HUMAN FACES ARE SO VARIABLE BECAUSE WE EVOLVED TO LOOK UNIQUE

The amazing variety of human faces -- far greater than that of most other animals -- is the result of evolutionary pressure to make each of us unique and easily recognizable, according to a new study by University of California, Berkeley, scientists.

Our highly visual social interactions are almost certainly the driver of this evolutionary trend, said behavioral ecologist Michael J. Sheehan, a postdoctoral fellow in UC Berkeley's Museum of Vertebrate Zoology. Many animals use smell or vocalization to identify individuals, making distinctive facial features unimportant, especially for animals that roam after dark, he said. But humans are different.

"Humans are phenomenally good at recognizing faces; there is a part of the brain specialized for that," Sheehan said. "Our study now shows that humans have been selected to be unique and easily recognizable. It is clearly beneficial for me to recognize others, but also beneficial for me to be recognizable. Otherwise, we would all look more similar."

"The idea that social interaction may have facilitated or led to selection for us to be individually recognizable implies that human social structure has driven the evolution of how we look," said coauthor Michael Nachman, a population geneticist, professor of integrative biology and director of the UC Berkeley Museum of Vertebrate Zoology.

The study will appear Sept. 16 in the online journal Nature Communications.

In the study, Sheehan said, "we asked, 'Are traits such as distance between the eyes or width of the nose variable just by chance, or has there been evolutionary selection to be more variable than they would be otherwise; more distinctive and more unique?'"

As predicted, the researchers found that facial traits are much more variable than other bodily traits, such as the length of the hand, and that facial traits are independent of other facial traits, unlike most body measures. People with longer arms, for example, typically have longer legs, while people with wider noses or widely spaced eyes don't have longer noses. Both findings suggest that facial variation has been enhanced through evolution.

Finally, they compared the genomes of people from around the world and found more genetic variation in the genomic regions that control facial characteristics than in other areas of the genome, a sign that variation is evolutionarily advantageous.

"All three predictions were met: facial traits are more variable and less correlated than other traits, and the genes that underlie them show higher levels of variation," Nachman said. "Lots of regions of the genome contribute to facial features, so you would expect the genetic variation to be subtle, and it is. But it is consistent and statistically significant."

Using Army data

Sheehan was able to assess human facial variability thanks to a U.S. Army database of body measurements compiled from male and female personnel in 1988. The Army Anthropometric Survey (ANSUR) data are used to design and size everything from uniforms and protective clothing to vehicles and workstations.

A statistical comparison of facial traits of European Americans and African Americans -- forehead-chin distance, ear height, nose width and distance between pupils, for example -- with other body traits -- forearm length, height at waist, etc. -- showed that facial traits are, on average, more varied than the others. The most variable traits are situated within the triangle of the eyes, mouth and nose.

Sheehan and Nachman also had access to data collected by the 1000 Genome project, which has sequenced more than 1,000 human genomes since 2008 and catalogued nearly 40 million genetic variations among humans worldwide. Looking at regions of the human genome that have been identified as determining the shape of the face, they found a much higher number of variants than for traits, such as height, not involving the face.

Prehistoric origins

"Genetic variation tends to be weeded out by natural selection in the case of traits that are essential to survival," Nachman said. "Here it is the opposite; selection is maintaining variation. All of this is consistent with the idea that there has been selection for variation to facilitate recognition of individuals."

They also compared the human genomes with recently sequenced genomes of Neanderthals and Denisovans and found similar genetic variation, which indicates that the facial variation in modern humans must have originated prior to the split between these different lineages.

"Clearly, we recognize people by many traits -- for example their height or their gait -- but our findings argue that the face is the predominant way we recognize people," Sheehan said.

Just Saying That Exercise Helps Neuropathy Doesnt Necessarily Make It So

Today's post from nursing.onclive.com (see link below) again promotes exercise as a way of reducing neuropathy symptoms but in this case, the evidence seems a little thin. By testing a group of cancer patients with neuropathy as a side effect, they found that walking and other general exercise prevented the symptoms from worsening, especially in older patients. I would suggest that moderate exercise will help older patients feel generally better anyway than sitting or lying for long periods of time but they'll need to provide much more specific evidence to prove that neuropathic symptoms can be reduced by a graduated walking course. In this case, I would suggest that with this sort of patient, there are far too many variables to come to the conclusion that exercise is more effective in reducing or limiting nerve damage symptoms in older people. That said, there is a general consensus among doctors that regular exercise will improve neuropathy, or at least stop it getting worse but in this case, I feel too much is being assumed from too little data.

Walking and Resistance Training Eases CIPN, Especially Among Older Patients
LAUREN M. GREEN @OncNurseEditor Wednesday, July 20, 2016

Patients undergoing chemotherapy prescribed a formal exercise program experienced less chemotherapy-induced peripheral neuropathy (CIPN), and the finding held true across all chemotherapy regimens tested. The effect was strongest in older patients, according to findings from a nationwide randomized controlled trial reported at the 2016 ASCO Annual Meeting.

