Parkinson's disease develops in people over the age of 50 as a result of the destruction of dopamine-producing cells in the brain. The significant decrease in dopamine interferes with the communication between the brain and muscles, resulting in movement problems. But Parkinson's disease can also cause patients to have hallucinations, in which they perceive something that does not exist. The Parkinson's Disease Society notes that some Parkinson's disease patients have hallucinations as a result of their medications. These hallucinations can affect different senses.
Visual Hallucinations
Some Parkinson's disease patients may have visual hallucinations, in which they see a non-existent object. Babak Tousi, M.D., and Thayagaran Subramanian, M.D., authors of the Clinical Geriatrics article “Hallucinations in Parkinson's Disease: Approach and Management,” point out that 30 percent of Parkinson's disease patients have visual hallucinations, and they are complex: they may see more than one object. Patients may see people or animals that aren't there. These hallucinations do not produce any sound and can last for a short or long period of time. If patients see another person in their visual hallucinations, they may think of that hallucination as a companion, according to the Parkinson's Disease Society. For some Parkinson's disease patients, visual hallucinations may result from poor vision.
Auditory Hallucinations
Patients who hear sounds that do not have a tangible source but do not see an accompanying object have auditory hallucinations. Tousi and Subramanian explain that 10 percent of Parkinson's disease patients have this type of hallucination. The Parkinson's Disease Society adds that many of the hallucinations are pleasant, but if a patient does not know that she is hallucinating, she may become frightened and have a hard time coping.
Tactile Hallucinations
While rare, Tousi and Subramanian note that Parkinson's disease patients sometimes have tactile hallucinations, in which they feel someone or something touching them, without seeing or or hearing anything. Tactile hallucination may be disturbing for patients if they do not know that they are hallucinating.
