Behavioral abnormalities have been reported in patients with amyotrophic lateral sclerosis (ALS) but their aetiology is not yet clearly defined. We report on the case of a 48 years old woman with long standing bulbar onset ALS referred to our department for brain perfusion scan for the evaluation of behavioral and emotional disorders. The patient's scores on the neuropsychological tests were satisfactory while magnetic resonance imaging showed no structural brain abnormalities. However, cerebral blood flow imaging with single photon emission tomography with technetium-99m-hexamethyl propylamine oxime demonstrated bilateral frontal cortex hypoperfusion, as well as perfusion defects in the left parietal, temporal and occipital lobes. In conclusion, the reduced regional cerebral blood flow in the frontal lobes might be suggestive of underlying cortical disturbance and potentially explain the patient's symptoms.