Treatment of Chronic Low Back Pain Can Reverse Abnormal Brain Activity
It likely comes as no surprise that low back pain is the most common form of chronic pain among adults. Lesser known is the fact that those with chronic pain also experience cognitive impairments and reduced gray matter in parts of the brain associated with pain processing and the emotional components of pain, like depression and anxiety.
In a longitudinal study published in the Journal of Neuroscience, a group of pain researchers from McGill University and the McGill University Health Centre (MUHC) posed a fundamental question: If you can alleviate chronic low back pain, can you reverse these changes in the brain? The answer is yes, they say.
The team began by recruiting, through the Orthopedic Spine Clinic and the Alan Edwards Pain Management Unit at the MUHC, patients who have had low back pain for more than six months and who planned on undergoing treatment — either spinal injections or spinal surgery — to alleviate their pain. MRI scans were conducted on each subject before and six months after their procedures. The scans measured the cortical thickness of the brain and brain activity when the subjects where asked to perform a simple cognitive task. “When they came back in, we wanted to know whether their pain had lessened and whether their daily lives had improved,” said the study’s senior author, Laura S. Stone from McGill’s Alan Edwards Centre for Research on Pain. “We wanted to see if any of the pain-related abnormalities found initially in the brain had at least slowed down or been partially reversed.” Not only did the team observe recovery in the anatomical function of the brain, but also in its ability to function.
After the subjects were treated, researchers found increased cortical thickness in specific areas of the brain that were related to both pain reduction and physical disability. And the abnormal brain activity observed initially during an attention-demanding cognitive task was found to have normalized after treatment. While more research would be needed to confirm whether chronic pain actually causes these changes in the brain, Stone hypothesizes that chronic low back pain, at the very least, maintains these differences. “If you can make the pain go away with effective treatment,” she added, “you can reverse these abnormal changes in the brain.
”Reference: D. A. Seminowicz, T. H. Wideman, L. Naso, Z. Hatami-Khoroushahi, S. Fallatah, M. A. Ware, P. Jarzem, M. C. Bushnell, Y. Shir, J. A. Ouellet, L. S. Stone. Effective Treatment of Chronic Low Back Pain in Humans Reverses Abnormal Brain Anatomy and Function. Journal of Neuroscience, 2011; 31 (20): 7540
Physiological and clinical changes after therapeutic massage of the neck and shoulders.
Little is known regarding the physiological and clinical effects of therapeutic massage even though it is often prescribed for musculoskeletal complaints such as chronic neck pain. The study conducted by researchers from Neuromechanics Research Laboratory, at Auburn University, USA, investigated the influence of a standardized clinical neck/shoulder Therapeutic Massage intervention on physiological measures: assessing α-motoneurone pool excitability, muscle activity; and the clinical measure of range of motion (ROM) compared to a light touch and control intervention. Sixteen healthy adults participated in three, 20 min interventions: Control, Light Touch and Therapeutic Massage.
Analysis of the data indicated a decrease in FCR α-motoneurone pool excitability after Therapeutic Massage, compared to both the Light Touch or Control.EMG signal amplitude decreased after Therapeutic Massage by 13%, when compared to the control, and 12% as compared to Light Touch. The Therapeutic Massage intervention produced increases in cervical ROM in all directions assessed: flexion, lateral flexion, extension, and rotation.
Therapeutic Massage of the neck/shoulders reduced the α-motoneurone pool excitability of the flexor carpi radialis after Therapeutic Massage, but not after the Light Touch or Control. Moreover, decreases in the normalized EMG amplitude during MVIC of the upper trapezius muscle; and increases in cervical ROM in all directions assessed occurred after Therapeutic Massage, but not after the Light Touch or Control.
Blind people have a better sense of touch
A New research from McMaster University may answer a longstanding question: do blind people have a better sense of touch because the brain compensates for vision loss or because of heavy reliance on their fingertips? The study, published in the most recent edition of the Journal of Neuroscience, suggests daily dependence on touch is the answer.
Twenty-eight profoundly blind participants with varying degrees of Braille expertise and 55 normally sighted adults were tested for touch sensitivity on six fingers and both sides of the lower lip. Researchers reasoned that, if daily dependence on touch improves tactile sensitivity, then blind participants would outperform the sighted on all fingers, and blind Braille readers would show particular sensitivity on their reading fingers.
But if vision loss alone improves tactile sensitivity, then blind participants would outperform the sighted on all body areas, even those that blind and sighted people use equally often, such as the lips. "There have always been these two competing ideas about why blind people have a better sense of touch," explains Daniel Goldreich, corresponding author and a professor in the Department of Psychology, Neuroscience & Behaviour.
