This patient has aphasia, namely the inability to understand speech, although he is able to hear and speak. This can be a finding in a degenerative brain disease like AD. Specifically, he has a Wernicke’s aphasia. The inability to produce speech is also a form of aphasia called Broca’s aphasia. Apraxia is the inability to use tools appropriately. Anomia is the inability to name objects properly. Acalculia is the inability to perform simple arithmetic calculations.