A disorder that is characterised by a serious decline in mental faculties, particularly in the loss of memory, as well as impairment of at least one other cognitive function. This group of disorders may impair what we know or even who we are. There are a number of different dementias, but the commonest division is into cortical dementias and sub-cortical dementias:
• cortical dementias – as well as memory impairment, sufferers may also experience aphasia , personality changes such as impulsiveness, and progressive deterioration of a number of other faculties. Alzheimer’s disease is the best known of the cortical dementias
• sub-cortical dementias – memory impairment here is experienced as an inability to retrieve information from long-term storage. Aphasia is not present, but personality deterioration is. An example is Huntington’s disease – a degeneration of cognition, emotion and movement. This has a dramatic effect on personality, and leads to depression, instability and anxiety.
Other dementias have been associated with HIV and AIDS, meningitis, drug abuse and advanced cases of syphilis. Treatment for the dementias is tricky because they affect so many different areas of the brain and involve so many different neurochemicals. Diagnosis involves taking a complete history of the patient (for example checking for alcohol abuse or a family history of Alzheimer’s disease); checking for specific cognitive impairments; and using brain imaging techniques to look for obvious physical causes such as brain lesions. The main type of treatment for dementias is drug treatments, which focus on the neurotransmitters that seem central to the action of the dementia concerned. Recent research has attempted to develop chemicals that will stimulate the development of neural pathways to replace those that have been destroyed.