Cognitive correlates of negative symptoms in behavioral variant frontotemporal dementia: implications for the frontal lobe syndrome

Although both behavioral disturbances and executive impairments of patients with the behavioral variant frontotemporal dementia (bvFTD) seem to depend on early neurodegenerative damages to the prefrontal cortex, the relationship between these two distinct clinical features has been only partially established and represents the focus of the current preliminary neuropsychological study. Ten subsequent bvFTD patients underwent a neuropsychiatric assessment with the Frontal Behavior Inventory and a neuropsychological battery focused on prefrontal functions. Significant correlations were found only between negative symptoms and measures of prevalent medial prefrontal functioning, i.e. decision making under ambiguity (Iowa gambling task) (r = -0.887; p = 0.018) and affective theory of mind (reading the mind in the eyes task) (r = -0.982; p = 0.017). This finding could preliminary support a "frontal lobe syndrome" hypothesis for negative symptoms of bvFTD patients, as proposed for negative symptoms of schizophrenia; the small sample size represents a limit and empirical findings need replication in larger samples of bvFTD patients.