Objective: These studies investigated whether non-demented ALS patients display impairments on tests of emotional decision making and social and emotional cognition, sensitive to frontal variant Frontotemporal Dementia (fvFTD). Previous studies have shown predominant executive dysfunction and dorsolateral prefrontal involvement in ALS, but evidence of other prefrontal dysfunction implicated in fvFTD is sparse.
Method: In Study A, 19 ALS patients and 20 healthy controls undertook a test of affective decision making, modified Iowa Gambling Task (IGT). Behavioral measures included the Frontal Systems Behavior Scale. In Study B, 14 ALS patients and 20 controls undertook tests of social and emotional cognition (Judgment of Preference based on eye gaze, the Mind in the Eyes, recognition of Facial Expressions of Emotion).
Results: In Study A, ALS patients demonstrated a significantly different performance profile from healthy controls on the IGT and did not learn to avoid the disadvantageous stimuli (Block 3, d = 0.60, Block 4 days = 0.68). Behavior ratings showed increased apathy from premorbid levels. In Study B, ALS patients were impaired on attentionally demanding (d = 3.12) and undemanding (d = 7.52) conditions of the Judgment of Preference task, despite many showing intact executive functions. A smaller subset showed impaired emotion recognition. Behavior change was also evident.
Conclusions: The findings reveal a Theory of Mind deficit on a simple test that was dissociated from the presence of executive dysfunction and suggests a profile of cognitive and behavioral dysfunction indicative of a subclinical fvFTD syndrome. The relative contribution of prefrontal pathways to the cognitive profile in ALS is considered.
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