Do adolescents really grow more in the summer?

Get to Know more about Your Kid’s Growth Spurts

Everything you need to know about your kid's growth spurts flyer

6 Signs Your Kid Is Having A Growth Spurt

Could it be the warm summer months, lots of sunshine, less stress and more sleep that causes seemingly ‘more growth’ in the summer for adolescents? Perhaps. But whatever the reason may be, your pre-teen or teen is making big gains in his/her body.

And summer is a great time for annual doctor check-ups and sports physicals. Plus keep an eye on their spines when they don a swimsuit. Do you notice a hump in their ribs when they bend over or does one of their shoulder blades look like it is ‘winging out’? If so, definitely follow up with your pediatrician for a scoliosis screening. It is always best to catch the curve while it is small so that the best care can be given. But whatever you do , don’t ‘wait and see’ if the curve in their spine will straighten out on its own. There are several conservative treatment options available to your adolescent to monitor, halt and/or reverse the scoliotic curve: no matter how small or big!

Inquire below for more information about conservative scoliosis treatment options :

Contact us today!

Want to know a way to decrease inflammation naturally and holistically WITHOUT the use of medications?


fruit cherries
Photo by Lisa Fotios on

Cherries! Or more specifically, Tart Cherry Juice.

All it takes is simply 2 tablespoons of tart cherry juice FROM concentrate, preferably before bedtime ( I’ll explain the ‘why’ for that in another post) and you will see and feel the difference this delicious fruit can make in your body.

The following are excerpts from the insightful book, ‘Taming Pain: Lessons from the Trenches” by Cheryl Wardlaw.Get the book here

“Research shows that cherries reduce inflammatory chemicals by as much as 25% (after only 28 days of eating them)  without having a negative effect on blood sugar or insulin levels.  Even better, these gains are sustained for over a month after you stop eating cherries (although why would you stop eating cherries?!) Cherries are packed with antioxidants and anti-inflammatory substances, including anthocyanin, quercetin and melatonin, and assist the body in producing glutathione (the main anti-inflammatory for the brain.)”

Anyone who has gout will most likely tell you that they already know the benefits of drinking tart cherry juice as it helps to decrease gout symptoms. That is because the anthocyanin in cherries reduces blood urate levels by 15% in as little as 3 days. Turns out that “cherries have the HIGHEST levels of anthocyanin of any food (blueberries don’t have any) and specifically block COX I and II (inflammatory chemicals., just like arthritis medication. Anthocyanins are more effective than vitamin C or E and AS EFFECTIVE as Naproxen, Ibuprofen or Aspirin WITH NO BAD EFFECT ON YOUR STOMACH! Note: for kidney health you should not take over 5000 NSAIDs and 1000 acetaminophen tablets in your lifetime!”

To sum it up here’s what anthocyanin does for you:

“Lowers urate (uric acid) levels in the blood stream to control gout

Acts an anti-inflammatory on par with NSAIDs

Suppresses production of pro-inflammatory cytokines

Suppresses growth factors 

Protects cell membranes”

In my next blog, I will talk about more AMAZING things that cherries can do for your health.

Cherry season is nearly here, so plan on indulging in them!

And in the meantime, go buy some Tart Cherry Juice FROM CONCENTRATE, pour 2 tablespoons into a cup and cheers!

(Caution: cherry juice is a natural blood thinner. If you take prescription blood thinners, then please talk to your doctor about your medications if they need to be adjusted)

Breaking news! An update on Melissa’s story: ” I won’t wait and see anymore”

Update on Melissa’s Story

Melissa and her daughterIn February, I posted a story about my sister, and her journey with scoliosis. (If you haven’t had a chance to read it, then click here to catch up before you read about her progress)  Melissa’s story

Melissa went to her annual check-up this past month and got some encouraging news! Last April, prior to beginning her Schroth therapy in the Fall, She went to her annual physical exam and was saddened to learn that she had ‘shrunk’ nearly 2 inches! She had been 5’8″ since she hit maturity as an adolescent, and when she learned she had lost nearly 2 inches in height:  it was not good news (especially since that meant she would now be the same height as her older and shorter sister!)

But all kidding aside, she knew that this change in height really meat that her scoliosis may be getting worse.

Fast forward 6 months and she began the Schroth physical therapy at the Paley Institute in West Palm Beach, FL alongside with her youngest daughter, who also has scoliosis.

