Dementia is a “syndrome” not a disease. A syndrome is a set of symptoms and signs that an individual experiences, and others observe, as a change in their usual way of thinking or behaving. What distinguishes dementia from conditions like mild cognitive impairment is that the degree of change interferes with the ability to be independent. The dementia syndrome can be related to one or more diseases of the brain. There can be a lot of overlap between other syndromes, such as movement disorders and dementia. Below are some of the related dementia conditions with resources linked for further information.
Vascular Cognitive Impairment/Dementia
In this form of cognitive impairment, and the more severe condition of dementia, changes in thinking or memory are caused by damage to the blood vessels of the brain. The damage develops due to reduced blood flow in areas of the brain, which can be caused by a variety of conditions, such as stroke, high blood pressure and diabetes. Vascular cognitive impairment and dementia are often responsive to lifestyle changes such as healthy eating, weight management, and blood pressure control may help prevent or control vascular dementia.
Rapidly Progressing Dementias
Rapidly progressing dementias progress quickly, over the course of months to a year. The rate at which they progress is rapid, and is not usually caused by diseases such as Alzheimer’s disease or frontotemporal lobar degeneration. Instead, they can be caused by prion diseases (such as Creutzfeldt-Jakob disease or CJD), infections such as limbic encephalitis, autoimmune conditions, and a by product of antibodies to cancer elsewhere in the body. A thorough evaluation by a neurologist is paramount, as some of these conditions may be treatable.
Parkinson's Disease Dementia
This form of dementia occurs in persons with a diagnosis of Parkinson’s disease in which the primary symptoms, and those that appear earliest, have to do with motor control (tremors, shuffling gait). People with Parkinson’s disease dementia (PDD) may, in addition to the motor symptoms, have trouble with their memory, judgement and other thinking abilities. They may also experience hallucinations and sleep disturbance. PDD is caused by the build-up of the abnormal protein called alpha synuclein. This protein is also implicated in Lewy Body disease, and the symptoms may overlap. Some Alzheimer’s medications may help treat the symptoms of PDD.
Amyotrophic Lateral Sclerosis (ALS)
Amyotrophic Lateral Sclerosis (ALS), also known as Lou Gehrig’s disease, is a progressive neuromuscular disease that affects the brain and spinal cord cells that control movement. Eventually, individuals with ALS lose the ability to voluntarily move their muscles. Some people with ALS develop symptoms of behavioral variant frontotemporal dementia (bvFTD). In many cases, the bvFTD symptoms present first, and then the more classic motor symptoms of ALS develop.