Background: Several groups have found that a significant percentage of patients with amyotrophic lateral sclerosis (ALS) have cognitive impairment. Here we investigate whether the amygdala, a temporal lobe structure, is affected by ALS.
Methods: We asked patients with ALS to judge the approachability of unfamiliar faces. We showed subjects 60 faces and asked, "If you were in a strange town at dusk, would you ask this person for directions to a hotel?"
Results: More than half of our patients had similar behavioral characteristics to patients with bilateral amygdala damage, approaching even faces that controls found unapproachable. This pattern was not associated with frontal lobe dysfunction on neuropsychological testing.
Discussion: Patients with amyotrophic lateral sclerosis (ALS) rated highly approachable faces similarly to controls but rated many faces approachable that controls deemed unapproachable. Like patients with amygdala damage, who show the same behavior, patients with ALS may not recognize the threat expressed through facial clues that raise concern in controls. Thus, more patients with ALS may have disease involvement outside of the motor cortex than previously suggested, manifesting as frontal lobe, temporal lobe, or frontal and temporal lobe dysfunction.