Sandhoff disease A rare genetic lipid storage disorder resulting in the progressive deterioration of the central nervous system. Although sandhoff disease is a severe form of tay-sachs disease prevalent in people of European Jewish descent, it is not limited to any ethnic group. onset of the disorder usually occurs at 6 months of age.
Symptoms progressive weakness, startle reaction to sound, early blindness, progressive mental deterioration, frequent respiratory infections, an abnormally enlarged head and doll-like facial appearance, cherry-red spots in the back of the eyes, seizures, and muscle contractions.
The condition is caused by a deficiency of the enzyme hexosaminidase which results in the buildup of certain fats in the brain and other organs of the body.
There is no specific treatment for Sandhoff disease. Treatment is symptomatic and supportive. The prognosis for patients with sandhoff disease is poor; death usually occurs by age three and is generally caused by respiratory infections.
Schilder's disease A rare, progressive demyeli-nating disorder which usually begins in childhood, featuring widespread destruction of the myelin sheath of the neurons in the cerebral hemispheres of the brain. The disorder is a variant of
Treatment for the disorder is similar to that for standard multiple sclerosis therapy, and includes corticosteroids, beta-interferon or immunosuppres-sive therapy, and symptomatic treatment. Like multiple sclerosis, Schilder's disease is unpredictable. For some patients, the disorder progresses with a steady, unremitting course; others may experience significant improvement and remission. in some cases, schilder's disease is fatal.
schizencephaly An extremely rare developmental disorder characterized by abnormal clefts in the brain's cerebral hemispheres. schizencephaly is a form of porencephaly in which there is a cavity in the cerebral hemispheres.
Symptoms individuals with clefts in both hemispheres are often developmentally delayed, with delayed speech and language skills. individuals with smaller clefts in only one hemisphere are often paralyzed on one side of the body, but may have normal intelligence. patients with schizencephaly may also have varying degrees of abnormally small head, mental retardation, partial or complete paralysis, and reduced muscle tone. Most patients have seizures, and some may have hydrocephalus.
Typically, treatment includes physical therapy, treatment for seizures, and, in cases that are complicated by hydrocephalus, a shunt to divert fluid. The prognosis for individuals with schizencephaly varies depending on the size of the clefts and the degree of neurological deficit.
schizophrenia The most common form of psychosis, affecting about one percent of the population, schizophrenia (or "fragmented mind") results in a break from reality involving bizarre delusions, illogical thinking, incoherence, and hallucinations. Schizophrenia also interferes with the ability to concentrate on and think about incoming information, but it is unclear to what extent this depends on the subtype of the disorder and to what extent it reflects the patient's problems with paying attention to outside events.
Originally termed dementia praecox by German psychiatrist Emil Kraepelin, the cause of schizophrenia has eluded researchers who have spent a great deal of time searching for evidence of physical dysfunction in the brains of schizophrenia patients.
It appears that schizophrenia may be caused by a malfunctioning dopamine system, and new research suggests that the roots of schizophrenia appear much earlier in brain development. In fact, considerable evidence suggests that malfunctioning fetal brain development may set the stage for later appearance of the disorder. It may be that aberrant organization of fetal brain cells during development may combine intact and impaired neurons together in dysfunctional circuits. Some researchers suggest that viral infections during pregnancy (together with other prenatal or birth problems) may play a role in the development not just of schizophrenia, but also of autism and dyslexia. As evidence, researchers cite a Finnish study that found a higher rate of schizophrenia among children of women exposed to a flu epidemic during the second trimester of pregnancy. Schizophrenia has also been linked to birth in the winter when viral infections are common.
Twin studies have also shown that some type of genetic mechanism strongly influences about half of all cases of schizophrenia.
Some researchers believe that many schizophrenia patients' brain development begins to break down in midpregnancy when many large neurons arrive at their final destination. In parts of the cor tex (the brain's outer layer) and within deeper regions associated with emotion and memory, researchers have found disorganized ensembles of neurons.
By staining schizophrenics' brains after autopsy, scientists have also found missing or abnormally sized neurons and abnormal myelination of nerve fibers.
People with both a family history of schizophrenia and a second trimester exposure to viral infection may experience the greatest chance of developing schizophrenia themselves. Minor complications at birth or shortly thereafter may boost these odds even further, scientists suggest. Other scientists suggest that families with high percentages of schizophrenia may lack the genetic instructions that guide cortical neurons during development to their final destination in circuit formation.
More recent research suggests that the root of schizophrenia may lie in abnormalities in the thalamus and related structures; scientists have already suspected that the thalamus helps focus attention and process sensory information. When comparing brains of normal and schizophrenic patients, researchers at the University of Iowa Hospitals and Clinics in Iowa City found that the area of greatest difference in strength of signal during magnetic resonance imaging (mri) was found in the thalamus and nearby tissue leading to the front of the cortex. schizophrenic men also had a much smaller thalamus than normal men.
Malfunctions in the underlying function of the thalamus, which develops before or shortly after birth, may be the root of the problem that underlies the various symptoms of schizophrenia.
Since the 1950s, doctors have used the phenoth-iazines (especially chloropromazine) to tame the symptoms of schizophrenia. More recently, haloperidol has also been helpful in controlling some of the most problematic symptoms; neither drug offers a complete cure.
Recent swiss research suggests that training to improve attention, memory and basic reasoning skills may play a role in treating many cases of the disease. Their approach of cognitive rehabilitation
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