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Adjusting Our Understanding
April 4, 2015 by Dr Matthew D. Long
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April 4, 2015 by Dr Matthew D. Long
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Adjusting Our Understanding
April 4, 2015 by Dr Matthew D. Long
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Adjusting the human frame is clearly the defining feature of the chiropractic profession. But there are still questions about what spinal manipulation is trying to achieve. What actually changes when a patient’s spine is adjusted and how does this improve their quality of life? To answer this we need to appreciate how contemporary models try to explain the nature of spinal disorders...
Over recent years our understanding of spinal stability has evolved considerably. Notions of static misalignment, or simple muscle weakness, have gradually changed to incorporate newer evidence about the role of dynamic control mechanisms, and how these might go awry. We have looked at these concepts previously in this Blog (here, here, here, here, here and here) and noted that many of our patients are likely suffering from deficits in sensorimotor control. In other words, injury occurs when a patient fails to detect inappropriate motion and rein it in with a precisely matched muscular response.
The human spine is a hugely complex structure that is simultaneously juggling two competing interests - to remain flexible and to remain stable. The only way that these two opposing demands can be reconciled is to provide sensitive feedback mechanisms that can monitor the shifting loads and stresses upon spinal tissues and report back to the brain in a timely fashion. But the literature now suggests that our patients can and do suffer from problems of spinal positional awareness (1,2). Furthermore, the implications of any such deficiency are quite profound.
Proprioceptive data from the spine is used for many tasks, not simply tracking the motion of individual spinal bones. Firstly, it is combined with vestibular and visual information to assist with balance and orientation. Not surprisingly, those with a history of spinal pain show increased postural sway and greater trunk repositioning errors (3,4). In addition, this tendency appears to diminish once pain has abated (5,6). But it goes deeper than pain.
Postural data is used extensively by the brain to adapt humans to their environment. Our visual system, in particular, is exquisitely sensitive to any disturbance in vestibular performance - particularly when signals from the cervical spine are disrupted (7,8). For this reason visual symptoms are common in those suffering from spinal injury. Even more interesting, children with dyslexia also show greater postural sway (9).
Perhaps less obvious is the psychological fallout of subtle balance disorders. Anxiety has been shown to increase in those with greater postural sway (10,11), which makes sense if we consider the survival implications of decreased stability. As confidence in our ability to move decreases we necessarily have to increase our vigilance, prompting heightened anxiety. This effect has been shown in children (12) and in adults, and tends to worsen with age (13,14). What's more, the effect is even more insidious when we realise that our underlying balance strategy changes as we get older. With advancing age our vestibular system declines and we tend to rely more upon proprioceptive signalling from the neck (15). So it seems important that chiropractors seek to improve spinal proprioception in older patients to improve balance and reduce the risk of falling. Not only that, but age is also commonly accompanied by deteriorating performance in autonomic control parameters, such as blood pressure. We should therefore appreciate that the vestibular system uses postural information from the neck to influence the autonomic nervous system, particularly those areas responsible for cardiovascular and respiratory control (16,17). Interestingly, research has shown that balance related walking exercises (such as on a cobblestone mat) improved blood pressure in the elderly more than simple walking alone (18).
With all of this in mind it is worth pausing to reflect upon what it is that chiropractors are trying to achieve when manipulating the spine. Is it really a repositioning of errant bony structures? Or are we actually using manipulation as a novel sensory tool to improve proprioceptive feedback from the spine to the brain? This is certainly an idea that is now gaining greater support from the research community, with a recent paper in The Spine Journal adding further insight (19)...
If we are indeed altering the flow of sensory information from the spine to the brain, then this should be reflected in measurable changes to spinal control. The challenge that we have faced thus far is how to measure this. Until now the emphasis has been upon examining global range of motion or muscle strength to see whether this changes after manipulation. However, there is little consensus in the literature about whether there is any significant alteration to such general parameters of spinal function. But what about other aspects of spinal performance?
