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Pain

Modern technology may help manage or even prevent pain before it becomes chronic. A recent study exploring the effects of repetitive transcranial magnetic stimulation (rTMS) on pain sensitivity offers some intriguing insights.

What is rTMS?

rTMS is a non-invasive method of brain stimulation. It involves sending magnetic pulses to specific areas of the brain through a coil placed on the scalp. This technique has been used to treat conditions like depression and chronic pain, but researchers are now looking at its potential to prevent pain. We used rTMS at the New York Headache Center to treat chronic migraine, other pain and neurological conditions that do not respond to usual treatment.

In a controlled experiment, researchers led by Nahian Chowdhury examined the role of rTMS in reducing future pain in healthy volunteers. The results were published in the latest issue of Pain, a journal of the International Association for the Study of Pain.

The subjects were divided into two groups:

Active rTMS Group: Received high-frequency rTMS to the area of the brain responsible for hand movements.

Sham rTMS Group: Received a fake treatment for comparison.

Both groups were then given an injection of nerve growth factor (NGF) into their jaw muscles, which causes prolonged pain similar to temporomandibular disorders (TMD), a condition causing jaw pain and dysfunction.

Results:

Pain Reduction: Participants who received active rTMS reported significantly less pain when chewing or yawning than the sham group. This effect was more pronounced in the early stages after the injection but persisted for days and weeks.

Brain Activity: The study found an increase in what’s known as peak alpha frequency (PAF) after rTMS, which is linked to lower pain sensitivity.

What Does This Mean for Pain Management?

Preventive Potential: This research suggests that rTMS could be used prophylactically to reduce pain sensitivity when pain is expected, like before surgery.

Future Directions: While promising, this study opens the door to further research into how rTMS can be optimized for pain control, potentially exploring different frequencies, duration, and areas of stimulation.

Pre-Surgery: rTMS might be used to reduce postoperative pain, potentially preventing the transition to chronic pain.

Chronic Pain Management: For those already dealing with chronic pain, understanding how brain activity changes with rTMS could lead to more effective treatments.

Conclusion

While we are still in the early stages, this study of rTMS offers hope for pain sufferers. It suggests a future where we might not only treat pain more effectively but also prevent it from becoming a long-term problem. This could revolutionize our approach to pain management, making it less about reducing and enduring pain and more about preventing it from taking root in the first place.

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Researchers at a hospital in Northern India reported good results in treating New Daily Persistent Headache (NDPH) with repetitive transcranial magnetic stimulation (rTMS).

NDPH is a type of headache that begins suddenly and persists daily without specific features, distinct MRI presentation, or blood test abnormalities. It can present similarly to chronic migraines or chronic tension-type headaches. While published reports suggest NDPH is difficult to treat, this is often not the case. However, patients who do not respond to initial standard treatments may become discouraged.

The Indian researchers conducted a pilot study with 50 NDPH patients who received 10 Hz rTMS sessions on the left prefrontal cortex of the brain for three consecutive days. They found that after 4 weeks:

  • 70% of patients had at least a 50% reduction in headache severity

  • Patients gained an average of 11 headache-free days per month

  • 76% had significant improvements in headache-related disability

  • Depression and anxiety scores also improved significantly

The treatment was well-tolerated, with only minor side effects in a few patients. The benefits seemed especially pronounced in patients who had NDPH that resembled chronic migraine.

I never give the diagnosis of NDPH, but diagnose it as a condition it most resembles and treat the person with a wide variety of available options. Many respond. For those who do not, we offer rTMS, a procedure that uses magnetic fields to stimulate nerve cells in the brain. An electromagnetic coil device is placed against the scalp near the forehead. The coil painlessly delivers a magnetic pulse that stimulates the brain with the goal of reducing headache symptoms. The FDA has approved it for the treatment of depression, anxiety, and OCD. We use it for various neurological conditions, including headaches that do not respond to standard therapies. To treat migraines and other types of pain, we usually stimulate not only the left prefrontal cortex, as was done in this study, but also two additional sites that have been reported to help with pain and migraines. These additional sites are either the motor cortex or the occipital cortex, on both sides.

Sometimes, we obtain a functional magnetic resonance imaging (fMRI) scan to better target rTMS. fMRI is a research procedure that is not available commercially (and is not covered by insurance).

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Chronic pain is known to alter the brain’s default mode network (DMN). The DMN is a group of interconnected brain regions activated when a person is not focused on the external world. Key DMN functions include mind wandering (daydreaming, thinking about the past or future, imagining scenarios), self-reflection (considering thoughts, feelings, and experiences), theory of mind (understanding others’ thoughts and intentions), and memory (retrieval and processing).

