What is a stroke?
A stroke is an interruption of the blood supply to the brain. It can be caused by either a blockage (an ischaemic stroke) or a haemorrhage (a haemorrhagic stroke). Symptoms can include motor problems (hemiplegia, hemiparesis), loss of vision, language problems, mental confusion, etc.
Consequently, strokes can cause permanent brain damage or even be fatal. Risk factors include age, high blood pressure, smoking, diabetes and heart disease. Prevention and early treatment are essential to minimise the damage caused by a stroke.
What are the most common after-effects of a stroke?
The most common sequelae of a stroke vary depending on the area of the brain affected by the interruption of the blood supply.
Some of the most common consequences include:
- Paralysis or weakness on one side of the body: this may affect the ability to walk, move arms or legs, or control fine movements.
- Impaired speech or understanding: this can make it difficult to communicate with others.
- Vision problems: this can cause vision disturbances, such as areas of darkness or loss of vision in one eye.
- Fatigue: people with stroke may feel very tired, even after a short period of activity.
- Memory and thinking problems: people with stroke may have difficulty remembering recent events, planning or solving problems.
- Emotional problems: people with stroke may experience anxiety, depression, irritability or mood swings.
Each person may have a different combination of effects and the extent of the effects will also vary from person to person. Rehabilitation, therapy and support can help people with stroke to improve their quality of life.
What does Transcranial Magnetic Stimulation bring to motor rehabilitation of the upper limb?
Stroke can cause paralysis or weakness in the arms, making it difficult to perform simple tasks such as combing hair, brushing teeth or dressing. Transcranial Magnetic Stimulation TMS has been used to improve motor recovery in the upper limb after a stroke. The effect of TMS is a clinically significant improvement in disability in patients with hemiparesis, increasing the ability to control the movements of the affected arms.
There are several potential benefits of using TMS to improve motor recovery in the upper limb:
- It can increase brain activation in damaged areas, which can improve the ability to control affected movements
- It can improve brain plasticity, which is the brain's ability to remodel its circuitry to compensate for the damage caused by the stroke
- It can help reduce the fatigue and pain associated with rehabilitation.
When applied at low frequency to the contralesional motor cortex during the post-acute period (between one week and six months post-stroke), transcranial magnetic stimulation (TMS) has been shown to be effective in promoting rehabilitation and improving residual motor function, at least in the hand. These beneficial effects were mainly observed when TMS was used as a priming method prior to 30-60 minutes of physiotherapy training and may persist for up to 6 months after the intervention1 .
Aphasia and language disorders
Transcranial Magnetic Stimulation rTMS is recommended for patients with language disorders in the chronic phase of stroke2 .
Most studies have evaluated the effectiveness of TMS for the rehabilitation of non-fluent aphasia, in which Broca's area is damaged by a middle cerebral artery infarct.
TMS is then usually applied at low frequency to the right cerebral hemisphere, i.e. opposite the damaged brain area. You need Neuronavigation to target the cortical area pars triangularis, which is the triangular part of the inferior frontal gyrus facing the anterior part of the lateral sulcus (Brodmann area BA45). The neighbouring target pars opercularis (BA44) has also sometimes been used successfully.
The aim of these stimulations is always the same, to down-regulate increased cortical activity in the contralesional hemisphere, thus reducing interhemispheric inhibition on the injured cortical regions, which is thought to interfere with successful language recovery.
These sessions are immediately followed by re-education exercises (speech therapy).
- 1 Lefaucheur JP, Aleman A, Baeken C, et al. Evidence-based guidelines on the therapeutic use of repetitive transcranial magnetic stimulation (rTMS): An update (2014-2018). Clin Neurophysiol. 2020;131(2):474-528, doi:10.1016/j.clinph.2019.11.002
2 Arheix-Parras S, Barrios C, Python G, et al. A systematic review of repetitive transcranial magnetic stimulation in aphasia rehabilitation: Leads for future studies. Neurosci Biobehav Rev. 2021;127:212-241. doi:10.1016/j.neubiorev.2021.04.008