Stroke - On the horizon

Several new therapies are emerging for the treatment of stroke. Many of these focus on improved rehabilitationThe treatment of a person with an illness or disability to improve their function and health., and on helping people to recover their motorRelating to the part of the nervous system that carries information from the brain and spinal cord to cause activity in a muscle or gland. and sensory functions.

Important recent research suggests that the window of time available for people to recover function after they've had a stroke is much longer than was previously thought.

With an arsenal of new rehabilitationThe treatment of a person with an illness or disability to improve their function and health. techniques, the recovery of all or most of their motorRelating to the part of the nervous system that carries information from the brain and spinal cord to cause activity in a muscle or gland. and sensory function after a stroke may be a reality for more people than ever before.

These pages will discuss the following techniques:

Rehabilitation pharmacology

What is it?

Rehabilitation pharmacology is the use of certain medicines to improve function after a stroke. The two medicines that are considered to have the most potential for this purpose (and are therefore the most widely studied) are amphetamine and levodopa.[1] It is important to note, though, that these medicines are still experimental and further research into their benefits and proper use is needed; abuse of amphetamines, for example, can actually increase the risk of haemorrhagic stroke.

How does it work?

Studies suggest that amphetamine may improve recovery after a stroke because it increases the release of neurotransmitters, chemicals that enable nerveBundle of fibres that carries information in the form of electrical impulses. cells (neurons) to send messages to each other.[1]

Levodopa is converted to dopamineA type of neurotransmitter - chemicals that help the communication between nerve cells (neurons). - a type of neurotransmitterA chemical that helps the communication between nerve cells (neurons). - in the brain. It is thought that increased levels of dopamineA type of neurotransmitter - chemicals that help the communication between nerve cells (neurons). may enhance memory, and help the person to remember basic motorRelating to the part of the nervous system that carries information from the brain and spinal cord to cause activity in a muscle or gland. skills in particular.[1]

Who is it for?

Rehabilitation pharmacology is aimed at people who are undergoing rehabilitationThe treatment of a person with an illness or disability to improve their function and health. for a stroke, who may benefit from additional intervention.

What stage of development has been reached?

Larger studies are needed to justify the use of both amphetamines and levodopa. Amphetamine has been shown to be safe in clinical studies, but because these studies were quite small it is not yet clear how effective it is.[1]

Repetitive transcranial magnetic stimulation

What is it?

Repetitive transcranial magnetic stimulation (rTMS) is a completely non-invasiveAny test or technique that does not involve penetration of the skin. The term 'non-invasive' may also describe tumours that do not invade surrounding tissues. therapy that modulates activity in a part of the brain called the cortexThe outer region of an organ.. A magnetic field is generated by an electric current passed through a copper coil, which is held near the head. After a stroke, activity in the part of the brain that controls the weakened muscles is reduced - while activity in the unaffected part of the brain may be increased. The use of rTMS may enhance activity in the affected cortexThe outer region of an organ..[5]

How does it work?

After a stroke, it is believed that reduced activity in the cortexThe outer region of an organ. of the affected side of the brain leads to reduced strength in the muscles controlled by that part of the brain. Stimulating activity in the affected part of the brain with rTMS may lead to better recovery of movement after a stroke.[1]

Who is it for?

People who are experiencing weakness or paralysis after a stroke.[1]

What stage of development has been reached?

Used in conjunction with motorRelating to the part of the nervous system that carries information from the brain and spinal cord to cause activity in a muscle or gland. exercises, rTMS appears to have some beneficial effects. However, further research is needed, and there is still work to be done to determine the optimal number of treatment sessions and other such variables.[1]

Robot-assisted motor rehabilitation

What is it?

This type of treatment uses interactive robotic devices to aid in rehabilitationThe treatment of a person with an illness or disability to improve their function and health. after a stroke Any sudden neurological problem caused by a bleed or a clot in a blood vessel. - most often, in the recovery of arm movement.[1]

How does it work?

One example developed involves placing the weak arm into a brace, which is itself attached to the arm of a robot. As a physiotherapistA healh professional who specialises in physical therapies, such as exercise, massage and manipulation. guides the patient through the exercises, the robot records the session. After this, the robot can reproduce the exercise and guide the person's arm through these motions. The robot can actually adjust the amount of resistanceThe ability of a microbe, such as a type of bacteria, to resist the effects of antibiotics or other drugs. to movement, according to the force the patient is applying.[1]

Compared with exercises led by a physiotherapistA healh professional who specialises in physical therapies, such as exercise, massage and manipulation., interactive robotic devices have the ability to deliver controlled, reproducible movements as well as to assess how well the patient is responding.[1,3]

Who is it for?

This therapy is designed for people who have a degree of weakness or paralysis following a stroke, particularly those who have weakness in one of their arms.[1]

What stage of development has been reached?

Research in this area has been very encouraging, but larger studies are still needed before robot-assisted therapy can become a standard treatment.[1,3]

Constraint-induced movement therapy

What is it?

Constraint-induced movement therapy (CIMT) is a type of rehabilitationThe treatment of a person with an illness or disability to improve their function and health. therapy for people who have weakness on one side of their body. It involves restricting movement in the arm that has normal ability, so that the person is obliged to try to use the affected arm.[4] This restriction is continued for a matter of weeks, using either a glove with a special arm rest or a restraining mitt.[1,4]

How does it work?

It is thought that CIMT encourages a person who has weakness in one arm to use that arm, either during exercise sessions or simply as they go about their daily activities. This leads to increased practice with the affected arm.[4]

The underlying rationale for CIMT is a theory called 'learned non-use'. This assumes that there may actually be a greater degree of ability in the affected arm than there at first appears, and that part of the explanation for the limited use is behavioural.[4] For example, initial difficulty in using the affected arm may discourage a person from using that arm in the future.

Who is it for?

CIMT is designed for people who have weakness along one side of their body following a stroke. It is not yet known which specific groups of people would be more likely to respond to this therapy.[4]

What stage of development has been reached?

Although benefits have been demonstrated, many studies of CIMT have been too small to show a clear effect. It is not yet known whether any improvements are maintained in the long term; further studies are needed.[4]

References: 
  1. Young S and He Kong K. Emerging therapies in stroke rehabilitationThe treatment of a person with an illness or disability to improve their function and health.. Ann Acad Med Singapore 2007; 36: 58-61.
  2. Kim YH, You SH, Ko MH et al. Repetitive transcranial magnetic stimulation-induced corticomotor excitability and associated motorRelating to the part of the nervous system that carries information from the brain and spinal cord to cause activity in a muscle or gland. skill acquisition in chronicA disease of long duration generally involving slow changes. stroke. Stroke 2006; 37: 1471-6.
  3. Volpe BT, Huerta PT, Zipse JL et al. Robotic devices as therapeutic and diagnostic tools for stroke recovery. Arch Neurol 2009; 66: 1086-90.
  4. Sirtori V, Corbetta D, Moja L et al. Constraint-induced movement therapy for upper extremities in stroke patients (Review). The Cochrane Library 2009; Issue 4.