participants with moderate-to-severe dementia produced a significantly higher number of perseverations than individuals with mild dementia. Logistic regression revealed a significant relationship of graphic perseverations with frontal and visuo-constructive impairments, in both Alzheimer's disease and vascular dementia.

Graphic perseverations are frequent in both Alzheimer's disease and vascular dementia. Frontal-executive defects can hamper inhibition of iterative graphic productions. Identification of graphic perseverations can be useful for detection and monitoring of frontal-executive impairments throughout the disease course in individuals with dementia.