Apathy

Case Discussion

On examination, the patient has reduced verbal and non-verbal expression, otherwise, his neurological examination is normal. Neuropsychological assessment shows preserved cognition. There was no other behavioral or mood disorder. 

Apathy is common, but an under-recognized, neuropsychiatric syndrome consisting of multiple components: reduced initiative, interest and emotional responsiveness¹. Clinically, these symptoms overlap with melancholic depression, negative symptoms of schizophrenia, Parkinson's disease, akinetic disorders and catatonia². The use of rating scales can be useful for determining the presence of apathy as it is prone to misdiagnosis³. For example, in the demonstrated case, 'forgetfulness' is elaborated as reduced interest in sustaining a task (e.g. making a cup of tea), as oppose to an amnesia.

Functional and structural imaging of apathy frequently show abnormalities in the anterior cingulate area^4,5. This area is conceived to be a fundamental component of reward-motivation behavior. Other frontostriatal abnormalities commonly co-exist in apathy. Both anterior cingulate and frontostriatal abnormalities are demonstrated in this PET study, while his MRI brain is unremarkable (MRI not demonstrated in here).

Apathy is a robust clinical correlate of various neurodegenerative disorders and poses a significant emotional burden on the caregiver. The sedentary nature of apathy may lead to self-neglect, malnutrition, venous thrombosis and pressure wound in the patient. Furthermore, apathy can be a prodrome to neurodegenerative diseases such as behavioral variant frontotemporal dementia, corticobasal degeneration and Parkinson's-plus disorders. However, these features are not present in this case, and a sole diagnosis of apathy is made for his mild behavioral impairment.