Many people with Long COVID experience lingering neurological and psychological symptoms months after their initial infection. Commonly reported symptoms include fatigue, memory and concentration problems, sleep issues and muscle pain. Cases of depression, anxiety, and sensory disturbances like loss of taste and smell are also reported by many affected individuals.
A large cohort study including 236 379 COVID-19 survivors found that after six months, 34% of them had some form of neurological or psychiatric diagnosis. These findings underscore the significant long-term impact of COVID-19 on the brain and nervous system.
Many patients display symptoms that are not typically associated with a respiratory virus. Transcranial stimulation, a non-invasive therapy approach, could be beneficial to treat these symptoms in people affected by Long COVID.
Non-invasive brain stimulation in a nutshell
In the field of psychiatry, traditional treatments include medications like antidepressants, physical methods like electroconvulsive therapy (brief electrical stimulation of the brain) and psychotherapy such as cognitive behavioral therapy. These treatments can help the brain to rewire and promote the release of beneficial neurotransmitters. However, they might not work for everyone.
Over the past decade, new non-invasive brain stimulation methods have emerged, such as transcranial magnetic stimulation (TMS), transcranial pulse stimulation (TPS), or transcranial direct current stimulation (tDCS).
In brief these methods are non-invasive, advanced treatments that use electromagnetic stimuli to stimulate specific parts of the brain. This is a painless approach that might help people suffering from cognitive impairment due to conditions like Long COVID.
The three techniques mentioned, use different electromagnetic inputs. While TMS uses a magnetic field to stimulate the brain, TPS uses a pulsed electromagnetic field and tDCS a constant direct electrical current. The stimulation in the brain is different depending on the technique used.
TMS and TPS have an immediate but short-term effect on the brain and can reach deeper regions, while tDCS seems to have a more long-lasting effect. Moreover, the magnetic stimulation with TMS has a more localized effect on brain activity compared to techniques using an electrical current for stimulation (TPS and tDCS). All these techniques have shown beneficial effects on cognitive impairment in clinical studies.
Non-invasive brain stimulation methods have shown to be effective in neurological and psychiatric disorders
Transcranial pulse stimulation for example, has shown to improve cognition, memory, and depression in Alzheimer’s patients already over a short treatment period. It has been investigated as a potential treatment for various neurological disorders, including depression, Alzheimer's disease, Parkinson's disease, and autism spectrum disorder.
Transcranial magnetic stimulation has shown to be effective in treating neuropathic pain, motor stroke, and depression and can relieve symptoms in patients suffering from fibromyalgia, Parkinson’s disease, post-stroke aphasia, multiple sclerosis, and post-traumatic stress disorder according to the European recommendations (2020).
Similarly to TMS and TPS, transcranial direct current stimulation (tDCS) has been reported to be an effective treatment for several neurological and psychiatric disorders. Moreover, in people suffering from fatigue due to multiple sclerosis, a significant improvement of fatigue has been observed, making tDCS especially interesting for treating Long COVID.
As the technologies are still a new, more studies are needed to fully understand their effects on patients with neurological symptoms after coronavirus infection.
Non-invasive brain stimulation methods are currently being investigated in clinical trials for treatment of Long COVID patients with cognitive impairment
Several clinical trials are currently investigating the benefit of non-invasive brain stimulation methods for Long COVID patients suffering from cognitive and neurological symptoms or fatigue. However, clinical evidence on these interventions is still scarce. Still, a few case studies and real-world observations suggest a potential benefit.
A small real-world analysis in Japan, including 23 patients showed beneficial effects of TMS on depressive symptoms, chronic fatigue, and cognitive impairment caused by Long COVID.
Moreover, in a study on the effect of high-definition tDCS in 70 patients with Long COVID-related fatigue the treatment was able to reduce fatigue and anxiety symptoms and thereby improve quality of life of these patients.
Based on this, non-invasive brain stimulation represents a possible future trend in treating brain-related diseases and psychiatric symptoms. These methods could be especially useful for patients who have not responded to other treatments.
However, we need larger and more sophisticated studies for more conclusive results. In practice, the use of non-invasive brain stimulation methods is complex and demands knowledge in neuroscience and neurology. Therefore, only specialists can handle its application to ensure safety.