In the paper by Mieritz et al they looked beneath the superficial measurement of ROM and focussed upon important features of control. Importantly, they compared the effects of a 12-week course of spinal manipulation with both supervised and home-based exercises. According to the authors,
Over recent years our understanding of spinal stability has evolved considerably. Notions of static misalignment, or simple muscle weakness, have gradually changed to incorporate newer evidence about the role of dynamic control mechanisms, and how these might go awry. We have looked at these concepts previously in this Blog (here, here, here, here, here and here) and noted that many of our patients are likely suffering from deficits in sensorimotor control. In other words, injury occurs when a patient fails to detect inappropriate motion and rein it in with a precisely matched muscular response.
The human spine is a hugely complex structure that is simultaneously juggling two competing interests - to remain flexible and to remain stable. The only way that these two opposing demands can be reconciled is to provide sensitive feedback mechanisms that can monitor the shifting loads and stresses upon spinal tissues and report back to the brain in a timely fashion. But the literature now suggests that our patients can and do suffer from problems of spinal positional awareness (1,2). Furthermore, the implications of any such deficiency are quite profound.
Proprioceptive data from the spine is used for many tasks, not simply tracking the motion of individual spinal bones. Firstly, it is combined with vestibular and visual information to assist with balance and orientation. Not surprisingly, those with a history of spinal pain show increased postural sway and greater trunk repositioning errors (3,4). In addition, this tendency appears to diminish once pain has abated (5,6). But it goes deeper than pain.
Postural data is used extensively by the brain to adapt humans to their environment. Our visual system, in particular, is exquisitely sensitive to any disturbance in vestibular performance - particularly when signals from the cervical spine are disrupted (7,8). For this reason visual symptoms are common in those suffering from spinal injury. Even more interesting, children with dyslexia also show greater postural sway (9).
Perhaps less obvious is the psychological fallout of subtle balance disorders. Anxiety has been shown to increase in those with greater postural sway (10,11), which makes sense if we consider the survival implications of decreased stability. As confidence in our ability to move decreases we necessarily have to increase our vigilance, prompting heightened anxiety. This effect has been shown in children (12) and in adults, and tends to worsen with age (13,14). What's more, the effect is even more insidious when we realise that our underlying balance strategy changes as we get older. With advancing age our vestibular system declines and we tend to rely more upon proprioceptive signalling from the neck (15). So it seems important that chiropractors seek to improve spinal proprioception in older patients to improve balance and reduce the risk of falling. Not only that, but age is also commonly accompanied by deteriorating performance in autonomic control parameters, such as blood pressure. We should therefore appreciate that the vestibular system uses postural information from the neck to influence the autonomic nervous system, particularly those areas responsible for cardiovascular and respiratory control (16,17). Interestingly, research has shown that balance related walking exercises (such as on a cobblestone mat) improved blood pressure in the elderly more than simple walking alone (18).
With all of this in mind it is worth pausing to reflect upon what it is that chiropractors are trying to achieve when manipulating the spine. Is it really a repositioning of errant bony structures? Or are we actually using manipulation as a novel sensory tool to improve proprioceptive feedback from the spine to the brain? This is certainly an idea that is now gaining greater support from the research community, with a recent paper in The Spine Journal adding further insight (19)...
If we are indeed altering the flow of sensory information from the spine to the brain, then this should be reflected in measurable changes to spinal control. The challenge that we have faced thus far is how to measure this. Until now the emphasis has been upon examining global range of motion or muscle strength to see whether this changes after manipulation. However, there is little consensus in the literature about whether there is any significant alteration to such general parameters of spinal function. But what about other aspects of spinal performance?