They both went to many treatment sessions and enjoyed it so much that they had Schroth wall bars built and installed in their home for them to use on a daily basis. They also have the placement pads and do the exercises as recommended by their physical therapist.

This past month Melissa went again to her annual physical exam and her doctor measured her height. Guess what? She is now back to her usual 5’8″! She was so excited that she immediately called to tell me her good news. She attributes the positive change to doing the prescribed specific scoliosis exercises (PSSE) and learning her curve.

And as if that wasn’t enough good news: there’s more! Her daughter, went in for a DIERS scan and it found that her curve decreased 7 degrees! The DIERS Formetric 4D is a light-optical scanning method which projects a line grid on the back of the patient which is recorded by an imaging unit.

So what’s the ‘take away’ message here? Schroth Therapy works for improving posture and decreasing scoliotic curves! But it only works if you put the effort into it. Both Melissa and her daughter are motivated for change !

If this story speaks to you or someone that you know who may need to hear this, then please contact me to find out how I can help improve your scoliotic posture.

“Nothing motivates you like movement. If you need motivation, get moving.”  –Christy Wright

Contact me today!

I bet you’d never guess that the nagging pain in your hip could be coming from somewhere else…

Do you have hip pain or pain in your thigh that just won’t go away?

(Now if you do have hip degeneration and have been told you need a hip replacement, then you probably have more going on than this article pertains to)

Ever thought that there may not be anything wrong at all with your hip? It may in fact be  ‘referred pain.’

What is referred pain? It is pain in an area of your body that can often be some distance away from the actual stressed tissue.

One good example is sometimes hip pain can be diagnosed as hip bursitis: inflammation of the bursa (fluid-filled sac near a joint) at the part of the hip called the greater trochanter. When this bursa becomes irritated or inflamed, it causes pain in the hip. Yes, hip pain truly can be coming from your hip, but when you have tried to get rid of it with traditional therapies or injections and it still is there,  then the source may be coming from somewhere else…and it may be nerve root referred pain. 

Check out this map of the dermatomes of the body that depicts where nerve roots refer to: 

Mapping the Spinal Cord Color Chart

The following excerpt is from ‘Taming Pain: Lessons from the Trenches.”- Second Edition 2013 by Cheryl F. Wardlaw, PT MMSc, CFMT :

“A nerve root is the part of the nerve that comes off of the spinal cord and goes out the hole between two vertebrae.

Each nerve root has some fibers mixed in from the nerve root above and below, so it’s not EXACT. Each nerve root, when stressed, can cause pain in a predictable path. It will cause weakness in predictable muscles. Let’s take the L4 nerve root for example. Let’s say you have pain on the side of your hip and in the front of your thigh. The muscles that pick up your big toe (L4) and straighten your knee (L3& L4) are weak. I would sure need to look at what could be irritating the L4 nerve root!

Could it just be hip bursitis? Doubtful. Hip bursitis doesn’t make your big toe weak. Could it be 5 things: hip bursitis, a pulled muscle in your thigh, some knee arthritis, a bunion on your big toe and low magnesium? Well, it could be, but I would still have to rule out the L4.

Things that stress a nerve root:

If we decide that a nerve root is squawking, and we know which nerve root, the question still remains, what is irritating the nerve root? So here goes:

The Facet joint: the joints in your spine are called facet joints

The Nerve Root: comes out of the hole in front of the facet joints. Changes at the facet joint can decrease the size of the space and put pressure on the nerve. Inflammation will be the result.

The Disc: The spacer between the vertebrae is the disc. If the disc shrinks down (degeneration) the bones will get closer together. The size of the opening will decrease and the nerve will be compressed and will inflame. If the disc bulges back, the same thing happens.

The Spinal Canal: The space that the spinal cord runs through is called the canal. Across time, bone can build up inside the canal and make less room for the nerve root. This condition is known as spinal stenosis. The nerve will be compressed and will inflame.

Now that we know where it is, ( Let’s stick with L4 as our suspect), what might be causing it ( let’s choose a locked facet) and that the nerve root is inflamed, our job is as simple as a game of CLUE : Colonel Mustard, in the library, with the candlestick! Referred pain patterns help me figure out where I should be working!

If your therapist or doctor are only treating your symptoms, and not searching very actively for where the pain is coming from, then you will be hurting a very long time.”

