Visual, olfactory, auditory and tactile hallucinations are common in elderly people, according to Carefect. Elderly people may also experience gustatory hallucinations, but these are a rarer type of hallucination.
Visual hallucinations occur when people see other people or things that are not really there, explains Carefect. In addition to objects and people, elderly individuals may also see nonexistent patterns or lights during visual hallucinations. It is possible for conditions such as depression and schizophrenia to produce visual hallucinations, but in the absence of auditory hallucinations, these types of hallucinations are not usually a result of a mental health condition, notes an article published by the National Center for Biotechnology Information. Other possible causes that doctors should investigate in elderly patients include nervous system, vascular and ophthalmological diseases.
Olfactory hallucinations involve smelling nonexistent odors, notes Carefect. This type of hallucination can occur due to epilepsy or nerve damage in the portion of the brain associated with the sense of smell. The perceived smells are usually unpleasant, but it is sometimes possible to smell pleasant scents, such as flowers or a food the patient enjoys.
An auditory hallucination occurs when someone hears a nonexistent sound, explains Carefect. In the case of elementary auditory hallucinations, people hear sounds such as whistles and hissing, while complex auditory hallucinations involve hearing things like voices and music. Complex auditory hallucinations are more likely to result from mental illness than elementary auditory hallucinations, but they can also result from conditions such as autoimmune diseases and endocrine problems.