Gait is "all encompassing"

Last week we did a presentation on some very classic, yet challenging, gait video case presentations. This slide was a big piece of our presentation. 
We discussed that there are volitional and non-volitional movements that accompany the adequate and appropriate postural system control.
If you want to hurt your brain, read this paper. 
But in a nutshell what this paper says is that we have a constant switching between steady state cortical neuron discharge and and non-steady state discharge. For example, when we are on a flat road, no obstacles ahead of us, nothing but boring open road, the system sort of runs on an automated program, making limb movements calculated off of a normal unchallenged baseline. But, if there are roots, rocks, curbs, bikes to dodge, puddles to hurdle etc, the volitional and postural systems must change their operation, and alter limb movements based off of those postural systems as we pay attention, and negotiate the obstacles. There is this delicate symphony occurring between automated posture, calculated posture, rhythmic limb movements. In other words, there are volitional, reactionary and anticipatory plans and adjustments occurring in the background at all times.
But, make no mistake, bad, faulty, inefficient motor patterns can become automated if injuries are left, if they are left partially rehabed, if we teach our clients faulty patterns by overloading them and forcing adaptive patterns to inappropriate load or fatigue. These modifications occur deep in the CNS, much in the premotor cortices, and take into account body schema (their correct or distorted perception of where they are, or their limbs are, in space). Build strength or endurance on an altered schema, one that might be present from an old injury, and one will build strength and endurance where one does not want them to go. Properly training clients, offering corrective exercise and the like is far deeper that just asking your client to load and get stronger, unless you wish to assume that their limitations and compensations are unimportant. This takes us right back to the asymmetry debate, which we know so many love to dive into. Asymmetry is the norm of course, just don't be the person creating more of it for your client.

"Adaptive gait control requires constant recalibration of walking pattern to navigate different terrains and environments. For example, motor cortical neurons do not exhibit altered discharge during steady-state locomotion, but altered discharge occurs when the experimental animal has to overcome obstacles. Loops from the motor cortical areas to the basal ganglia and the cerebellum may contribute to this purpose (ie, contribute to accurate and adaptive movement control that requires volition, cognition, attention, and prediction). In contrast, cortical processing seems unnecessary during the automatic execution of locomotion. Rather, high-level processing may occur in the systems between the basal ganglia, cerebellum, and brainstem in the absence of conscious awareness. - TAKAKUSAKI , Neurophysiology of Gait: From the Spinal Cord to the Frontal Lobe. Movement Disorders, Vol. 28, No. 11, 2013

“I keep walking into doorframes,” : A visual aspect of problematic gait you likely have not considered.

Written by Dr. Shawn Allen

Recently i had an elderly client come in to see me, we were working on some arthritic knee problems post-total knee arthroplasty. He mentioned to me that he recently had eye surgery because he was having some gait difficulties. My brain immediately when into age related gait decline, you know, balance kind of stuff.  He mentioned that he was banging into door frames because he was not clearing the sides of the door frames and was also banging up his knees, ankles, thighs and toes on many other things.  He said he had been getting anxious about his gait and thought he might be experiencing some kind of neurologic gait problem. He wasn’t trusting his gait, he feared leaving his house. He happened to mention it to his eye doctor a few months ago and here is what he told him .  

“Your upper eye lids are drooping so much that they are obliterating your peripheral vision. You can’t avoid banging into things that you cannot see. Your peripheral vision is imperative for normal safe gait.”

Drooping eyelids are an inevitable effect of getting older, but the sagging eyelids can impair peripheral vision and magnify gait risks. The procedure known as a blepharoplasty is a simple procedure performed on the upper eyelid when the lid drops down and creates a lateral blind or fold blocking out the lateral eye fields. When looking to the extremes of lateral gaze or depending on peripheral vision this fold blocks the lateral field on the affected eye while the bridge of the nose blocks the same lateral field of the other eye. Effectively, the lateral gaze and peripheral vision becomes progressively narrowed. 

Watch the gait of your elderly clients. Observe how they move about your office, around furniture, tables, door frames. Ask if their gait is uncertain. Ask if they are running into things for no apparent reason.  Think about this next time you are walking in close proximity of the elderly, just because you see them in your peripheral vision, does not mean they can see you.  Remember, their balance and stability is likely not what yours is, it might not take much to knock them over for what appears to be little reason at all.

From the Graci study: 

“However, under CPO conditions (circumferential peripheral visual field occlusion), the doorframe led to a further reduction in crossing velocity and increase in trail-foot horizontal distance and lead-toe clearance, which may have been because of concerns about hitting the doorframe with the head and/or upper body.”

From their conclusions, “exteroceptive cues are provided by the central visual field and are used in a feed-forward manner to plan the gait adaptations required to safely negotiate an obstacle, whereas exproprioceptive information is provided by the peripheral visual field and used online to “fine tune” adaptive gait. The loss of the upper and lower peripheral visual fields together had a greater effect on adaptive gait compared with the loss of the lower visual field alone, likely because of the absence of lamellar flow visual cues used to control egomotion.”

Shawn Allen, one of the gait guys.

1. Optom Vis Sci. 2010 Jan;87(1):21-7. doi: 10.1097/OPX.0b013e3181c1d547.Utility of peripheral visual cues in planning and controlling adaptive gait.Graci V¹, Elliott DB, Buckley JG.

2. http://abcnews.go.com/blogs/health/2013/05/31/eye-lifts-fine-line-between-cosmetic-and-therapeutic/