Neurological disorders
What are neurological disorders and how many people are affected by them?
Neurological disorders are diseases of the central and peripheral nervous system. In other words, the brain, spinal cord, cranial nerves,
peripheral nerves, nerve roots, autonomic nervous system, neuromuscular junction, and muscles. These disorders include epilepsy, Alzheimer disease and other dementias, cerebrovascular diseases including stroke, migraine and other headache disorders, multiple sclerosis, Parkinsons disease, neuroinfections, brain tumours, traumatic disorders of the nervous system such as brain trauma, and neurological disorders as a result of malnutrition.
Mental disorders, on the other hand, are psychiatric illnesses or diseases which appear primarily as abnormalities of thought, feeling or behaviour, producing either distress or impairment of function.
Hundreds of millions of people worldwide are
affected by neurological disorders. Approximately 6.2 million people die because of stroke each year; over 80% of deaths take place in low- and middle-income countries.
More than 50 million people have epilepsy
worldwide. It is estimated that there are globally 35.6 million people with dementia with 7.7 million new cases every year - Alzheimers disease is the most common cause of dementia and may contribute to 6070% of cases. The prevalence of migraine is more than 10% worldwide.
Epilepsy
Epilepsy is a chronic disorder of the brain that affects people in every country of the world. It is characterized by recurrent seizures. Seizures are brief episodes of involuntary shaking which may involve a part of the body (partial) or the entire body (generalized) and sometimes accompanied by loss of consciousness and control of bowel or bladder function.
The episodes are a result of excessive electrical discharges in a group of brain cells. Different parts of the brain can be the site of such discharges. Seizures can vary from the briefest lapses of attention or muscle jerks, to severe and prolonged convulsions. Seizures can also vary in frequency, from less than one per year to several per day.
One seizure does not signal epilepsy (up to 10% of people worldwide have one seizure during their lifetimes). Epilepsy is defined by two or more unprovoked seizures. Epilepsy is one of the worlds oldest recognized conditions. Fear, misunderstanding, discrimination and social stigma have surrounded epilepsy for centuries. Some of the stigma continues today in many countries and can impact the quality of life for people with the disorder and their families.
Signs and symptoms
Characteristics of seizures vary and depend on where in the brain the disturbance first starts, and how far it spreads. Temporary symptoms can occur, such as loss of awareness or consciousness, and disturbances of movement, sensation (including vision, hearing and taste), mood or mental function.
People with seizures tend to have more physical problems (such as fractures and bruising), as well as higher rates of other diseases or psychosocial issues and conditions like anxiety and depression.
Rates of disease
The estimated proportion of the general population with active epilepsy (i.e. continuing seizures or the need for treatment) at a given time is between 4 to 10 per 1000 people. However, some studies in developing countries suggest that the proportion is between 6 to 10 per 1000. Around 50 million people in the world have epilepsy.
In developed countries, annual new cases are between 40 to 70 per 100 000 people in the general population. In developing countries, this figure is often close to twice as high due to the higher risk of experiencing conditions that can lead to permanent brain damage. Close to 80% of epilepsy cases worldwide are found in developing regions. The risk of premature death in people with epilepsy is two to three times higher than it is for the general population.
Causes
The most common type for six out of ten people with the disorder is called idiopathic epilepsy and has no identifiable cause. In many cases, there is an underlying genetic basis.
Epilepsy with a known cause is called secondary epilepsy, or symptomatic epilepsy. The causes of secondary (or symptomatic) epilepsy could be:
brain damage from prenatal or perinatal injuries (a loss of oxygen or trauma during birth, low birth weight);
congenital abnormalities or genetic conditions with associated brain malformations;
a severe blow to the head;
a stroke that starves the brain of oxygen;
an infection of the brain such as meningitis, encephalitis, neurocysticercosis;
certain genetic syndromes;
a brain tumor.
Treatment
Recent studies in both developed and developing countries have shown that up to 70% of newly diagnosed children and adults with epilepsy can be successfully treated (i.e. their seizures completely controlled) with anti-epileptic drugs (AEDs). After two to five years of successful treatment, drugs can be withdrawn in about 70% of children and 60% of adults without relapses.
In developing countries, three fourths of people with epilepsy may not receive the treatment they need.
About 9 out of 10 people with epilepsy in Africa go untreated.
In many low- and middle-income countries, there is low availability and AEDs are not affordable and this may act as a barrier to accessing treatment. A recent study found the average availability of generic antiepileptic medicines in the public sector to be less than 50%.
Surgical therapy might be beneficial to patients who respond poorly to drug treatments.
Prevention
Idiopathic epilepsy is not preventable. However, preventive measures can be applied to the known causes of secondary epilepsy.
Preventing head injury is the most effective way to prevent post-traumatic epilepsy.
Adequate perinatal care can reduce new cases of epilepsy caused by birth injury.
The use of drugs and other methods to lower the body temperature of a feverish child can reduce the chance of subsequent convulsions.
Central nervous system infections are common causes of epilepsy in tropical areas, where many developing countries are concentrated. Elimination of parasites in these environments and education on how to avoid infections would be effective ways to reduce epilepsy worldwide, for example due to neurocysticercosis.
Souce: WHO