See how maybe your hip pain isn’t really coming from the hip itself, but rather may be coming from your back? Contact me today to see how I can help solve your pain puzzle and get rid of the nerve culprit! 


5 Things You Can Do to Avoid ‘Weekend Warrior’ Injuries

Lawn mower mowing grass
Photos by

Between work, family commitments, and running errands, it’s understandable why weekend warriors cram all their physical activity on Saturday and Sunday. And bonus if the weather is beautiful (as it was here in Tallahassee this weekend).

Unfortunately, this pattern of 5 days of inactivity, and being active on the weekend often leads to injury.

The most common types of injuries seen in weekend warriors are:

Muscle strains such as hamstring strains

Ligament sprains, most commonly in the ankle

Tendonitis, especially in the Achilles

Low back pain

Shoulder Pain

active athlete dribbling a basketball

To decrease your chances of injury, there are some things you can do. The biggest step you can take is to avoid going from no activity to full out competition. Try to maintain a basic level of fitness through general aerobic activity, strengthening, and stretching throughout the week. If you know what type of sport you’ll be participating in, adding in some sport-specific conditioning is a good idea. 

In addition to maintaining a basic level of fitness, here are a few other tips specifically for the weekend warrior:

  1. Build your activity level slowly
    If you’ve taken a layoff over the winter, build up slowly to your first 5k, or the spring softball season.
  2. Give yourself time for a proper warm up
    A dynamic warm up is best, including some jogging or other aerobic activity to get your heart rate up, along with some high knees, braiding, butt kicks, or toy soldiers will get your body ready for activity.
  3. Stretch when you’re done
    Research has shown that static stretching before activity probably doesn’t have much benefit, but stretching after has been shown to reduce soreness and help recovery.
  4. Make sure your technique and equipment are up to par
    Poor equipment can put you at higher risk for injury. If your technique is off, especially in sports like golf or tennis, you can be at higher risk for injury. A visit with your physical therapist or coach can help correct issues.
  5. Don’t push through pain
    Some soreness after an increase in activity is normal, but if it doesn’t go away, gets worse, or is severe, get it checked out.

woman in grey shirt holding brown cardboard box

If you’re having pain, suffered an injury, want help designing a training program to get you ready to compete, or just want a physical to make sure you’re ready for activity, a visit with a physical therapist is a good idea.

So go ahead and give me a call today to get back to feeling healthy and pain free and then you can live your life to the fullest!



High Hopes Realized for Female Entrepreneur!

Joy Smith standing next to her logo in her clinic

‘High Hopes’ Realized

I love Panic! At the Disco’s song, ‘High Hopes’, as I have dubbed it my ‘theme song’ these past several months while I plugged along creating my physical therapy clinic:

“I had to have high high hopes for a living. Didn’t know how but I always had a feeling.”  (Check out their video if you want to get that song in your head )  Panic! At the Disco- High Hopes

Many years of building a community of clients and contemplating just how to do this thing called a business, finally culminated into a fabulous celebration last night. The  open house to my brand new PT clinic, Joy of Therapy, was a smashing success!

 I truly enjoyed every minute of it and am so very grateful for the many clients, friends and family that took time out of their day to come and support my “dream come true!” (We were all having such a good time, that we forgot to take pics of everyone that came to the open house. Oops! But check out the good ones below.)

The food was DELICIOUS (thank you to Brandy L.,  Sarah H. , Tasty Pastry, Publix and Josey V. ) , the decor GORGEOUS ( thank you to the talented, Karyn Tarmey), set- up and serve went SMOOTHLY (thank you to my mom and dad, Brandy and Kylie L.) and hey, I looked pretty good too! (thanks to my stylists, Jillian Visconti (hair stylist) and Marianne Brooks with Cabi). It takes a village to pull this off, and my heart is filled with gratitude for all of you.

The clinic is truly reflective of ‘me’ and how I believe that physical therapy should and needs to be delivered: efficient, thoughtful, caring, valuable to you, your time and your money and most of all, joyful.

So if you haven’t already come in for your evaluation, then what are you waiting for ?! I am here and ready to serve your PT needs whenever they may arise for you. Here I come Tallahassee!

Sleeping on your side may be the best position for a healthy brain

close up photography of woman sleeping
Photo by Bruce Mars on

Recent research has found that “the brains of mice who slept on their side removed waste the most efficiently. Brain waste can often contain beta-amyloid proteins, which make up the plaque commonly found in Alzheimer’s patients. By clearing away these proteins , researchers believe that the brain protects itself from developing certain neurological diseases.”

