September 2, 2013
Connecting the dots
Recent reading on the diaphragm is helping me to connect the dots regarding the vestibular system and postural control. I thought I would share my thoughts and my reading list with you this month.
*The vestibular system is a powerhouse in the brain, influencing many things from the perception of movement to emotional regulation
*The vestibular system modulates the sensitivity of every other sensory system. New research even indicates that the vestibular system directly reduces the acute perception of pain!
*The vestibular system is intimately connected with the visual system by the Vestibulocular Reflex (VOR) which serves to keep the visual image in the middle of the visual field as the head is moving
*The vestibular system participates in the regulation of the activity of the respiratory diaphragm. This makes sense if we think about the fact that gravity and movement impact how the diaphragm needs to work.
*The diaphragm is a crucial inner core muscle, which participates in anticipatory postural control
*Vestibular system dysfunction has also been implicated in low muscle tone
So,
It makes total sense that our children with low tone have difficulty with vestibular input/processing. These children also frequently have difficulties using functional vision for postural control. They also have poor activation of their respiratory diaphragm, and consequently the pelvic floor muscles (because these muscles work as a team). This results in upper chest or belly breathing (=diaphragmatic) patterns and poor pelvic stability. All of these combined manifest in poor posture and inefficient postural control which compromises balance, gross motor and fine motor function. They also impact phonation, my SLP friends inform me.
Given this information, we should be addressing the vestibular system as an integral part of treatment for improved postural control.
Practical App:
For a child who is hypo-responsive in their vestibular processing, try priming the vestibular system prior to balance training.
Before working on balance activities, have your client participate in movement that will activate their vestibular system. Find out what they like to do – swing, spin, jump, twirl, run, even nodding their head creates vestibular input. Engage them in that activity for a defined length of time. Start with brief vestibular activation (to ensure that the system does not move into overload) and pair it with work on balance training. You can gradually increase the length of time for vestibular preparation activities or repeat them within a session if they are well tolerated. And as always, pay attention to alignment. A rib cage that is not stacked over a neutral pelvis changes the resting length of the diaphragm as well as head position and both of these impact negatively on vestibular system function. Remember, it’s all connected!
Further reading:
Bordoni B, Zanier E. Anatomic connections of the diaphragm: influence of respiration on the body system. 2013 J Multidiscip Healthc. 6: 281-91.
Ferrè EF. Balancing the somatosensation. 2013 http://www.bodyinmind.org/balancing-the-somatosensation/
Gandevia SC, Butler JE, Hodges PW, Taylor JL. Balancing acts: respiratory sensations, motor control and human posture. 2002 Clin Exp Pharmacol Physiol. 29:118-21.
Khan S, Chang R. Anatomy of the vestibular system: a review. 2013 Neurorehabil. 32:437-43.
Niedrignhaus M, Jackson PG, Evan STR, Verbalis JG, Gillis RA, Sahibzada N. Dorsal motor nucleus of the vagus: a site for evoking simultaneous changes in crural diaphragm activity, lower eosophageal sphincter pressure and fundus tone. 2008 Am J Physiol Integr Comp Physiol. 294: R121-31.
Yates BJ, Billig I, Cotter LA, Mori RL, Card JP. Role of the vestibular system in regulating respiratory muscle activity during movement. 2002 Clin Exp Pharmacol Physiol. 29: 112-7.
Young RL, Page AJ, Cooper NJ, Frisby CL, Blackshaw LA. Sensory and motor innervation of the crural diaphragm by the vagus nerves. 2010 Gastroenterol. 138: 1091-1101
Zur O, Ronen A, Melzer I, Carmeli E. Vestibulo-ocular response and balance control in children and young adults with mild-to-moderate intellectual and developmental disability: A pilot study. 2012 Res Dev Disabil. 34: 1951-7.