In the paper by Mieritz et al they looked beneath the superficial measurement of ROM and focussed upon important features of control. Importantly, they compared the effects of a 12-week course of spinal manipulation with both supervised and home-based exercises. According to the authors,
"Specifically, we wanted to analyze the change in spinal ROM, maximum flexion velocity, phase-plot area, jerk index (smoothness of motion), and two circumduction area motion parameters in 199 chronic LBP patients over a 12-week intervention period and analyze the effect of 12 weeks of spinal manipulation therapy, supervised trunk exercise, or home exercise on spinal lumbar motion ability."
These features were chosen "to obtain a more complete representation of spinal motion biomechanics than achieved by sagittal plane ROM alone." So what did they find?
"For the cohort as a whole, lumbar region motion parameters were altered over the 12- week period, except for the jerk index parameter. The group receiving spinal manipulation changed significantly in all, and the exercise groups in half, the motion parameters included in the analysis. The spinal manipulation group changed to a smoother motion pattern (reduced jerk index), whereas the exercise groups did not."
So it seems that all interventions were beneficial, but only spinal manipulation resulted in measurably smoother movement - and quite significantly so. This is important, as smooth motion is a pre-requisite for fine control. Many of our patients suffer acute episodes of pain during innocuous daily movements, and it is suggested that failure to adequately control smooth movement lies at the core of the problem. So it just might be that spinal manipulation has an important role in restoring joint sensitivity and movement control, and thus help our patients in a number of profound ways.
Something to think about...
Dr Matthew D. Long
BSc (Syd) M.Chiro (Macq)
Dr Matthew D. Long
BSc (Syd) M.Chiro (Macq)
References:
1. O'Sullivan, P. B., Burnett, A., Floyd, A. N., Gadsdon, K., Logiudice, J., Miller, D., & Quirke, H. (2003). Lumbar repositioning deficit in a specific low back pain population. Spine, 28(10), 1074–1079. doi:10.1097/01.BRS.0000061990.56113.6F
2. Rausch Osthoff, A.-K., Ernst, M., Rast, F., Mauz, D., Graf, E., Kool, J., & Bauer, C. (2014). Measuring lumbar reposition accuracy in patients with unspecific low back pain – Systematic Review and Meta-analysis. Spine, 1. doi:10.1097/BRS.0000000000000677
3. Popa, T., Bonifazi, M., Volpe, della, R., Rossi, A., & Mazzocchio, R. (2007). Adaptive changes in postural strategy selection in chronic low back pain. Experimental Brain Research Experimentelle Hirnforschung Expérimentation Cérébrale, 177(3), 411–418. doi:10.1007/s00221-006-0683-4
4. van Daele, U., Hagman, F., Truijen, S., Vorlat, P., van Gheluwe, B., & Vaes, P. (2009). Differences in balance strategies between nonspecific chronic low back pain patients and healthy control subjects during unstable sitting. Spine, 34(11), 1233–1238. doi:10.1097/BRS.0b013e31819ca3ee
5. Ruhe, A., Fejer, R., & Walker, B. (2011). Is there a relationship between pain intensity and postural sway in patients with non-specific low back pain? BMC Musculoskelet Disord, 12(1), 162. doi:10.1186/1471-2474-12-162
6. Ruhe, A., Fejer, R., & Walker, B. (2012). Pain relief is associated with decreasing postural sway in patients with non-specific low back pain. BMC Musculoskelet Disord, 13(1), 39. doi:10.1186/1471-2474-13-39
7. Treleaven, J., & Takasaki, H. (2014). Characteristics of visual disturbances reported by subjects with neck pain. Manual Therapy, 19(3), 1–5. doi:10.1016/j.math.2014.01.005
8. Treleaven, J. (2008). Sensorimotor disturbances in neck disorders affecting postural stability, head and eye movement control. Manual Therapy, 13(1), 2–11. doi:10.1016/j.math.2007.06.003
9. Stoodley, C. J., Fawcett, A. J., Nicolson, R. I., & Stein, J. F. (2005). Impaired balancing ability in dyslexic children. Experimental Brain Research Experimentelle Hirnforschung Expérimentation Cérébrale, 167(3), 370–380. doi:10.1007/s00221-005-0042-x
10. Balaban, C. D. (2002). Neural substrates linking balance control and anxiety. Physiology & Behavior, 77(4-5), 469–475.
