Gait and the lower visual field.

Gait and the eyes. We forget about the eyes. If you have vision issues, your gait may change.
Gaze during adaptive gait involving obstacle crossing is typically directed two or more steps ahead where as visual information of the “in the moment” swinging lower-limb and its relative position during the task is available in the lower visual field. This study determined exactly when visual information is utilised to control/update lead-limb swing trajectory during obstacle negotiation.
In this study, when the lower visual field was blocked out the foot-placement distance and toe-clearance became significantly increased, suggesting the brain overcorrecting for safety. A logical assumption. “These findings suggest that lower visual field input is typically used in an online manner to control/update final foot-placement, and that without such control, uncertainty regarding foot placement causes toe-clearance to be increased.”

http://www.ncbi.nlm.nih.gov/pubmed/22424759

Irregular Arm Swing Could Be Early Sign Of Pending neurological disease.

Written by Dr. Shawn Allen

We’ve been saying this for quite some time now, the small subtle gait changes are often the first sign of things to come.

The attached article suggests that scientific measurement investigating irregular arm swing during gait could help diagnose the Parkinson’s disease earlier, giving greater opportunity to slow brain cell damage and disease progression.

In the study below Huang suggests that although we all know that classically the Parkinsonian disease is met with tremors, slow movements, stooped posture, rigid muscles, bradykinesia, speech changes etc, “by the time we diagnose the disease, about 50 to 80 percent of the critical cells called dopamine neurons are already dead,”

Previously, here at The Gait Guys, we have gone deep into discussions of arm swing and the phasic and anti-phasic natures of limb action in gait and how the four limbs interact neurologically, both centrally and peripherally. You can click here for just a sampling of our “arm swing” writings,   

In the study, because arm swing changes are one of the first gait parameters to diminish and decline, and because the decline is typically asymmetrical due to the fact that the disease is an asymmetrical one, the authors compared arm swing magnitude and asymmetry in patients with and without Parkinson’s as parameters to begin the assessments.  Most research to date has commented on the early loss of arm pendular swing but as they said here, “ but nobody had looked using a scientifically measured approach to see if the loss was asymmetrical or when this asymmetry first showed up,“ explained Huang.

What they discovered was that compared to the control group, “the Parkinson’s group showed significantly greater asymmetry in their arm swing (one arm swung significantly less than the other while walking),” and when the subjects walked faster, the arm swing increased but the amount of asymmetry remained unchanged.

On a slightly different tangent of thinking, an aside from the Parkinson’s disease disucussion, how truly sensitive is this limb swing thing you might ask ? Here, read this from this piece (How injury and pain reorganize the brain) we wrote a few years ago.

“Getting a cast or splint causes the brain to rapidly shift its resources to make righties function better as lefties, researchers found.
Right-handed individuals whose dominant arm had to be immobilized after an injury showed a drop in (brain) cortical thickness in the area that controls primary motor and sensory areas for the hand, Nicolas Langer, MSc, of the University of Zurich in Switzerland, and colleagues reported.
Over the same two-week period, white and gray matter increased in the areas that controlled the uninjured left hand, suggesting “skill transfer from the right to the left hand,” the group reported in the Jan. 17 issue of Neurology.
The findings highlight the plasticity of the brain in rapidly adapting to changing demands, but also hold implications for clinical practice, they noted.”

This article highlights the rapid changes in motor programs that occur. It does not take long for the body to begin to develop not only functional adaptations but neurologic changes at the brain level within days and certainly less than 2 weeks.

If you know your literature on this topic of arm swing symmetry, you know it is an arguable point.  According to the Lathrop-Lambach study (see link in the article just mentioned above), they mentioned that they feel a 10% baseline asymmetry is the norm.  This symmetry issue is an arguable point that no one is likely to ever win.  We tend to feel, as many others do, that asymmetry can be a major component and predictor to injury, and in today’s topic of discussion a possible determinant of higher level gait disease. 

Still think you should retrain arm swing ? Dive into our blog archives here on arm swing, you will find out that perhaps it is not your best first choice. Discover from our old writings who tends to dictate how much arm swing occurs. 

Shawn Allen, one of the gait guys

References:

http://www.medicalnewstoday.com/articles/173680.php

“Arm swing magnitude and asymmetry during gait in the early stages of Parkinson’s disease.”
Michael D Lewek, Roxanne Poole, Julia Johnson, Omar Halawa, Xuemei Huang
Gait & Posture, 2009, In Press, Corrected Proof, Available online 27 November 2009  DOI:10.1016/j.gaitpost.2009.10.013

Proof that the contralateral limbs are programmed. Wait, are you guys showing dog gait video today ? yup, and for good reason.

This is how good our eyes are trained at gait stuff.  How good are yours ? Can you pick out what we saw immediately when watching this clip ? It is something really cool, perhaps proof that contralateral limbs, upper and lower,  are programmed and automatic. Even in dogs apparently. Did you see it ?  You may have to have to watch the video several times.

The dog initially is striking with the left forelimb while pairing that with right hindlimb just after (remember, this is running gait, not walking) . Kind of like how in human gait the left arm swing is in sync with the right leg swing (both in either flexion or extension, at the same time). We believe the central pattern generator for gait occurs in an area of the spinal cord at the junction of the the thoracic and lumbar spines (just like in the large sauropod dinosaurs!) click here for more info

But what is really cool is that there is a sudden change at 0:23sec.  The dog changes midstride to strike first with the right forelimb and immediately alters the hind limb to strike first with the left. Can you see it ? Look again. Isn’t the nervous system amazing!

Just as in humans the pattern change seems to be immediate and subconscious.  The rhythm and sync is predictable. It appears that even in animals the arm swing topics of weeks ago on in-phase and anti-phase of the shoulder and pelvic girdles hold true.

Did you see it immediately ? It may take you time to train your eyes like ours, but if you watch enough videos perhaps you too will have gait observation superpowers. 

Limb swing, even in animals, offer information to learn from and extrapolate to humans. Bipeds, quadrupeds….we don’t discriminate.

Shawn and Ivo……..gait experts……. on many levels.