The present investigation is a pilot study exploring the ability of AD patients to distinguish auditorily between the two Norwegian word tones, compared to elderly controls and previous investigations of patients with aphasia. Aphasic patients have been shown to have reduced perception of tonal contrasts as a result of a phonological breakdown. The cognitively weakest AD patients show reduced discriminative ability compared to the controls. Since AD is a heterogeneous neurodegenerative disorder and aphasia a symptom of a more distinct cerebral damage, it cannot be assumed that impaired tonal discrimination is the result of the same underlying linguistic deficiency in the two groups. The study indicates that the AD patients' discriminative problem may be associated with reduced semantic abilities, possibly combined with a phonological breakdown. A test of this type might be used, in conjunction with other tests, to help distinguish between elderly patients with and without AD or aphasia.