"We found that dependence on touch is a driving force here. Proficient Braille readers, those who might spend hours a day reading with their fingertips, performed remarkably better. But blind and sighted participants performed equally when the lips were tested for sensitivity."
Researchers used a specially designed machine which held the pad of the participant's fingertip perfectly still for the experiments. While the finger lay over a hole in the table, the machine pushed rods with textured surfaces through the opening until they met the fingertip. Researchers asked subjects to identify the patterns by touch. A similar test was performed on the lower lip.
Not only did blind participants do better than their sighted peers, but Braille readers, when tested on their readings hands, outperformed non-readers who were also blind. For Braille-reading participants, their reading fingers were more sensitive than their non-reading fingers.
Viscoelasticity of the muscle-tendon unit is returned more rapidly than range of motion after stretching.
Researchers from School of Health and Sport Sciences, Chukyo University, Japan studied the viscoelasticity of gastrocnemius medialis muscle and tendon after stretching. The study was published in Scandinavian Journal of Medicine Science Sports.
In 11 male participants, displacement of the myotendinous junction on the gastrocnemius medialis muscle was measured using ultrasonographic during the passive dorsiflexion test, in which the ankle was passively dorsiflexed at a speed of 1°per second to the end of the range of motion (ROM). Passive torque, representing resistance to stretch, was also measured using an isokinetic dynamometer. On five different days, passive dorsiflexion tests were performed before and 0, 15, 30, 60 or 90 min after stretching, which consisted of dorsiflexion to end ROM and holding that position for 1 min, five times.
As a result, end ROM was significantly increased at 0, 15 and 30 min after stretching as compared with each previous value. Passive torque at end ROM was also significantly increased after stretching. Although the stiffness of the muscle-tendon unit was significantly decreased immediately after stretching , this shift is recovered within 15 min.
These results showed that the retention time of the effect of stretching on viscoelasticity of the muscle-tendon unit was shorter than the retention time of the effect of stretching on end ROM.
Hand Pain? Cross Your Arms to Confuse the Brain.
New research suggests that if your hand hurts, simply crossing your arms will confuse the brain and reduce the pain intensity. However, don’t go smashing your thumb to put this to the test — there were limitations of this research to consider first.
Writing in the June 2011 edition of the journal Pain, an international team of researchers report using a laser to produce brief pin pricks of “pure pain” (pain without touch) on the hands of a small group of 8 volunteers. Pain stimuli were then repeated after subjects crossed their arms at the wrists. Subjects rated their pain during each condition and their brain responses to the pain were measured via electroencephalography (EEG).
Results from both the EEG and self-report measures revealed that the perception of pain was weaker when the arms were crossed. In a second experiment, electrically evoked non-painful sensations were applied. EEG and self-report measures were similar to the above findings — crossing the arms reduced perception of the sensations.
Researchers believe this happens because of conflicting information between two of the brain’s image maps: one for the body and a second for external space. For example, there is a cognitive map for the left external space corresponding to the left hand, and one for the right side/right hand. The maps work together, creating brain impulses in response to stimuli. When the arms are crossed, however, the two maps become mismatched and information processing becomes weaker — resulting in less perception of externally applied stimuli like touch or pain.
This might be a possible mechanism behind the analgesic effect of mirror therapy used to treat phantom pain in amputated limbs. In everyday application, the researchers suggest, “Perhaps, when we get hurt, we should not only ‘rub it better’ but also cross our arms.” However, before doing that, there are two important caveats to consider: 1) this was a laboratory experiment in a very small group of healthy volunteers, and 2) the authors concede that the magnitude of analgesic effects from this approach were too small to be clinically important.
So why was this research worthwhile? According to the researchers, it suggests that mechanisms by which sensory events emerge into awareness can also be used to modulate pain, and it could lead to novel clinical therapies to reduce pain that exploit the brain’s way of representing the body.
REFERENCE: Gallace A, Torta DME, Moseley GL, Jannetti GD. The analgesic effect of crossing the arms. Pain. 2011(Jun);152(6):1418-1423.Article from: http://updates.pain-topics.org/2011/05/hand-pain-cross-your-arms-to-confuse.html
Physiological Mechanism For Stress Reduction Resulting From Touch Massage
A study by Umea University, in Sweden, evaluated the physiological effects of touch massage and was published in the journal, Autonomic Neuroscience last year. Like other massage modalities, touch massage is provided to decrease stress, anxiety and pain. Often massage therapists observe decreases in blood pressure, heart rate, and respiration. These observations suggest massage modalities influence the autonomic nervous system and alter an individual's stress response. The autonomic nervous system is comprised of sympathetic and parasympathetic activity. It controls involuntary bodily functions, such as breathing and the heartbeat. Simply put these two synergistic components act as internal stress (sympathetic) and relaxation (parasympathetic) response systems, which work to maintain autonomic balance. The autonomic nervous system and stress response mechanisms have received considerable attention for explaining a physiological mechanism of massage. Lindgren and colleagues tackled the arduous task of evaluating the physiological effects of touch massage on stress responses in 22 healthy volunteers using a battery of bio-markers to identify autonomic nervous system responses.