CIPN is a highly prevalent and severe side effect of certain chemotherapy types, such as platinums, taxanes, and vinca alkaloids, affecting more than 50% of patients receiving these therapies. Nevertheless, “there are currently no established treatments for CIPN—despite 50 randomized clinical trials—testing the efficacy of drugs to prevent or treat it,” explained lead study author Ian Kleckner, PhD.

Kleckner, a research assistant professor at the University of Rochester Medical Center, and colleagues performed a secondary analysis of a subset of 314 sedentary patients receiving taxane-, vinca alkaloid-, or platinum-based chemotherapy derived from a larger, phase III, national, randomized controlled trial (N = 619).

The majority of patients were women (92%), and 78% had breast cancer. They were randomized to chemotherapy alone or chemotherapy plus exercise. Patients randomized to the EXCAP arm (Exercise for Cancer Patients) which is a personalized, 6-week, home-based, moderate-intensity progressive program, were prescribed a daily walking regimen (eg, steps per day), supplied with pedometers, and also given a set of resistance bands to perform specific exercises.

Walking and resistance exercises were recommended for the control group. They did not receive any formalized support; however, control participants were given the exercise kit at the end of the study.

The investigators used patient self-report of tingling and numbness at baseline and after the intervention, rated on a 0-10 scale with 10 being the worst level of CIPN. In the EXCAP arm, CIPN was reduced compared with controls, with an effect size of 0.26 (P = .06), and the finding was independent of other variables, such as gender, BMI, and cancer stage. However, age was a moderating variable.

“We found that exercise was more effective for older patients,” said Kleckner. “Older patients in the control arm experienced a large increase in CIPN after 6 weeks of chemotherapy, whereas older patients in the experimental exercise arm had a very small, if any, increase in CIPN.”

Kleckner said that based on these findings, he and colleagues hope to expand their research. “What we’d like to do now is design a randomized clinical trial testing exercise against chemotherapy alone, where CIPN is the primary outcome. Only one trial to date has looked at this, and it was very small—60 patients.”

He hopes researchers can identify biomarkers in the brain circuitry or signals of the role inflammation may play to help better identify who is most at risk for CIPN.

Over the next few years, Kleckner would like to see this research continue to “scale up, so we can better learn about the effectiveness of exercise, understand what dose/intensity of exercise is important, what type of exercise, and who responds best to exercise … we’re hoping for an exercise prescription, instead of the generic ‘please exercise.’”

Kleckner I, Kamen CS, Peppone LJ, et al. A URCC NCORP nationwide randomized controlled trial investigating the effect of exercise on chemotherapy-induced peripheral neuropathy in 314 cancer patients. J Clin Oncol. 2016; 34 (suppl; abstr 10000).

http://nursing.onclive.com/web-exclusives/walking-and-resistance-training-eases-cipn-especially-among-older-patients

Why Does Neuropathy Make Us So Damned Tired

Today's post from neuropathyjournal.org (see link below) tries to explain why many people living with neuropathy (especially autonomic neuropathy) become progressively more tired as the years go on. There's no easy answer and there can also be many other reasons why fatigue and weakness start to affect our lives so strongly but for many people, along with degradation of nerve fibres, comes muscle and mental fatigue and it can be very difficult to live with. LtCol Richardson does a good job of explaining the process but also offers some helpful tips to help us cope with and improve our tiredness levels. Worth a read.

Fatigue in Peripheral Neuropathy 
By LtCol Eugene B Richardson, USA (Retired) BA, MDiv, EdM, MS9

Unfortunately fatigue is a central part of many neuropathies and especially the immune mediated neuropathies. It is central to many other chronic illnesses that affect the body’s immune system. The causes are often complex and many.

Dr. Scott Berman, in his book Coping with Chronic Neuropathy notes in chapter VIII “Dealing with Fatigue and Insomnia” that this symptom is one of the most difficult and challenging for the neuropathy patient. Dr. Berman is a Psychiatrist, a member of the Board of Directors of the NSN and a Medical Advisor. Scott lives with untreatable CIDP.

He notes:

…that in one study looking at fatigue in autoimmune neuropathy 80% of 113 patients had severe fatigue. The fatigue was independent of motor or sensory symptoms and was rated as one of the top three most disabling symptoms. (“Fatigue in Immune-Mediated Polyneuropathies,” Neurology 53: 8 November 1999, I.S.J. Merkies, et al).

For decades in living with untreated Chronic Inflammatory Demyelinating Polyneuropathy (CIDP), Autonomic Neuropathy (AN) and Progressive Polyneuropathy due to exposure to Agent Orange in Vietnam, I can attest to the facts noted above. While other major symptoms respond to treatment with Immune Globulin (IVIg), the symptom of severe fatigue continues as one of the symptoms that responds only temporarily to the infusions followed by several days of total fatigue following infusion and then with some lessening until the next infusion.

