Driving plasticity in the motor cortex in recurrent low back pain

Abstract

The sensory and motor systems can reorganise following injury and learning of new motor skills. Recently we observed adaptive changes in motor cortical organisation in patients with recurrent low back pain (LBP), which are linked to altered motor coordination. Although changes in motor coordination can be trained and are associated with improved symptoms and function, it remains unclear whether these training-induced changes are related to reorganisation of the motor cortex. This was investigated using the model of a delay in postural activation of the deep abdominal muscle, transversus abdominis (TrA) in 20 individuals with recurrent LBP. Subjects were allocated to either motor skill training that involved isolated voluntary contractions of TrA, or a control intervention of self-paced walking exercise for 2 weeks. Electromyographic (EMG) activity was recorded from TrA bilaterally using intramuscular fine-wire electrodes. Motor cortical organisation using transcranial magnetic stimulation (TMS) and postural activation associated with single rapid arm movements were investigated before and after training. Motor skill training induced an anterior and medial shift in motor cortical representation of TrA, towards that observed in healthy individuals from our previous study. This shift was associated with earlier postural activation of TrA. Changes were not observed following unskilled walking exercise. This is the first observation that motor training can reverse reorganisation of neuronal networks of the motor cortex in people with recurrent pain. The observed relationship between cortical reorganisation and changes in motor coordination following motor training provides unique insight into potential mechanisms that underlie recovery.

The Effect of Cervical Spine Manipulation on Postural Sway in Patients With Nonspecific Neck Pain

“…Similar observations of pain-induced reorganisation of muscular representation within the motor cortex have been reported by other authors (Sanes & Donoghue, 2000;Tsao et al, 2010;. Interestingly, motor training to improve feed forward activation of trunk musculature is reported to induce changes in the motor cortical representation of the abdominal muscles closer toward those seen in asymptomatic individuals (Tsao et al, 2010). This suggests that the plastic changes in cortical representation may be involved in the development of altered motor performance seen in symptomatic individuals.…”

“…While this is well documented in patients with lower back (Hodges, 2001;Silfies, Mehta, Smith, & Karduna, 2009) and neck pain (Falla, Jull, & Hodges, 2004a), Tsao and colleagues noted that the degree of impairment in muscular engagement appeared to correlate with the reorganisation of trunk muscle schema in the motor cortex (Tsao et al, 2008). Similar observations of pain-induced reorganisation of muscular representation within the motor cortex have been reported by other authors (Sanes & Donoghue, 2000;Tsao et al, 2010;. Interestingly, motor training to improve feed forward activation of trunk musculature is reported to induce changes in the motor cortical representation of the abdominal muscles closer toward those seen in asymptomatic individuals (Tsao et al, 2010).…”

“…The generation and execution of motor commands that govern these muscles is the primary function of the motor cortex (Tsao, Galea, & Hodges, 2010). Recent research into the effect of pain on this area of the brain has revealed that patients, in comparison to asymptomatic individuals, demonstrate altered excitability of the motor cortex (Kirveskari, Vartiainen, Gockel, & Forss, 2010;Le Pera et al, 2001;Martin et al, 2008) and changes in the cortical representation of postural musculature (Tsao, Galea, & Hodges, 2008).…”

Proprioceptive use and sit-to-stand-to-sit after lumbar microdiscectomy: The effect of surgical approach and early physiotherapy

“…Hebert et al (2010) observed already decreased intramuscular fat in the multifidus after 8 weeks of physiotherapy following lumbar microdiscectomy. Several studies demonstrated that motor control exercises improve multifidus muscles function and postural control, both by changes on a peripheral (Hides et al, 1996;Tsao and Hodges, 2008) and central level (Tsao et al, 2010). By verifying the possibility to reverse the suboptimal proprioceptive use during postural control in lumbar surgery patients through physiotherapy, our results suggest that the lack of motor control contributes to the reduced functionality after surgery.…”

The Pearls and Pitfalls of Magnetic Resonance Imaging for the Spine

“…28,32,[55][56][57]65 Kader et al 62 have demonstrated a correlation between leg pain and MRI findings of increased atrophy and fatty infiltration of the ipsilateral lumbar multifidus, and others have demonstrated delayed and reduced recruitment of paraspinal muscles in response to functional tasks in patients with low back pain. 32,53,57,92 These findings have formed the foundation for clinical interventions that have shown to reduce painful symptoms. 26,53,75 Further evidence is also emerging to help reduce practice variability by assisting the clinician in determining which patient is likely to benefit from specific exercises.…”