A recent study published in the journal Pain by German researchers investigated the relationship between chronic back pain and DMN alterations. The study, titled “Beyond the chronic pain stage: default mode network perturbation depends on years lived with back pain,” examined patients with chronic back pain (CBP), subacute back pain (SBP), and healthy controls using fMRI.

Results showed that the DMN is significantly altered in CBP patients compared to healthy individuals. Importantly, the degree of DMN disruption increased with the duration of pain, suggesting that the brain adapts to persistent pain over time. This adaptation is influenced by cognitive coping strategies or how individuals mentally manage their pain.

The study found that coping attitudes mediate the link between DMN changes and pain duration. This implies that how people think about and handle pain impacts their brain’s adaptation to it. Effective pain coping strategies could potentially lessen the negative effects of chronic pain on the brain, emphasizing the importance of psychological interventions like meditation, cognitive behavioral therapy (CBT), and acceptance-commitment therapy (ACT).

These findings also provide a scientific basis for treatments like transcranial magnetic stimulation (TMS) and other brain stimulation methods, which aim to restore normal brain connectivity, including DMN function.

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The use of focused ultrasound to treat brain disorders was one of the topics discussed at the 2024 NYC Neuromodulation Conference in NYC.

Coincidentally, a study on this topic was published last month by Jan Kubanek and his colleagues in Pain, the journal of the International Association for the Study of Pain: “Noninvasive targeted modulation of pain circuits with focused ultrasonic waves”.

Researchers developed a technique that targets the anterior cingulate cortex, a deep brain region involved in processing pain. By using focused ultrasound, this region can be modulated without surgery. This breakthrough has the potential to revolutionize pain management.

Twenty patients with chronic pain participated in a randomized crossover trial. They received two 40-minute sessions of either active or sham stimulation and were monitored for one week. The results were remarkable:

  • 60% of patients experienced a significant reduction in pain on day 1 and day 7 after active stimulation.
  • Sham stimulation only benefited 15% and 20% of patients, respectively.
  • Active stimulation reduced pain by 60.0% immediately after the intervention and by 43.0% and 33.0% on days 1 and 7.
  • Sham stimulation only reduced pain by 14.4%, 12.3%, and 6.6% on the same days.

The stimulation was well tolerated and the side effects were mild and resolved within 24 hours.

Since we have been using transcranial magnetic stimulation (TMS) to treat refractory migraines and other neurological conditions, it was good to read this part of the authors’ conclusion:

“The ultrasonic intervention is conceptually related to TMS applied to the motor cortex, which can provide improvements in chronic pain in certain groups of patients. The key difference is that ultrasonic waves can directly modulate the deep brain regions involved in chronic pain, including the anterior cingulate cortex. Transcranial magnetic stimulation is believed to modulate deep brain regions only indirectly, which may contribute to its variable response and the need for frequent re-administrations. Nonetheless, the effects of both modalities may be complementary, and their combined application may provide stronger effects than either approach alone.”

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Functional MRI (fMRI) studies have shown that people with migraines have altered functional connectivity and activation patterns in pain-processing brain regions like the insula, thalamus, somatosensory cortex, as well as visual cortex. Some patients also have changes in the default mode and salience networks involved in attention and stimulus processing.

A study published this month by Chinese researchers in the Journal of Headache and Pain reports on connectivity changes in people with vestibular migraines.

They found abnormal resting-state functional connectivity in brain regions involved in multi-sensory and autonomic processing as well as impaired ocular motor control, pain modulation, and emotional regulation.

Until now, there has been little practical application for fMRI findings. However, with the help of Omniscient Neurotechnology, we have just started using fMRI data to better target our treatment with transcranial magnetic stimulation (TMS). TMS applied to motor and visual cortices has been reported to help relieve migraine headaches. We have also found it effective in a significant proportion of patients who did not respond to various other treatments. We have not yet accumulated enough data to determine if fMRI-guided TMS treatment is superior to TMS administered over a predetermined set of targets.

The main obstacle to wider use of TMS in clinical practice is the cost. TMS is approved by the FDA and is covered by insurance for the treatment of anxiety and depression, but not migraines or pain. fMRI is an expensive research tool and is also not covered by insurance. Hopefully, the NIH and other research foundations will provide the funds needed to study this promising treatment.

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Nolan Williams has been at the forefront of developing breakthrough TMS protocols for the treatment of depression and other psychiatric indications. It was very stimulating and informative to discuss techniques, protocols, indications, and research into TMS for various neurological and psychiatric indications with the members of Nolan Williams’ lab Greg Sahlem and Ika Kaloiani. Thank you for sharing your knowledge.

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Repetitive transcranial magnetic stimulation (rTMS) is approved by the FDA for the treatment of depression and anxiety. We have been using it to treat migraine headaches and other neurological conditions that are not responsive to standard therapies. Improvement in headaches and pain may be at least in part due to improvement in depression. However, additional mechanisms play a role since we see patients who are not depressed but whose pain improves with rTMS.

A new study by Chinese and Australian researchers published in Pain suggests that opioid mechanisms (endorphins, encephalin, and other peptides) may underlie the mechanism of pain relief produced by rTMS.

This was a double-blind, placebo-controlled study. 45 healthy participants were randomized into 3 groups: one receiving rTMS over the primary motor cortex (M), dorsolateral prefrontal cortex (DLPFC), or sham stimulation. Experimental pain was induced by applying capsaicin (hot pepper extract) over the skin of the right hand followed by application of heat.

Participants received intravenous naloxone (an opioid receptor antagonist) or saline before the first rTMS session to block or allow opioid effects, respectively. After 90 minutes to allow naloxone metabolism, participants received a second rTMS session.

For the M1 group, naloxone abolished the analgesic effects of the first rTMS session compared to saline. Pain relief returned in the second session after naloxone was washed out of the body. For the DLPFC group, only the second prolonged rTMS session induced significant analgesia in the saline condition compared to naloxone. rTMS over M1 selectively increased plasma ?-endorphin levels, while rTMS over DLPFC increased encephalin levels.

The results suggest that opioid mechanisms mediate rTMS-induced analgesia. The specific opioid peptides and rTMS dosage requirements differ between M1 and DLPFC stimulation.

However, these results are far from definitive. The study was small and the study protocol was complicated (e.g. using a double dose of rTMS to DLPFC), which increases the likelihood of an error. Also, these results apply to conditions of acute pain. In patients with chronic pain and headaches, rTMS likely provides relief by improving network connectivity between different parts of the brain.

 

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We use a neuronavigation system from Soterix (on the left) for precise targeting of transcranial magnetic stimulation (TMS). And we use the most advanced TMS machine from MagVenture (on the right) to treat chronic pain, migraines, fibromyalgia, and other neurological conditions.

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Medication overuse or rebound headaches can occur as the result of excessive intake of caffeine, opioid analgesics, and short-acting barbiturate drug, butalbital (contained in Fioricet, Esgic and similar drugs). These three substances not only worsen migraine headaches, they are also addictive.  Two of my patients with medication overuse headaches were able to stop the offending drugs with the help of repetitive transcranial magnetic stimulation (rTMS).

One patient, a 51-year-old man, had his migraines under control with Botox and infusions of eptinezumab (Vyepti) until he sustained a head injury with a skull fracture. His migraines worsened and he became disabled. A variety of therapies failed to reduce his pain. His pain was partially relieved by 60 mg of oxycodone a day, although he still was unable to work. After six weekly sessions of rTMS he was able to start reducing his oxycodone intake and after eight, he completely stopped it. He was able to return to work with the help of injections of fremanezumab (Ajovy).

Another patient, a 50-year-old woman, had been taking butalbital with caffeine and acetaminophen (Fioricet) for 20 years. The number of pills increased over time and for the previous several years, she had been taking 10 to 12 tablets every day. She was also receiving Botox injections, infusions of eptinezumab, and taking rizatriptan (Maxalt), 10 mg three times a day as well as 60 mg of nortriptyline, 12 mg of tizanidine nightly and atogepant, 60 mg. She had tried a wide variety of other treatments but was unable to reduce her Fioricet intake. Despite her persistent migraines, she was able to take care of her family. After three weekly sessions of rTMS she reduced her Fioricet intake to 3-4 a day, by the third month she was taking one a day, and after 6 months she was completely off it. She was also able to stop atogepant and tizanidine and reduced her nortriptyline to 25 mg.

In addition to helping relieve pain and migraines, rTMS has shown promise in the treatment of addiction, particularly in addressing withdrawal symptoms, depression, and cravings. While the use of rTMS for addiction is still relatively recent and not yet FDA-approved, some studies have demonstrated positive outcomes. For instance, a double-blind study showed that individuals receiving rTMS therapy for cocaine addiction had a higher rate of abstinence compared to those who received standard treatment. rTMS for addiction is still considered experimental, and more research is needed to fully understand its long-term effects and optimal treatment parameters.

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Neurologists frequently find themselves managing patients resistant to standard treatments due to limited proven therapies for many neurological conditions. Some patients cannot tolerate or have contraindications to medications, particularly for such common disabling conditions like migraine and chronic pain. 