Dr. Norman Latov in his book “Coping with Peripheral Neuropathy”, states what I have heard other neurologists share, that the fatigue we feel, first appearing as weakness, increases as the weakness (or damage) of motor nerves expands. At this point with only a few muscles doing the whole job of lifting a leg or arm or carrying on autonomic functions, the body becomes weak and eventually extreme fatigue occurs. Think of a young child who tires easily because the muscles and nerves are not fully developed and only a few underdeveloped nerves or muscles are doing the job of moving!

On the other hand, to state the obvious, pain in some neuropathies does not help us sleep. Neuropathy patients must seek medical help in finding medications or other options which works for them. The medical practitioners have increased their knowledge in recognizing the reality of neuropathic pain. These strange symptoms from damaged peripheral nerves are present in sensory neuropathies. It is become less common for these patients to be told that it is all in their ‘head’ and are finally getting the help they need.

Impact on family and friends:

Families and friends, as we all have learned, may not understand this reality since we “look so good” and may even believe/suggest that you are just lazy or unmotivated or worse. The best thing you can do for them is to have them watch the DVD Coping with Chronic Neuropathy which will be an education about the impact of any neuropathy on our lives.

Educating yourself about neuropathy:

At any rate, fatigue is something we struggle with every day and often regulates/determines our daily activities.

While fatigue in neuropathy and other chronic illnesses is not fully understood by the experts, from a practical standpoint, here is what I have learned to do or not do in coping with fatigue. If you have found other things that help, send us a message and we will add it to the list.

1. DO NOT think negatively about fatigue, thus feeling guilty about your fatigue. Go take a nap! (See DVD “Coping with Chronic Neuropathy”).

2. Learn when your “fatigue” periods occur, as these often establish a pattern at certain times of the day. Then go lay down and stop moaning about it, as it is what it is until it isn’t.

3. I have learned that you do not even have to actually “sleep”, but just allowing your body to rest/stop for an hour takes care of the exhaustion as the body recovers. But whatever works for you, do it without guilt or apology.

4. For nighttime, have a standard bedtime routine in preparing for sleep that tells your body that it is time to sleep.

5. Do not eat a large meal just before bedtime or take a stimulant that keeps you awake or might interfere with sound sleep (i.e. caffeine, for some alcohol).

6. Do consider drinking a glass of milk as for many this encourages the body to sleep.

7. Do consider one of those special recordings of quiet music or rain falling or similar if it helps.

8. Do consider using a ticking clock if that helps. As a child in the 40s I got my best sleep on the floor in front of the big radio in the living room listening to Dragnet or was it the Lone Ranger, maybe the Big Story. Today most TV programs have the same effect, sleep! Pun intended.

9. Muscle spasms and/or restless leg can make sleeping difficult and rob you of needed sleep. Speak to your doctor and have tests done for calcium, salt, potassium levels and other deficiencies which can make it difficult for muscles to work properly. This is especially true if you are on a diuretic which can empty your body of needed minerals. Getting up and having a glass of orange juice worked for my mother and works for me. If the lack of something is not the problem, have the doctor find out what may be causing these muscle problems. There are also medications to help prevent these muscle spasms and cramps for they are very common in neuropathy.

10. I have found that if I wake up with my mind creating solutions to an issue or writing poetry (happens) and not able to sleep, I go to another room or go do some work on my computer (write out the solution or poetry) until I begin to feel sleepy again. It works for me.

11. For some insomnia is a real curse. There are medications that one can use as Dr. Scott Berman mentions in his book, so speak to your doctor. Frankly, I would work on natural solutions first and be creative to see what works for you. But if ALL else fails these medications may help and be a heaven sent blessing.

12. My Nurse told me that many patients with this effect of a chronic illness, take Folic Acid and it is known to help. So you many want to speak to your doctor in this regard.

13. Dr. Erika Schwartz, M.D. (national leading expert on wellness) suggests that patients with extreme fatigue have the physician check your basal metabolic rate and your thyroid function. Low thyroid is a common cause of fatigue. So speak to your doctor in this regard.

14. So what do you do or not do that helps? Send it to us and we will enter it here!

DISCLAIMER: The information in this article and on the website or the links or in the guidance provided is intended to be educational and informative and not medically prescriptive or diagnostic. All patients are encouraged to consult with their own medical doctor when considering any this information.

Copyright – 2014-2015 Network for Neuropathy Support, Inc., 501c3, dba as Neuropathy Support Network. This article or its contents may be reprinted or published for educational purposes as long as the printing or publishing is not for profit and acknowledgement is granted the author.

https://neuropathyjournal.org/fatigue-in-peripheral-neuropathy/