#uner tan

A theory for bipedal gait ? Ipsilateral interference between the foot and hand in quadrupedal gait.

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Human quadrupedalism is not an epiphenomenon caused by neurodevelopmental malformation and ataxia: Uner Tan Syndrome, Part 3

* Alert: Before you read this blog post you will do yourself a great degree of mental service by reading our 2 prior blog posts on this video.  There is an important learning progression here. Here are the links:

http://thegaitguys.tumblr.com/post/28332726553/the-hand-walkers-the-family-that-walks-on-all

http://thegaitguys.tumblr.com/post/78470419988/the-hand-walkers-part-2-uner-tan-syndrome-the

Note that in this video there is ipsilateral interference between the foot and hand in this quadrupedal gait. In this diagonal quadrupedal locomotion (QL) the forward moving lower limb is impaired from further forward progression by the posting up (contact) hand of the same side. This would not occur if the QL gait was non-diagonal (ie. unilateral), the forward progression of the lower limb would be met with same time forward progression of the upper limb, allowing a larger striding out of both limbs.  This would enable faster locomotion without increasing cadence (which would be the only way of speeding up in the diagonal QL), at the possible limitation of necessitating greater unilateral truncal postural control (which is a typical problem in some of these Uner Tan Syndrome individuals who typically have profound truncal ataxia).  

As the video progresses one can see that bipedal locomotion IS IN FACT POSSIBLE in Uner Tan syndrome individuals. 

This is the excerpt from the embedded video:

"Two adult siblings from a consanguineous famiy in Kars, Turkey, exhibited Uner Tan syndrome with severe mental retardation, and no speech, but with some developmental differences..  There was no homozygocity in the genetic analysis, but the extremely low socio-economic status suggested epigenetic changes occurred during pre- and post-natal development.  Quadrupedal locomotion in cases with Uner Tan syndrome exhibit interference between the ipsilateral extremities, and this also occurred in all tetrapods with diagonal sequence QL since this form of locomotion appeared around 400 MYA.  The ipsilateral limb interference might have been the triggering factor for bipedal locomotion in our ancestors, and walking upright would enhance their chances of survival, because of the benefits in the visual and manual domains. The ipsilateral interference theory is a novel theory for the evolution of bipedalism in human beings, and was first proposed by Uner Tan in 2014."

As Karaca, Tan & Tan (1) discussed in their article:

"In discussions of the origins of the habitual QL observed in Uner Tan syndrome, it was argued that this quadrupedalism might be an epiphenomenon caused by neurodevelopmental malformation and severe truncal ataxia (Herz et al., 2008). The present work will show that this argument may be untenable, presenting two individuals with QL who do not exhibit ataxia, and who have entirely normal brain images and cognitive functions."

As we mentioned in our last blog post,

"Tan and Ozcelik mentioned in their recent research, in UTS the obligate diagonal QL was associated with some genetic mutations and cerebellovermial hypoplasia, and was seen as an adaptive self-organizing response to limited balance. On the other  hand, the present work showed that human QL may spontaneously occur in humans with an unimpaired brain, probably using the ancestral locomotor networks for the diagonal sequence preserved for about the last 400 million years. (Shapiro and Raichien, 2005; Reilly et al., 2006)." (1)

Kind of brings some new "slap in the face" thoughts to the rehab "bird dog" exercise doesn't it !  Driving a 400 million year old quadruped motor pattern (ya, ya, we know it is a early-window primitive cross crawl infant neurodevelopmental pattern, we have been to Pavel Kolar seminars. Don't try to argue, just think past all this. Go get a beer or walk in the park and cogitate on this a bit, it is important.)

If you want to dive deeper into this kind of work,  you may want to go and look at some of our recent work on Arm Swing here. But don't forget to watch this video above again and pay close attention to what we mentioned here.

We received this video on Monday (March 3, 2014) directly from Dr. Uner Tan himself in Turkey. We are very grateful for all that he has been sharing with us behind the scenes and we are grateful for his research and for this budding relationship.  Thank you Dr. Tan !  

Dr. Shawn Allen, one of The Gait Guys

Reference: 

The Hand Walkers, Part 2. Uner Tan Syndrome, the new research.

A year ago we wrote our first piece on Uner Tan Syndrome. We have always been interested in the neurodevelopmental windows of children and their process of moving through the various movement phases in the hopes of gaining clean upright bipedal gait. In our clinics daily we see many soft signs of sensory-motor pattern aberrancies that result in foot problems such as lack of pronatory control, or torsional long bone abnormalities and failures to protect frontal plane deviations (to name a very small few). In fact, these soft seonsory-motor signs and patterns can be found globally if one knows what to look for.  In our clinics we rarely see the serious neuro-developmental problems but Uner Tan Syndrome (UTS) has always been one of interest to us. We recently received a very kind email from Turkey, from Dr. Uner Tan himself, asking to reference some of our work so this was a serious honor.  The email sparked us to look into his research to look for newer work and we were happy to find it. Before we start into the new research findings, you will want to take a few minutes to read our last blog piece on Uner Tan Syndrome: The Hand Walkers.

http://thegaitguys.tumblr.com/post/28332726553/the-hand-walkers-the-family-that-walks-on-all

This previous blog post discussed much of the research that was current at the time.  The following was from our previous blog post  on UTS  

UTS is a syndrome proposed by the Turkish evolutionary biologist Uner Tan. Persons affected by this syndrome walk with a quadrupedal locomotion and are afflicted with primitive speech, habitual quadrupedalism, impaired intelligence. Tan postulated that this is a plausible example of “backward evolution”. MRI brain scans showed changes in cerebellar development which you should know after a year of our blog reading means that balance and motor programming might be thus impaired.  PET scans showed a decreased glucose metabolic activity in the cerebellum, vermis and, to a lesser extent the cerebral cortex in the majority of the patients. All of the families assessed had consanguineous marriages in their lineage suggesting autosomal recessive transmission. The syndrome was genetically heterogeneous.  

However, some startling new research has recently surfaced and if most are paying attention, they will see the value in our 1000+ blog posts here at The Gait Guys but more so discover Dr. Tan’s most startling conclusion from the Frontiers in Neurology article below. We are currently moving through the most recent research so you will want to check in with us again soon for our follow up blog posts on this topic. 

Here was Dr. Tan’s et al abstract conclusion of his most recent research, and we think it is earth shattering.

Human quadrupedalism is not an epiphenomenon caused by neurodevelopmental malformation and ataxia.  

Two cases with quadrupedal locomotion (QL) were presented. In both cases, cognitive and psychiatric functions were normal and, no neurological deficits were observed, except for a sequel paralysis of left leg in Case 2. It was suggested that human QL (1) should not be considered as an epiphenomenon caused by neurodevelopmental malformation and ataxia, but (2) may be considered as a re-emergence of the ancestral diagonal QL, and (3) it may spontaneously emerge in humans with entirely normal brains, by taking advantage of neural networks such as central pattern generators that have been preserved for about 400 million years.

We will have more to come shortly, but for now, realizing that the human brain, even when normal, can take advantage of neural networks encompassing Central Pattern Generators (CPG’s) that have been suppressed for 400 million years is startling information in our opinion.

Check back in with us soon.

Dr. Shawn Allen, one of the gait guys

References: