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giovedì 7 gennaio 2016


Ooooh hallo dear English speaking-thinking-reading visitor, welcome back to me @sciencemug, the blog that talks about science, the subterranean war penguins fight to overcome bunnies and become the new official Easter pets, and the pressing issue of carob addiction among the Santa’s reindeers.
Aaaand that does all of this in Eng?ish, a language that is to real English what Alien vs Predator was to a “non-commercial art driven only project”, “the soup of the day” to something one orders lightheartedly at the restaurant after having seen Fight club, aaaand homeopathy to something that actually work.

Sooo, there’re Dr. Donath and these five other scientists of the University of Basel who do an experiment to test the probability Santa Claus has to trip and fall and injury himself while doing his job on Xmas Eve.

The researchers recruit seventeen 20-40 years old, fit, healthy males for their experiment. A bunch of these guys is dressed up with Santa’s garb and handed up with a 20 kilograms [pick the joke about the metric-system AKA SI that you prefer and say it outloud three times in a row in front of a splintered mirror, then spit on your left hand and make a 180 degree turn on yourself… And realize that there’s no sense at all in it (I mean, I’m not talking of the SI, that’s absolutely rational and functional, no, I was referring to the things I mentioned after the SI)… Gee, are you always so gullible or is it just that there’s a sensible lack of oxygen in your brain since your stomach is sucking most of the blood given you’re still digesting all the food you've gulped down during the holidays?] heavy sack. This is the Santa Group (SG).  The other guys are in the Non Santa Group (NSG) and, as you can imagine, they dress normally and carry no sack.

All the volunteers take three tests, two to check their gait (a walk along a short path and a brief session on a treadmill), and one to monitor their sway (a short stand on a plate connected with sensors). The volunteers take all tests barefoot (in order to exclude anything that can alter their responses during the tests. Or, maybe, but it’s just a guess, ‘cause Donath et al’s initial idea, before it were sunk by the lack of funds, was to couple their experiment with that of a group of Lapp endocrinologists interested in determining the amount of sweat - and therefore the intensity of the stink - produced by Santa’s feet on Xmas Eve and to set, like that, the level of biohazard he represents for the children of the world exposed to high doses of his “residuals” on Xmas early morning SM’s Note).

I sway (by sciencemug)
I S.W.A.Y. (by sciencemug)

Moreover, the Donath’s volunteers go for the tests both while focusing just on them, and while doing at the same time also a
mental exercise.
The mental things planned by Donath and colleagues are two. One is to memorize the name of two of Santa’s reindeers* and then spell backward every third letter of such names (and this is done during the “walkway” and the “sway” tests). The other one (done during the “treadmill” test) is to “count backwards (by three) from a three digit number[Donathet al 2015; (P)] (ah, these sadistic researchers!)

So, the tests.

The first one brings the volunteers on a 10 meters long walkway.

The guys stroll for three times along the pathat a self-chosen comfortable walking speed(P) while their gaits parameters are monitored by a photoelectric instrument. Basically the tool is made of two bars, the emitter and the receiver. The bars are positioned on the sides of the walkway and each of ‘em is loaded with dozens of LEDs. The LEDs of the emitter communicate on an infrared frequency with their bros on the receiver. When something (be it a reindeer running dry frantically looking for its carob pusher, an old fat man who likes red suits, is too lazy to shave and is delusional about the content of hissack”, or a bunch of guys whod do anything for a good mark or a couple of Swiss Francs) passes between the bars and so interrupts the LEDsinfrared chat, well, the system detects it and, thanks to a dedicated software, calculates the duration and position of the interference with an accuracy of 1/1000 of a second and a resolution of 1.401 centimeters. 

The second of the “gait tests” brings the volunteers on a sensor loaded treadmill rolling at their habitual walking speed. The guys walk 400 consecutive steps on the hyper technological gym tool while their “vertical ground reaction forces [GRF] ([namely the] acceptance and [the toe] push off phase)(P) are recorded.