One promising treatment is transcranial magnetic stimulation (TMS). It is a proven procedure for anxiety, depression, obsessive-compulsive disorder (OCD), smoking cessation, and acute migraines. TMS utilizes magnetic fields to stimulate nerve cells in the brain that are underactive or reduce the excitability of overactive cells. TMS can change the flow of information between different parts of the brain in various neurological conditions. Published reports show the potential benefit of TMS in fibromyalgia, neuropathic pain, cluster headaches, facial pain, trigeminal and other neuralgias, back pain, insomnia, memory disorders, tinnitus, post-concussion syndrome, post-traumatic stress disorder (PTSD), restless leg syndrome, and long COVID. The evidence for the efficacy of TMS for these neurological disorders, however, is still limited.

Single-pulse TMS is approved by the FDA for the acute treatment of migraines with aura. The patient uses a portable device during the aura phase to self-administer a single pulse of TMS to the back of the head. This can abort the attack. Repetitive TMS (rTMS) has been studied for the prevention of migraines and other types of pain. It appears effective, but compared to depression trials, migraine studies were relatively small and the FDA has not cleared rTMS for the treatment of migraines. This means that insurance companies are not likely to pay for this “off-label” use of TMS.

rTMS is generally considered safe and well-tolerated, with side effects typically mild and temporary, including scalp discomfort, headaches, and facial twitching. More serious side effects like seizures and mania are very rare. 

Before starting TMS, patients undergo a physical and mental health evaluation. The coil placement and dose are determined in the first session. During a TMS session, patients sit in a comfortable chair with earplugs. An electromagnetic coil is positioned near the scalp, delivering short magnetic pulses to specific brain regions involved in processing pain and other information. Patients feel and hear rapid tapping on their scalp that continues, on and off. Patients are awake and alert during the entire procedure. There are no limitations to activities before or after the treatment.

Treatment length varies from 20 to 45 minutes, depending on the stimulation pattern and number of sites stimulated. The frequency of treatments also varies – anywhere from daily for several weeks, to once a week. After the initial period of more frequent sessions, some patients require weekly or monthly sessions to maintain the effect. It may take a few weeks to see noticeable effects. 

TMS is a good choice for people who have not responded to multiple standard therapies, people who do not want to take drugs, those who also suffer from depression and anxiety, and pregnant women. Sufficient evidence suggests that TMS is as safe in children as it is in adults, with studies indicating its effectiveness in treating depression in adolescents.

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Neurologists diagnose migraine by the description of symptoms provided by the patient. We have not had an objective test to confirm that a person suffers from migraines.

A group of researchers led by Dr. Yiheng Tu in the department of psychiatry at Harvard Medical School developed an AI program that can diagnose migraine using fMRI (functional MRI) scanning. The AI program was first fed information on fMRIs of 116 individuals with migraines and then had this data compared to healthy controls.

The AI program had 93% sensitivity and 89% specificity. This means that it missed the diagnosis of migraine in only 7 out of 1oo patients and diagnosed migraine in 11% of patients who did not have it. These are very good numbers, but clearly, the method is not error-proof.

When they compared people with migraines to those with other types of pain, the sensitivity dropped to 78% and specificity, to 76%. This can be explained by the fact that similar functional changes in the brain probably occur with any type of pain.

A major obstacle to the wide use of fMRI scans is the cost. They are more expensive to perform than a regular MRI. Insurance companies are not likely to cover it since this is an experimental procedure. Another potential difficulty is that fMRI takes much longer to do than a regular MRI – an hour vs 20 minutes. During this time you have to lie inside a tube while trying not to move and hearing loud banging noises.

 

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Our thoughts and emotions can impact the development of chronic pain. However, there haven’t been many studies exploring what causes pain to transition from being short-term (acute) to long-lasting (chronic).

Australian researchers conducted a study to investigate how our thought patterns, anxiety related to pain, and the tendency to avoid pain affect both acute and chronic pain. They conducted two studies for this purpose. In the first study, they interviewed 85 individuals experiencing long-term pain to understand their thoughts and emotions. In the second study, they observed 254 individuals who had recently started experiencing acute pain and followed up with them three months later.

In both studies, they examined interpretation bias using a word association task and assessed pain-related anxiety, pain avoidance, pain intensity, and how pain interfered with daily life. In both cases, they discovered that the way people think about pain was linked to how much it disrupted their daily lives. In the second study, they also found that people’s thought patterns about pain were connected to increased anxiety about pain. This heightened anxiety, in turn, made the pain more severe and disruptive after three months. While anxiety about pain also led people to try to avoid it, this avoidance behavior didn’t seem to affect the level of pain they experienced later on.

This research provides valuable insights into how pain can transition from acute to chronic. It suggests that our initial thoughts about pain might trigger anxiety related to pain, which can contribute to the pain persisting and becoming more troublesome over time. This finding could be crucial in developing strategies to prevent chronification of pain by addressing how people perceive and manage their anxiety about pain during its early stages. Cognitive-behavioral therapy, meditation, and other mind-body techniques could be some of such strategies.

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