Sleeping on your side may be the best position for your brain


Melissa’s story: “I won’t ‘wait and see’ anymore”

Melissa’s Story

Melissa smilingMelissa’s story probably began like most of yours. She was a healthy child who stayed active in extracurricular activities and enjoyed just being a kid. Then, during adolescence in middle school, she was given a surprising diagnosis: she had scoliosis. How she dealt with it as she grew into adulthood and finally found answers, strength and relief through the use of Schroth physical therapy is truly inspiring.(Spoiler alert: she’s my sister)

I am a 42 year old, health-conscious woman married to a loving husband with two amazing daughters, whom I enjoy homeschooling. I have a good life and try to live every moment to its fullest. But what most people may be surprised to hear is that for 20 years I have lived with daily, achy and often sharp pain in my back due to scoliosis that was diagnosed when I was a teenager. I exercise daily, which can include Pilates, walking and strength training. Thankfully, I have been able to avoid taking prescription pain pills. But some days are really hard to get through due to pain.

I have silently struggled with my pain and diagnosis as best I could, and it hit me hard a couple of years ago, when my youngest daughter was also diagnosed with scoliosis. It was then that I had had enough and wanted real solutions since I didn’t want her story to be like mine. 

When I  was diagnosed with scoliosis during a middle school health screening, I had no  pain or symptoms. No one in my family had scoliosis, so no one was looking for it. It was recommended to my parents that I see a chiropractor to help. He adjusted me, and my clearest memory of that experience was leaving there crying in tears due to the pain of the adjustment. It hurt so bad! (FYI: I now know that no one with scoliosis should be manipulated since the vertebral bodies of the spine grow irregular). I was told by my doctor to ‘wait and see’ how the curve would progress.

I went on to high school and college with no pain or limitations, and yet unbeknownst to me, my curve was only getting worse. By the age of 22, I was working in hotel management, and my job required me to be on my feet all day long. I loved that job, but oh the pain in my back had set in, and it hurt! So off I went with my parents for x-rays at Miami Children’s Hosptial and to see the best doctor at the time for scoliosis. He said that I now had an ‘S’ curve that was 40 degrees and surgery was not recommended, unless I wanted it for cosmetic reasons. Once again I was told to ‘wait and see’ and hope that my rib cage wouldn’t puncture a lung! I did try traditional physical therapy with minimal relief.

When I was in my 30’s, after I had given birth to my beautiful daughters, I went in again for x-rays since the pain was only getting worse. This time the curve had progressed to 48 degrees and now borderline for surgery. Guess what? I was told to ‘wait and see’.

So when my youngest daughter got the  diagnosis of scoliosis, I wasn’t going to ‘wait and see’ anymore. As a toddler, I intuitively knew that something wasn’t quite right with the way she walked. I took her to a pediatric orthopedic doctor, a podiatrist and countless visits to the pediatrician to try and figure out what was going on with her legs and feet. No one suspected scoliosis, not even me.

By the time she was 5, she was in special shoes with a lift and running was sometimes awkward. My sister, who is a physical therapist, looked at her and noticed that one hip was higher than the other and tried manual therapy which helped a little. She looked again months later ( since she doesn’t live near us) and noticed the same thing and a slight curve in her back. She recommended I go to an orthopedic doctor for evaluation. There she was diagnosed with mild scoliosis of 10 degrees, and you can imagine what words I heard next:  ‘wait and see.’

This time, I wasn’t going to tolerate that phrase and immediately called my sister for her professional opinion. This was a defining moment in our conversation: she told me there was help with the Schroth Method. It is a unique 3-dimensional treatment approach that helps to elongate, de-rotate and strengthen the scoliotic spine. It aims to halt or even reverse the progression of the spinal curve. What a relief to hear those new words!

By this time, my sister had researched the Schroth Method and was training to be a certified physical therapist with this specialty. I too researched this myself and discovered that it is an intense certification and to only go to those who have this training and understanding of the scoliotic spine . She was able to connect me with the Paley Institute where I met Dr. Feldman. For the first time in my life I was not told to wait and see!’ He agreed that the Schroth Method works and referred me to Lisa Ritze, PT, a certified Schroth-Barcelona physical therapist.  She and other trained PT’s in this method have been working with both myself and my daughter since October 2018. We are very compliant with keeping up with the exercises and therapy.

