Visuospatial Abilities May Negatively Impact Theory of Mind in Parkinson, Study Says

A person’s theory of mind (ToM)—the ability to recognize others’ mental states—often deteriorates when they have Parkinson’s disease. Cognitive status may be affected by the relationship of Parkinson disease (PD) and affective ToM through the involvement of visuospatial abilities (VSA), according to a recent study.

The study, published in Neuropsychiatric Disease and Treatment, involved 65 patients who were diagnosed with idiopathic PD and 51 controls who were matched for age, gender, and educational level. All participants completed a visual affective ToM task and their cognitive performance was assessed using the Montreal Cognitive Assessment. Psychiatric symptoms were also measured using the Brief Psychiatric Rating Scale (BPRS-E).

“ToM is considered to be a complex neuropsychological ability, mediated by an elaborate neuroanatomical network, which includes the medial prefrontal cortex, the temporal lobe (superior temporal sulcus region and the temporal pole), the temporoparietal junction, and the amygdala,” explained the authors. “ToM abilities have been investigated in various neurodegenerative diseases, several studies showing impaired ToM performance in PD. Certain authors reveal deficits only regarding the cognitive aspect of ToM, while others also suggest supplementary reduced performance in the affective component of ToM.”

The analysis revealed that affective ToM abilities were preserved in early PD patients yet declined as the disease progressed. Additionally, the researchers reported deficits in cognitive functioning predicted deficiencies in affective ToM.

The relationship between PD and affective ToM were mediated by attention, executive functions, and VSA; however, only VSA impairment had a specific negative impact on affective ToM, according to the results. Therefore, the researchers noted that 41% of the total effects of attention and executive functions on affective ToM was mediated by visuospatial skills.

“Attention deficits negatively impact on executive functions, which adversely influence visuospatial abilities, which in turn lead to affective ToM deficiencies. Although attention and executive functions do not act as individual mediators, they are part of an extended causal chain that ultimately involves visuospatial abilities,” concluded the authors. “Visuospatial skills may have a direct involvement in affective ToM impairments displayed by PD patients, as assessed with a visual task.”

Reference

Romosan A, Dehelean L, Romosan R, et al. Affective theory of mind in Parkinson’s disease: The effect of cognitive performance [published online August 30, 2019]. Neuropsychiatric Disease and Treatment. doi.org/10.2147/NDT.S219288.