11. Balaban, C. D., & Thayer, J. F. (2001). Neurological bases for balance-anxiety links. Journal of Anxiety Disorders, 15(1-2), 53–79.
12. Stins, J. F., Ledebt, A., Emck, C., van Dokkum, E. H., & Beek, P. J. (2009). Patterns of postural sway in high anxious children. Behavioral and Brain Functions : BBF, 5, 42. doi:10.1186/1744-9081-5-42
13. Boucher, P., Descarreaux, M., & Normand, M. C. (2008). Postural control in people with osteoarthritis of the cervical spine. Journal of Manipulative and Physiological Therapeutics, 31(3), 184–190. doi:10.1016/j.jmpt.2008.02.008
14. Uthaikhup, S., Jull, G., Sungkarat, S., & Treleaven, J. (2012). The influence of neck pain on sensorimotor function in the elderly. Archives of Gerontology and Geriatrics, 55(3), 667–672. doi:10.1016/j.archger.2012.01.013
15. Schweigart, G., Chien, R.-D., & Mergner, T. (2002). Neck proprioception compensates for age-related deterioration of vestibular self-motion perception. Experimental Brain Research Experimentelle Hirnforschung Expérimentation Cérébrale, 147(1), 89–97. doi:10.1007/s00221-002-1218-2
16. Jian, B. J., Acernese, A. W., Lorenzo, J., Card, J. P., & Yates, B. J. (2005). Afferent pathways to the region of the vestibular nuclei that participates in cardiovascular and respiratory control. Brain Research, 1044(2), 241–250. doi:10.1016/j.brainres.2005.03.010
17. Bolton, P. S., & Ray, C. A. (2000). Neck afferent involvement in cardiovascular control during movement. Brain Research Bulletin, 53(1), 45–49.
18. Li, F., Fisher, K. J., & Harmer, P. (2005). Improving physical function and blood pressure in older adults through cobblestone mat walking: a randomized trial. Journal of the American Geriatrics Society, 53(8), 1305–1312. doi:10.1111/j.1532-5415.2005.53407.x
19. Mieritz, R. M., Hartvigsen, J., Boyle, E., Jakobsen, M. D., Aagaard, P., & Bronfort, G. (2014). Lumbar motion changes in chronic low back pain patients: a secondary analysis of data from a randomized clinical trial. The Spine Journal, 14(11), 2618–2627. doi:10.1016/j.spinee.2014.02.038
1. O'Sullivan, P. B., Burnett, A., Floyd, A. N., Gadsdon, K., Logiudice, J., Miller, D., & Quirke, H. (2003). Lumbar repositioning deficit in a specific low back pain population. Spine, 28(10), 1074–1079. doi:10.1097/01.BRS.0000061990.56113.6F
2. Rausch Osthoff, A.-K., Ernst, M., Rast, F., Mauz, D., Graf, E., Kool, J., & Bauer, C. (2014). Measuring lumbar reposition accuracy in patients with unspecific low back pain – Systematic Review and Meta-analysis. Spine, 1. doi:10.1097/BRS.0000000000000677
3. Popa, T., Bonifazi, M., Volpe, della, R., Rossi, A., & Mazzocchio, R. (2007). Adaptive changes in postural strategy selection in chronic low back pain. Experimental Brain Research Experimentelle Hirnforschung Expérimentation Cérébrale, 177(3), 411–418. doi:10.1007/s00221-006-0683-4
4. van Daele, U., Hagman, F., Truijen, S., Vorlat, P., van Gheluwe, B., & Vaes, P. (2009). Differences in balance strategies between nonspecific chronic low back pain patients and healthy control subjects during unstable sitting. Spine, 34(11), 1233–1238. doi:10.1097/BRS.0b013e31819ca3ee