It’s so important to always go to therapy for tune-ups since scoliosis tricks you into thinking that your spine is straight when it is so not! Plus you need to continue through puberty since growth spurts bring on big changes in the spine.

Over these past several months, physical therapy with the Schroth Method has changed mine and my daughter’s lives dramatically. I now have better tools to manage my back pain, and I am so glad that my daughter’s spine won’t have the opportunity to get to where my spine did. My daughter performs her daily exercises at home now and she knows the tools to help her back when she has pain or needs lengthening. It has also given her new and improved strength that she uses on the swim team! She said to me the other day, this therapy makes me stronger, gives me space in between my ribs and makes my back feel so good!”

My x-rays last year showed an upper curve of 53 degrees and a lower curve of 51 degrees. I still do not want surgery and my new, well-informed doctor, is confident that I won’t need surgery either. I know that at my age I won’t be able to make big changes in the curve, but I can stop the progression and avoid early arthritis by doing the Schroth Method exercises .

I am so grateful for the conservative treatment of scoliosis through the Schroth Method! I would have given anything to know about this method back in the 1990’s, but I know now and will never look back. I am also thankful for the time, advice, dedication, passion, love and God-given talent that my sister has as a physical therapist.

Oh, and did I mention that her name is Joy Smith, PT?! Yep, she’s the one you need to go and see right now if you have scoliosis! I wish she lived closer so I could come to her new clinic as often as I wanted to do this therapy with her.

I am here to tell you with full confidence that this method works and to not waste another day in pain!

More importantly, don’t let your child with scoliosis become a ‘wait and see’ adult in pain.

Run, don’t walk, to get your Schroth physical therapy evaluation today to see how it can make a difference in your life! –Melissa


Do you have numbness or tingling in your hands?

Research has proven that the use of neurodynamic techniques in conservative treatment for mild to moderate forms of carpal tunnel syndrome has significant therapeutic benefits.

I can help you manage these symptoms and get real relief with some innovative physical therapy techniques. Read on…

ballpen blur close up computer
Photo by Pixabay on


Clin Rehabil. 2018 Oct 11:269215518805213. doi: 10.1177/0269215518805213.

Is manual therapy based on neurodynamic techniques effective in the treatment of carpal tunnel syndrome? A randomized controlled trial.

Wolny T1Linek P1.


The aim of this study was to evaluate the efficacy of manual therapy based on neurodynamic techniques in conservative treatment of carpal tunnel syndrome.


Randomized controlled trial.


Several medical outpatient clinics in the south of Poland.


The study included 103 patients with mild and moderate carpal tunnel syndrome (mean age = 53.95, SD = 9.5) years, who were randomly assigned to a neurodynamic techniques group (experimental group, n = 58) or a group without treatment (control group, n = 45).


Neurodynamic techniques were used in the experimental group. Treatment was conducted twice weekly (20 sessions). Control group did not receive treatment.


Nerve conduction study, pain, symptom severity and functional status of Boston Carpal Tunnel Questionnaire, and strength of cylindrical and pincer grips were assessed at baseline and immediately after treatment (nerve conduction study one month after treatment).


Baseline assessment revealed no group differences in any assessed parameters (P > 0.05). There were significant differences between groups after treatment, including nerve conduction (e.g. sensory conduction velocity: experimental group: 38.3 m/s, SD = 11.1 vs control group: 25.9 m/s, SD = 7.72, P < 0.01). Significant changes also occurred in pain (experimental group: 1.38, SD = 1.01 vs control group: 5.46, SD = 1.05, P < 0.01), symptom severity (experimental group: 1.08, SD = 0.46 vs control group: 2.87, SD = 0.68, P < 0.01), and functional status (experimental group: 1.96, SD = 0.64 vs control group: 2.87, SD = 1.12, P < 0.01). There were no group differences in strength ( P > 0.05).


The use of neurodynamic techniques in conservative treatment for mild to moderate forms of carpal tunnel syndrome has significant therapeutic benefits.

Coming soon! Free Scoliosis Screening Clinic

x- ray of a spine with scoliosis Have you or your child been told you may have scoliosis? Have you been to a surgeon or specialist and told to ‘wait and see’ how your curve progresses in a year or so? Well there are real solutions to help you right now!

