??? Did You Know ???

Déjà vu (or paramnesia) is the haunting feeling, familiar to most of us, of being sure that we have witnessed or experienced a new situation at some time in the past. This anomaly of memory usually passes within a few seconds or minutes, although for some epileptics it can persist for hours or even days. Déjà vu may occur as part of an epileptic seizure, or between convulsions, and tends to be more frequent when the disorder is in the right temporal lobe, suggesting that it is a neurological anomaly related to improper electrical discharge in the brain, which results in an erroneous sensation of memory.

Huntington’s disease is an inherited progressive neurodegenerative disorder, which affects muscle coordination and leads to general cognitive decline. If a parent carries the gene, there is a 50% chance of the child inheriting it.

Early symptoms include a general lack of coordination and an unsteady gait, which develops into involuntary and uncoordinated, jerky body movements (chorea) and a decline in mental abilities and behavioural and psychiatric problems, and a gradual decline of mental abilities into dementia. The memory decline symptoms, especially those affecting short-term memory, typically appear before any motor function symptoms.

It typically becomes noticeable in middle age, affecting about 1 in every 10,000-20,000 people in the United States for example, and is much more common in people of Western European descent than in those from Asia or Africa. There is no known cure, and no way to stop or even slow the progression of the disease.

It results from a mutation of Htt proteins which is toxic to certain types of cells, particularly in the brain. The mutation of specific gene codes leads to gradual damage to specific areas of the brain, particularly the basal ganglia, although exactly how is not yet fully understood.

As the disease progresses, memory deficits tend to appear, ranging from short-term to long-term memory difficulties, including deficits in episodic, procedural and working memory, ultimately leading to dementia. Memory is affected by damage to the important brain pathways that help the inner subcortical and prefrontal cortex parts of the brain to communicate. This damage occurs mainly in the striatum, but other areas of the brain are also significantly affected as the disease progresses.