5. Ruhe, A., Fejer, R., & Walker, B. (2011). Is there a relationship between pain intensity and postural sway in patients with non-specific low back pain? BMC Musculoskelet Disord, 12(1), 162. doi:10.1186/1471-2474-12-162
6. Ruhe, A., Fejer, R., & Walker, B. (2012). Pain relief is associated with decreasing postural sway in patients with non-specific low back pain. BMC Musculoskelet Disord, 13(1), 39. doi:10.1186/1471-2474-13-39
7. Treleaven, J., & Takasaki, H. (2014). Characteristics of visual disturbances reported by subjects with neck pain. Manual Therapy, 19(3), 1–5. doi:10.1016/j.math.2014.01.005
8. Treleaven, J. (2008). Sensorimotor disturbances in neck disorders affecting postural stability, head and eye movement control. Manual Therapy, 13(1), 2–11. doi:10.1016/j.math.2007.06.003
9. Stoodley, C. J., Fawcett, A. J., Nicolson, R. I., & Stein, J. F. (2005). Impaired balancing ability in dyslexic children. Experimental Brain Research Experimentelle Hirnforschung Expérimentation Cérébrale, 167(3), 370–380. doi:10.1007/s00221-005-0042-x
10. Balaban, C. D. (2002). Neural substrates linking balance control and anxiety. Physiology & Behavior, 77(4-5), 469–475.
11. Balaban, C. D., & Thayer, J. F. (2001). Neurological bases for balance-anxiety links. Journal of Anxiety Disorders, 15(1-2), 53–79.
12. Stins, J. F., Ledebt, A., Emck, C., van Dokkum, E. H., & Beek, P. J. (2009). Patterns of postural sway in high anxious children. Behavioral and Brain Functions : BBF, 5, 42. doi:10.1186/1744-9081-5-42
13. Boucher, P., Descarreaux, M., & Normand, M. C. (2008). Postural control in people with osteoarthritis of the cervical spine. Journal of Manipulative and Physiological Therapeutics, 31(3), 184–190. doi:10.1016/j.jmpt.2008.02.008
14. Uthaikhup, S., Jull, G., Sungkarat, S., & Treleaven, J. (2012). The influence of neck pain on sensorimotor function in the elderly. Archives of Gerontology and Geriatrics, 55(3), 667–672. doi:10.1016/j.archger.2012.01.013
15. Schweigart, G., Chien, R.-D., & Mergner, T. (2002). Neck proprioception compensates for age-related deterioration of vestibular self-motion perception. Experimental Brain Research Experimentelle Hirnforschung Expérimentation Cérébrale, 147(1), 89–97. doi:10.1007/s00221-002-1218-2
16. Jian, B. J., Acernese, A. W., Lorenzo, J., Card, J. P., & Yates, B. J. (2005). Afferent pathways to the region of the vestibular nuclei that participates in cardiovascular and respiratory control. Brain Research, 1044(2), 241–250. doi:10.1016/j.brainres.2005.03.010
17. Bolton, P. S., & Ray, C. A. (2000). Neck afferent involvement in cardiovascular control during movement. Brain Research Bulletin, 53(1), 45–49.
18. Li, F., Fisher, K. J., & Harmer, P. (2005). Improving physical function and blood pressure in older adults through cobblestone mat walking: a randomized trial. Journal of the American Geriatrics Society, 53(8), 1305–1312. doi:10.1111/j.1532-5415.2005.53407.x
19. Mieritz, R. M., Hartvigsen, J., Boyle, E., Jakobsen, M. D., Aagaard, P., & Bronfort, G. (2014). Lumbar motion changes in chronic low back pain patients: a secondary analysis of data from a randomized clinical trial. The Spine Journal, 14(11), 2618–2627. doi:10.1016/j.spinee.2014.02.038