Come on out to our FREE scoliosis screening clinic next month to see how we can help your back improve and get you feeling stronger and straighter.

There are specific scoliosis exercises that truly can help to either improve, halt or reverse the progression of the curve in your spine.

Joy Smith, PT is the ONLY scoliosis specialist in the Florida Panhandle who is a Schroth-Barcelona C1 certified physical therapist.

Next scoliosis screening clinic is slated for February so stay tuned for date and time!

girl standing with Schroth poles

Ever wonder why you may not sleep well the first night at a new place?

Turns out that one side of your brain stays ‘vigilant’ to protect you!

close up photography of woman sleepingPhoto by bruce mars on

Night Watch in One Brain Hemisphere during Sleep Associated with the First-Night Effect in Humans


d Interhemispheric asymmetry in sleep depth occurs for the first night in a new place

d This interhemispheric asymmetry occurs in the default-mode network


Masako Tamaki, Ji Won Bang, Takeo Watanabe, Yuka Sasaki


In Brief

Tamaki et al. find that when humans sleep in a novel environment, the default-mode network in one hemisphere is kept more vigilant to wake the sleeper up as a night watch upon detection of deviant stimuli. The regional interhemispheric asymmetric sleep in a novel environment may play a similar protective role to that in marine mammals and birds.

d The less-asleep hemisphere shows increased vigilance in response to deviant stimuli

d One brain hemisphere may work as a night watch during sleep in a novel environment

Tamaki et al., 2016, Current Biology 26, 1190–1194 May 9, 2016 a 2016 Elsevier Ltd.


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Current Biology


Night Watch in One Brain Hemisphere during Sleep Associated with the First-Night Effect in Humans

Masako Tamaki,1 Ji Won Bang,1,2 Takeo Watanabe,1 and Yuka Sasaki1,*
1Department of Cognitive, Linguistic, and Psychological Sciences, Brown University, 190 Thayer Street, Box 1821, Providence,
RI 02912, USA
2Present address: Cognition & Brain Science, School of Psychology, Georgia Institute of Technology, 831 Marietta Street NW, Atlanta, GA 30318, USA


We often experience troubled sleep in a novel environment [1]. This is called the first-night effect (FNE) in human sleep research and has been re- garded as a typical sleep disturbance [2–4]. Here, we show that the FNE is a manifestation of one hemi- sphere being more vigilant than the other as a night watch to monitor unfamiliar surroundings during sleep [5, 6]. Using advanced neuroimaging tech- niques [7, 8] as well as polysomnography, we found that the temporary sleep disturbance in the first sleep experimental session involves regional interhemi- spheric asymmetry of sleep depth [9]. The interhemi- spheric asymmetry of sleep depth associated with the FNE was found in the default-mode network (DMN) involved with spontaneous internal thoughts during wakeful rest [10, 11]. The degree of asymme- try was significantly correlated with the sleep-onset latency, which reflects the degree of difficulty of fall- ing asleep and is a critical measure for the FNE. Furthermore, the hemisphere with reduced sleep depth showed enhanced evoked brain response to deviant external stimuli. Deviant external stimuli detected by the less-sleeping hemisphere caused more arousals and faster behavioral responses than those detected by the other hemisphere. None of these asymmetries were evident during subsequent sleep sessions. These lines of evidence are in accord with the hypothesis that troubled sleep in an unfamil- iar environment is an act for survival over an unfamil- iar and potentially dangerous environment by keep- ing one hemisphere partially more vigilant than the other hemisphere as a night watch, which wakes the sleeper up when unfamiliar external signals are detected.


Does sleep disturbance caused by an unfamiliar environment, that is, the first-night effect (FNE), have only negative effects?

It has been suggested that a function of partial sleep such as uni- lateral hemispheric sleep in some birds and marine mammals is a protective mechanism to compensate for risks during sleep [5, 6]. This led us to ask whether the FNE is involved in some type of interhemispheric sleep to be vigilant in one brain hemi- sphere in humans as a protective mechanism.

