Dementia, also referred to as senility, is not a disease in and of itself. It is a word used to describe a specific cluster of symptoms caused by diseases that affect brain functioning, according to Medline Plus. Symptoms include cognitive impairment resulting in decreased ability to plan or solve problems, language trouble, memory deficits and changes in personality accompanied by agitation or trouble controlling emotions. Daily personal care, such as eating or dressing oneself may also be affected. Dementia can be caused by many diseases, such as Alzheimer's, stroke and Lewy body disease.
Lhermitte's Hallucinosis
According to a case report about an elderly patient with mild dementia and hallucinations written by Raphael J. Leo, M.D. and Kristin Stievater Ahrens, M.D. and published in the journal "Psychosomatics," hallucinations involving animals or people have been associated with damage to the midbrain area or brainstem, and are referred to as Lhermitte's Hallucinosis. The brain damage can be detected with a magnetic resonance imaging, or MRI, scan. Often, patients do not find the hallucinations to be disturbing, and can even understand they are not real. Lhermitte's Hallucinosis tends to be rare, but should be considered in cases displaying these symptoms.
Dementia with Lewy Bodies
According to the Family Caregiver Alliance National Center on Caregiving, dementia with Lewy bodies is second only to Alzheimer's disease in dementias that affect the elderly. Approximately 20 percent of reported dementia cases are diagnosed as dementia with Lewy bodies. Lewy bodies are smooth lumps of protein located on certain nerve cells in the brain. Symptoms of this disease include cognitive and memory impairment associated with dementia, mild motor symptoms such as movement problems, mild tremor and muscle stiffness similar to Parkinson's Disease and vivid hallucinations. There can be frequent fluctuation of mental symptoms. The cause and risk factors associated with dementia with Lewy bodies is unknown. It is also unclear whether there is a genetic component.
Alzheimer's Disease
The most common cause of dementia is Alzheimer's disease. This disease is associated with several physical changes in the brain including the loss of cholinergic neurons, neurofibrillary tangles and amyloid plaques. Approximately 20 to 40 percent of Alzheimer's patients experience hallucinations, which may be associated with the loss of cholinergic neurons. A study by Jeffrey Cummings, et al., published in "The Journal of Alzheimer's Disease," suggests that rivastigmine, a cholinesterase inhibitor, elicits a greater treatment response in patients with hallucinations.
References
- "Psychosomatics"; Visual Hallucinations in Mild Dementia; Raphael J. Leo, M.D. and Kristin Stievater Ahrens, M.D.; August 1999
- Family Caregiver Alliance: National Center on Caregiving: Dementia With Lewy Bodies
- "The Journal of Alzheimer's Disease"; Effects of Rivastigmine in Alzheimer's Disease Patients with and Without Hallucinations; Jeffrey Cummings, Murat Emre, Dag Aarsland, Sibel Tekin, Nalina Dronamraju and Roger Lane; April 2010
- United States National Library of Medicine: MedlinePlus: Dementia
