World Movement Disorders Day 2022: What Are These Neurological Disorders And Why They Are Difficult To Identify, Treat

Movement disorders constitute three to eight per cent of all neurological disorders in India. Tremors are one of the most common types of movement disorders.

Parkinson's disease and essential tremors typically begin in the sixth decade of life. (Representative Photo) ( Image Source :Getty )

By Dr Sanjay Pandey

Movement disorders are complex. These are movement-related issues that are challenging to identify and treat. They constitute three to eight per cent of all neurological disorders in India, with the crude prevalence rate ranging from 31 to 45 per 1 lakh persons aged above 60 years.

Tremors are one of the most common types of movement disorders, characterised by involuntary, rhythmic muscle contractions that result in shaking or trembling movements in one or more parts of the body. These mainly affect the hands, but can also be found in the arms, head, vocal cords, torso, or legs. 

Tremors can be very mild at times and even go unnoticed during examinations by the doctor. If the symptoms are moderate or severe, patients usually face difficulty in writing, typing, eating, drinking, or driving.

Tremors are of two types: rest and action tremors. In the former, a person's limbs such as hands or fingers may shake or tremble even when they are at rest and the muscle is relaxed. The most common cause of rest tremors is Parkinson’s disease, with its crude prevalence rate ranging from six to 40 per 10,000 people.

Action tremors, on the other hand, refer to tremors produced while doing any activity that entails voluntary muscle contraction. These can be postural (occurring during a posture maintained against the force of gravity, such as when arms are extended in front), kinetic (occurring during voluntary movement of a body part, such as moving wrists up and down), and task-specific (such as during writing or shaving). 

Essential tremor (ET) is the most common cause of postural tremors involving involuntary and rhythmic shaking. It most often affects the hands. Some amount of tremor is present in every individual. In stressful situations, this tremor worsens and is known as enhanced physiological tremor (EPT). 

Tremors can appear at any age. Parkinson's disease and essential tremors typically begin in the sixth decade of life. But, in the familial type of Parkinson’s disease, enhanced physiological tremors may appear at a younger age.

Tremors in older patients are commonly assumed to happen naturally due to advancing age, and treatment is not sought. Due to this, the diagnosis of many diseases like Parkinson’s gets delayed in patients. If a tremor is disabling or associated with the slowness of body movement, rigidity, or dystonia (involuntary muscle contraction), one should immediately get it checked by a doctor. Most of the tremors can be controlled by medications, such as botulinum toxin injections, deep brain stimulation, and MRI-guided focused ultrasound.

With increasing life expectancy in India and improved diagnostics, the incidence of movement disorders is also seeing a rise, as Parkinson’s and essential tremors are mostly found in the age group of 60-plus years. 

Dystonia, chorea, and tics are other movement disorders that are frequently seen in the community. Dystonia may affect one body part or may be generalised. A writer’s cramp is a unique type of dystonia where patients have difficulty in writing. Sydenham chorea is commonly seen in children, whereas Huntington’s disease is a frequent cause of chorea in adults. Tics are commonly observed in the paediatric population, but rarely can be seen in adults also. 

There are very few professionals in India trained in identifying and treating movement disorders. The majority of Indian doctors still have to travel abroad to study these disorders. There is an urgent need to develop more training centres for movement disorder professionals in India.

The author is the Head of the Department of Neurology at Amrita Hospital, Faridabad.