The third test, the “sway test”, is more… Static. The guys stand for half a minute on a force plate –surprise surprise- connected with sensors that measure the “sway path of the center of pressure(P). The human guinea pigs do the sway test three times. They stand on the plate as still as possible, with one foot lined right behind the other, and while staring “a spot marked on the nearby wall (distance:1.5 m, height: 1.75 m [the average height of the participants is 1.79m SM’s Note])(P). Besides, during the test, the normally dressed guys (NSG) keep their hands on the hips, while the Santa-like ones (SG) carry the sack on their right shoulder.

Sooo, the Donath’s science bunch, once done with their measurements, find out that… Ah-ah! After the commercial… 

Do you suffer of “morning stiffness” and when you wake up and try to walk you feel like a Tin Man that slept, after spending 72 hours in a row binge drinking oil and tabasco sauce, outdoor in the moor of Northern England, under a heavy autumn rain and a bunch of angry pigeons?
Try “Eggnoglin”! Eggnoglin, a cream to put on your junctions three hundreds seventy eight times every forty nine minutes in order to finish the stick once 
Eggnoglin by @sciencemug
Eggnoglin by @sciencemug
every half a hour, be obsessed every fifteen minutes by the fear to receive a visit from “Fluffy”, the muscle of the loan shark you went to have the money you needed to buy this preparation, and forget, like that, the pain you feel at every and each step you take.
“Eggnoglin”, and your escape-jogging experience will never be the same!

Soo, Dr Donath and colleagues find out that both wearing the Santa’s apparel plus sack [“Santa-effects” (P) (Se)] and doing the mental exercise during the tests [“Dual-task effects” (P) (Dte)] negatively influence the volunteers’ gait and sway.

Although “[s]ignificant ‘‘Santa’’x ‘‘Dual-task’’ interaction effects [are] not observed(P), the Se only and the Dte only are indeed enough to provoke an increase in the sway, and also in the stride time, width and variability (P). The single effects are then responsible for a sensible reduction in the stride length and in the gait velocity and cadence (steps/minute) (P).

Moreover the researchers observe also variations in the GRF, the ground reaction forces: “decreased forces for dual tasking, increased forces for the Santa condition(P).
In other words, the effects cause a deterioration of the overall balance and walking performances of the guys pushing up, a lot, the probability of a fall.

Soo, Donath and colleagues conclude their peculiar paper paying an homage to “the engagement of our credulous participants [AKA the seventeen volunteers]” (P), but before this, they put down on the scientific Xmassy page, some, well, wise conclusions that are worthy to read as they’ve been stated:Santa Claus (even at a younger age) has a tremendously increased fall risk when carrying heavy Christmas presents totalling 20 kg. Cognitive loads [the mental exercises SM’s N] additionally impair his neuromuscular performance. An emotionally stressed Santa Claus transporting heavy presents is at a higher risk of falling. We shed light on the fact that Christmas may not be saved, unless SC completes physical [and cognitivel] training. We must properly educate today’s youth –the lab pals go on- about considering the idea of spreading the delivery period across several days in order to release pressure on jolly old SC […] Although parents will need to suffer from dealing with dissatisfied and whiney kids, the future generation of kids will be more humble and society will be healthier as a whole. This point needs further investigation.(P) Aah, these funny scientists…

Science vs Chores (1-0) (by sciencemug)
Science vs Chores (1-0) (by sciencemug)

Buuuut, but, I know that, at this point, although amused by the idea some real scientists did a real experiment to test a real hypothesis about an [SPOILER ALERT! SPOILER ALERT!] imaginary character, well, you, dear English speaking-thinking-reading visitor, you are wondering why, for the Holy Mother of all the Scandinavian reindeers, time, and especially money, have been put on such an apparently useless reseaerch project.

Weeell, well, dear skeptic you, scientist can be ironic and playful, but they always have a purpose.

