Apathy in Parkinson's disease: clinical features, neural substrates, diagnosis, and treatment

Abstract

Normal maintenance of human motivation depends on the integrity of subcortical structures that link the prefrontal cortex with the limbic system. Structural and functional disruption of diff erent networks within these circuits alters the maintenance of spontaneous mental activity and the capacity of aff ected individuals to associate emotions with complex stimuli. The clinical manifestations of these changes include a continuum of abnormalities in goal-oriented behaviours known as apathy. Apathy is highly prevalent in Parkinson's disease (and across many neurodegenerative disorders) and can severely aff ect the quality of life of both patients and caregivers. Diff erentiation of apathy from depression, and discrimination of its cognitive, emotional, and auto-activation components could guide an individualised approach to the treatment of symptoms. The opportunity to manipulate dopaminergic treatment in Parkinson's disease allows researchers to study a continuous range of motivational states, from apathy to impulse control disorders. Parkinson's disease can thus be viewed as a model that provides insight into the neural substrates of apathy.

Differential impact of behavioral, social, and emotional apathy on Parkinson's disease

“…Apathy, a disorder of motivation characterized by reduced self‐initiated goal‐directed behavior,1 is very common in Parkinson's disease (PD) and associated with diminished quality of life 2, 3, 4. Theoretical accounts5 and new evidence6 suggest that rather than being a unitary construct, apathy is multidimensional, involving behavioral, cognitive, executive, social, and emotional domains.…”

Apathy in Mild Parkinson’s Disease: Neuropsychological and Neuroimaging Evidence

“…Only a limited number of neuroimaging studies have investigated apathy in PD [29]. Apathy has been associated with deficits of the prefrontal-basal ganglia system [30].…”

Multidimensional model of apathy in older adults using partial least squares—path modeling

“…This result is not surprising as executive dysfunction has been involved in apathetic manifestations in Parkinson's disease (Pagonabarraga et al 2015), Alzheimer's disease ( L a n d e s e t a l . 2 0 0 1 ) , a n d s c h i z o p h r e n i a (Konstantakopoulos et al 2011).…”

“…It constitutes a major neuropsychiatric symptom following both acquired and neurodegenerative neurological disorders such as stroke (Caeiro et al 2013), brain injury (Lane-Brown and Tate 2009), Alzheimer's disease (Levenson et al 2014), or Parkinson' disease (Pagonabarraga et al 2015). In these neurologic disorders, apathy has been constantly associated with functional impairments (Jorge et al 2010;Landes et al 2001), caregiver burden, anxiety, and depression (Ishii et al 2009;Lou et al 2015).…”

“…Thus, this study aimed to identify how these factors (i.e., executive functions, depression, anticipatory and consummatory pleasure, sensitivity to reward and punishment, and subjective quality of life) are related to the distinct dimensions of apathy in a sample of cognitively normal older adults. From a clinical perspective, such an approach would guide the development of an individualized treatment of apathetic manifestations that in cognitively normal older adults (Pagonabarraga et al 2015).…”