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PhysioFunction discuss chronic pain and non-pharma means of intervention

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PhysioFunction discuss a non-pharmacological approach to the management of neuropathic and chronic pain and means of achieving results

Acute Pain

 Evolution has served us well with our immediate response to noxious stimuli or injury. Flexor withdrawal will result in us taking our hand away from a hot object, even before our conscious brain has registered the risk of a burn. An acute injury, for example an ankle strain, will result in swelling and pain inhibition to discourage extended weight-bearing causing further trauma to the affected tissues.

“The body’s response to acute injury is helpful –  like a home security alarm scaring off a would-be burglar and alerting the householder and neighbours to the risk.”

Chronic Pain

Lingering pain is operationally defined as “Chronic Pain” in the International Classification of Diseases (ICD) of the World Health as “persistent pain lasting for more than three to six months”. When the sensation of pain persists beyond the resolution of the original trauma (or surgery or inflammatory condition), it is termed Secondary Chronic pain. Chronic pain that has no apparent cause is termed Primary Chronic Pain. An example of this Neuropathic pain following spinal cord injury.

 Chronic pain is a leading cause of disability worldwide. 20 – 40 per cent of the population are estimated to experience some form of chronic pain.  Meta-analysis indicates that up to 67 per cent of individuals experience neuropathic pain following a Spinal Cord Injury (SCI), with up to 27  per cent at the level of their injury and up to 35 per cent below the injury level. 

“Chronic Pain is NOT helpful –  like a home security alarm continuing to sound long after the would-be burglar has fled the scene, and becoming a source of annoyance to the householder and their neighbours.” 

There are challenges to treating and managing Chronic Pain. Many pharmacological treatment strategies are far from optimal and are frequently associated with unwanted side-effects as well as a risk of dependence, misuse, and the development of tolerance. Non-pharmacological treatments including manual therapy, TNS, acupuncture, supervised exercise programs, and cognitive behavioural therapy (CBT) vary in their effectiveness and accessibility to those seeking resolution of pain.

Electroencephalographic Neurofeedback 

All our thoughts, emotions and perceptions including pain awareness are brought to our conscious mind via the electrical pulses of masses of cortical neurons communicating with each other – brainwaves. These brainwaves can be recorded using Electroencephalography (EEG) and classified into bands according to their frequency. Distinct patterns of activity have been identified that reflect the differential resting state activity in chronic pain sufferers. Individuals with chronic pain often exhibit suppressed EEG activity in the alpha frequency range (8-13 Hz), abnormal activity in the theta (4-8 Hz) and increased activity in hi-beta (13-30 Hz) frequency bands. 

Electroencephalographic neurofeedback (EEG neurofeedback) is a non-invasive neuromodulation method that enables unconscious processes to become observable, allowing a person to consciously interact with their own brain activity in real time. EEG neurofeedback can facilitate self-regulation of EEG activity in areas of the brain associated with a particular disease, such as chronic pain, applying the principles of operant conditioning in order to facilitate neuroplastic learning. 

This is not a new concept in the treatment of Chronic Pain. However, EEG neurofeedback equipment has historically required a large initial capital expenditure, and highly trained clinicians to administer and supervise the training. It has not been commercially available for home-management. Depending on the clinical aim of the training, individuals have been required to attend hospitals or clinics on an outpatient basis up to five times a week for two to three months, which is not practicable or affordable in the private sector for many of those suffering from chronic pain.

With a security alarm, we can turn disconnect the speaker or rewire the alarm circuit so that it is no longer registering a break in the circuit. Can individuals rewire their brains to reduce or eliminate the intrusive and troubling ain sensations arising from Chronic Pain?

The patterns of activity can be imagined as being like the frequencies on a graphic equalizer displayed on audio equipment.

Chronic pain is like the annoying bass boom coming from the speakers of a “car enthusiast” when we are traversing a pedestrian crossing. 

The frequency bands of brain waves exhibit near constant spontaneous fluctuation – like the bars on a graphic equaliser displaying the differing frequencies within the music being played. 

Imagine if our “car enthusiast” accidently tuning to Radio 2 and treating us to melodies of Taylor Swift / (insert tuneful artist of your choice), how much more pleasant our crossing would be. Can individuals change the array of maladapted  frequency bandings in their brains that are contributing to the maintenance of their ongoing symptoms?

Exsurgo and AXONTM

Exsurgo is a New Zealand medical technology company founded by Richard Little, the inventor of the REX exoskeleton. Having explored using EEG to control the movement of the REX, he saw the potential of EEG neurofeedback for the treatment and management of chronic pain. He recognised the challenge posed by the commercially available equipment used to deliver the training.

 The Research and Development team at Exsurgo developed a prototype EEG headset that could record signals from the scalp over the area of brain associated with the conscious awareness of pain.. They co-developed a tablet-based software application (App) to receive the signals via a Bluetooth connection and facilitate neurofeedback training by allowing the user to engage in “games” for example completing a virtual jigsaw or enabling a balloon to ascend on the screen. Progress within in a game is the reward for the spontaneous upregulation of the Alpha activity above the threshold set at the start of the treatment session. 

The AXON headset and tablet

Screenshot of one of the neurofeedback ‘games’, in which the user completes a virtual jigsaw. The individual is rewarded with the placement of a new place in response to their spontaneous upregulation of alpha activity

Many will be familiar with the concept and practice of operant conditioning, which is based on reward individuals or animals when the perform a desired behaviour – for example, teaching a dog to sit to command by them rewarding with treats for their spontaneous sitting behaviour.

WHEN subconscious behaviours or automimic states are consistently rewarded, the learning mechanisms within the brain seek to learn the associated and rewire accordingly. This is the basis also of PTSD when the brain learns to pattern match to a situation similar to a one-time traumatic event, for example flash-backs occurring long after an accident.

PhysioFunction was chosen by Exsurgo as their UK partner to run a Proof of Concept trial to assess the efficacy and AXON as a home-based NFB device for managing chronic pain by modifying specific EEG activity. 

The study was conducted between June 2020 and March 2021. 16 adults with chronic pain were enrolled into the trial and  were provided Axon EEG NFB systems for home use. Each participant  completed between 32 and 48 training sessions over eight to twelve weeks. 

The results were as follows:

  • 11 reported pain relief following NFB training
  • 8  reported clinically significant improvements that lasted at least until the 12-week follow-up.
  • 12 participants reported improvements in measures for Quality of Life (QoL),  including sleep.
  • More than 25 per cent of the participants requested continued access to the systems
  • Improvements were seen in measures for depression and anxiety.

A larger trial (n=116) has recently been completed in New Zealand. Preliminary results appear to have replicated the results of the PoC trial and strongly suggest that home-based NFB training may provide significant relief for sufferers of chronic pain and its associated symptoms.

The AXON 2.0 NFB system will be released commercially in November 2023. 

Exsurgo will be exhibiting at Therapy Expo on November 22 and 23, TG33, Birmingham NEC

References:

International Association for the Study of Pain. IASP Taxonomy. Pain terms. Neuropathic pain. Updated 2017 Dec 14. www.iasp-pain.org/Taxonomy#Neuropathicpain [cited 2018 May 1]

Burke D, Fullen BM, Stokes D, Lennon O. Neuropathic pain prevalence following spinal cord injury: A systematic review and meta-analysis. Eur J Pain. 2017 Jan;21(1):29-44. doi: 10.1002/ejp.905. Epub 2016 Jun 24. PMID: 27341614.

2) Mussigmann T, Bardel B, Lefaucheur JP. Resting-state electroencephalography

 (EEG) biomarkers of chronic neuropathic pain. A systematic review. 

Neuroimage. 2022;258:119351.

3) Jensen MP, Sherlin LH, Gertz KJ, Braden AL, Kupper AE, Gianas A, et al. 

Brain EEG activity correlates of chronic pain in persons

 with spinal cord injury: clinical implications. 

Spinal Cord. 2013;51(1):55-8

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