Follow me.

About one third of the people aged 65 years or more and about a half of those aged 85 or morefall at least once a year and the probability of falling again increases after each fall(1). The consequence of this is a drastic deterioration of elders’ life’s quality. If not worst: “[f]alls are the leading cause of injury deaths and the most common cause of disability, premature nursing home admissions, medical costs, and hospitalizations among people 65 years and over.(2). 

So, dear reader, to find a way to somehow topple this fall risk could shrink it by a 30-40% (2) and save a lot pain and lives.

Humans capability to walk is negatively affected by age. Older folks, even if healthy, as a matter of fact have a slower and shorter stride and a bigger stride variability and sway if compared with young people (1) (does this remind you of something just read?).

Some of the above mentioned changes in the elders’ gait are indeed used to tackle their balance issues and stabilize them while on a stroll. Their brains, in short, try to compensate the deficits of the rest of their bodies.

However, older people suffer from withering of parts of the brain, worsening of synaptic connections and loss of brain mass. These things are probably connected with the deterioration of the vascular system and therefore of the blood flow that eventually lead to a drop in the proper irroration of the brain. The consequence of such age related physical brain damages is a decline of the cognitive functions, especially those very important for the ability to walk without tripping, meaning the ones used for activities like “obstacle avoidance, navigation along a planned route, watching for pedestrian and vehicular traffic [and so on]” (1). 

Ok, quick recap: grandpas and grandmamas find more difficult to walk in general but their brains can partially patch that. However the elders have battered brains, so the higher cognitive functions that they use to keep walking straight are progressively shrinking.  
So old fellas find very hard to walk while doing other things, especially when those things arecognitive tasks that involve internal interfering factors (3). One example of this kind of tasks ismental tracking”, an exercisethat requires holding information in the mind while performing a mental process(3) and thus can be used to test how good is a person at processing informations quickly and staying focused.

So, to sum up, elders, “due to declines of the neuromuscular postural control system(P) are already bad at walking per se, but they’re even badder at walking and, at the same time, processing information quickly and stay focused
The simple and plain conclusion of this perfect storm is this: old people have, as respect to young lads, less of those physical and cognitive abilities that help to avoid falling and breaking your hips/legs/skull.

Soooo, my dearest reader, to come to a full circle, the fact that even a young dude’s ability to walk be sensibly impaired by a Santa’s suite+sack and by a mental exercise (like it happened to Dr Donath and colleagues’ volunteers) is a further evidence that cognitive impairment and physical difficulties are veeery bad for balance. 
Hence, Donath’s lab bunch’s final advise about the allegedly over 65 Santa doing, as a routine, physical and mental training not to fall is indeed an advice meant for the very real elders of the very very (even too much at times…) real world.

Happy New Year pals!

Ok, ok, I was joking on the previous post. Here the names: Dasher, Dancer, Prancer, Vixen, Comet, Cupid, Donner, Blitzen and Rudolph. Cheers!

The paper this post is about (P)
- Donath, L., Roth, R., Lichtenstein, E., Elliot, C., Zahner, L., and Faude, O. (2015). Jeopardizing Christmas: Why spoiled kids and a tight schedule could make Santa Claus fall? Gait Posture 41, 745-749.

1- Beurskens, R., and Bock, O. (2015). Age-related deficits of dual-task walking: a review. Neural Plast 2012, 131608.
2- Jones, T. S., Ghosh, T. S., Horn, K., Smith, J., and Vogt, R. L. (2011). Primary care physicians perceptions and practices regarding fall prevention in adult's 65 years and over. Accid Anal Prev 43, 1605-1609.
Al-Yahya, E., Dawes, H., Smith, L., Dennis, A., Howells, K., and Cockburn, J. (2010). Cognitive motor interference while walking: a systematic review and meta-analysis. Neurosci Biobehav Rev 35, 715-728.

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