Lindgren and colleagues used a crossover design method to conduct this study. In a crossover design, each participant is in both groups (treatment and control). At two separate occasions, each individual either receives the treatment of touch massage or rests in the supine position as a control. Using this method, participants can function as their own comparison with and without the treatment. Though crossover design has many advantages, like requiring smaller sample sizes, the disadvantage of crossover design methods is the carryover effect, where the treatment has lingering effects. If there were a strong carryover effect, we would expect to see the participants who receive treatment first having a different baseline when they return for the control session. However, there were no significant differences between massage first and rest first in the baseline measures taken immediately before the second session, so carryover effects should not influence these results.
Participants received touch massage on their hands and feet, which "consisted of stroking movements on the ventral and dorsal side of hands and feet along with circular movements on each finger and toe. Touch massage was performed for 80 min in the following order: 20 min each on the left hand, the right hand, the right foot, and the left foot." Participants in the control group rested in the same setting. Outcomes measures included heart rate and heart rate variability (the variation in time between heart beats), cortisol stress hormone levels from saliva, blood glucose, and serum insulin. Data were collected before, during, and after touch massage or rest session.
The main finding in this study for Lindgren and colleagues was, "After 5 minutes of touch massage there was a significant decrease in heart rate lasting for 65 min, indicating reduced stress response." Though findings suggested significant changes across several measures, "the only significant differences between the groups were the decreases in heart rate after 45 minutes and in the HF component [high frequency domain of heart rate variability] after 5 minutes." Group differences between treatment and control groups are typically the focus of studies such as this one, because these differences measure the effect resulting from the treatment. Though there were no significant differences between groups in levels of cortisol, glucose, and insulin, "Saliva cortisol and insulin levels decreased significantly after intervention, while the serum glucose level remained stable. A similar pattern, although less prominent was observed in the control group." The findings from this study suggest, "Touch massage reduces the heart rate by decreasing sympathetic nervous activity and evoking a compensatory decreased parasympathetic nervous activity in order to maintain autonomic balance." These findings suggest that after receiving touch massage the participants experienced a biological relaxation response - producing the experience of stress reduction.
As with all research, this study identified limitations to interpreting the findings of this study. First, "calm music" was played during the sessions, which could have had an effect; however, music was used in both groups, therefore touch massage served as the single outcome. Second, as with most massage studies the interpersonal interaction between the therapist and recipient could have affected the treatment. We cannot eliminate the effects of this interaction especially since there was no "sham massage" or "therapeutic touch" group included as a level in between treatment and control. One other potential limitation of the study is that the authors reported that five participants' heart rate and heart rate variability data were excluded due to arrhythmias. Given the already small sample size of less than two dozen individuals, decreasing the sample size by almost 25% for these data points could impact the ability to interpret and generalize these data findings. Further, it is possible that the trend observed of a greater decrease in cortisol following touch massage than following quiet rest and insulin level in this study could prove to be significant with larger sample sizes in future studies. Larger randomized clinical trials will provide evidence for generalizable findings to inform consumers about the effects and physiological mechanisms of touch massage.
This study provides evidence that supports one of the most popular theories for explaining the relaxing effects of massage therapy. Specifically, Lindgren and colleagues found that touch massage significantly reduces cortisol, although not significantly more so than quiet rest, and that massage significantly lowers heart rate. The findings of this study warrant future research to evaluate these physiological mechanisms in larger controlled clinical trials and with more diverse populations. But what does this mean for providers and touch massage recipients? Whether in a non-clinical or clinical setting touch massage can reduce stress for clients and patients. Though this is not likely new information to many providers, as observations of stress reduction are commonplace in the massage setting, Lindgren and colleagues have provided evidence to substantiate these observations, which support incorporating touch massage in individuals' wellness and healthcare plans to facilitate stress reduction and promote personal health.
Source: Lindgren L, Rundgren S, Winsö O, Lehtipalo S, Wiklund U, Karlsson M, Stenlund H, Jacobsson C, Brulin C. Physiological responses to touch massage in healthy volunteers. Autonomic Neuroscience: Basic and Clinical. 2010; 158: 105-110.Article from: http://www.massagetoday.com/mpacms/mt/article.php?id=14426
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