In experiment 1 (see Supplemental Experimental Proce- dures), we tested whether a regional interhemispheric asym- metry occurs with the FNE using an advanced neuroimag- ing technique that combines magnetoencephalography (MEG), structural MRI, and polysomnography (PSG) in the sleeping brain. We investigated slow-wave activity (SWA), which is a spontaneous brain oscillation (1–4 Hz) in non-rapid eye move- ment (NREM) sleep. The reason that we focused on SWA is that it is the only sleep characteristic that reflects the depth of sleep [9, 12] and is supported by cross-species studies of local sleep including those for mammals and birds. Since SWA in hu- mans originates in cortical regions including the brain network such as default-mode network (DMN) [10, 11, 13], we hypothe- sized that the regional interhemispheric SWA occurs in brain networks while the FNE occurs. To test this hypothesis, we measured SWA from four brain networks (including the DMN; Figure S1) during the first sleep session in which the FNE occurs and the second sleep session in which the FNE does not occur (Table S1). We conducted a four-way repeated-measures ANOVA on SWA with the factors being network, hemisphere (left versus right), sleep stage (slow-wave sleep versus stage 2 sleep), and sleep session (day 1 versus day 2). A factor of sleep stage was included because the strength of SWA, or sleep depth, should be different between sleep stages. If regional interhemispheric asymmetry of SWA occurs with the FNE in a certain network, this should manifest as an interaction among the factors. We indeed found the four-way interaction significant (F3,30 = 4.45, p = 0.011; Figure S1 and Table S2). The hemi- sphere 3 sleep session interaction was significant only in the DMN among the four networks during slow-wave sleep (F1,10 = 10.03, p = 0.010; Table S2). Further analyses (Table S2) indicated that SWA in the left DMN on day 1 was signifi- cantly smaller than SWA in the right DMN on day 1 (Figure 1A; t10 = 2.59, p = 0.027, d = 0.8) and was also significantly smaller than SWA in the left DMN on day 2 (t10 = 2.69, p = 0.023, d = 0.8). There was no significant difference between days in the right DMN (t10 = 0.97, p = 0.355, nonsignificant [n.s.]). SWA associated with K complexes did not show any hemi- spheric asymmetry (Figure S2).


1190 Current Biology 26, 1190–1194, May 9, 2016 a 2016 Elsevier Ltd.

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Figure 1. SWA Asymmetry in the DMN dur- ing Slow-Wave Sleep in Association with the FNE
(A) SWA in the DMN during slow-wave sleep. The red bars show the left hemisphere, and the blue bars show the right hemisphere. The values are mean ± SEM. Asterisks indicate a significant dif- ference in the post hoc tests after the four-way repeated-measures ANOVA (*p < 0.05).

(B and C) Scatter plots for the asymmetry index of DMN SWA against the sleep-onset latency for day 1 (r = 0.68, p = 0.022) (B) and day 2 (r = 0.03,

p = 0.935, n.s.) (C). *p < 0.05. The correlation coefficient on day 1 was significantly different from day 2 (zpf10 = 1.99, p = 0.046).
See Figure S1 for SWA in other networks, details of ANOVA results, and details of the asymmetry index. See also Figure S2 for additional data on SWA.


We further examined the relationship between the degree of interhemispheric asymmetry of SWA in the DMN and the degree of the FNE. We obtained an asymmetry index for SWA strength ([left SWA  right SWA]/[left SWA + right SWA]) for the DMN dur- ing slow-wave sleep (Figure S1). If SWA asymmetry for the DMN is associated with the reduced sleep quality in the first sleep ses- sion, the asymmetry index should be significantly correlated with the sleep-onset latency, which is a sensitive parameter for the presence of the FNE [3, 14]. A strong and significant negative correlation between these measures was found on day 1, but not on day 2 (Figures 1B and 1C). The correlations were signifi- cantly different between days.

To our best knowledge, regional asymmetric SWA associated with the FNE has never been reported in humans. Why was this not found in previous studies? First, visual inspection of PSG did not detect any hemispheric asymmetry in the apparent ampli- tude of SWA in the current data. Second, frequency analyses on sensor-space MEG failed to reveal regional hemispheric asymmetry of SWA (Figure S2). It may be difficult to detect the regional asymmetric SWA in a specific network such as the DMN in association with the FNE, unless sleeping brain activities are examined across different sleep sessions, hemispheres, and brain networks with high spatial resolution.

Is the regionally lighter sleep in the left hemisphere shown in the results of experiment 1 on day 1 related to higher vigi- lance to external signals? In experiment 2, we addressed this question using an oddball paradigm, where the amplitude of the brain response evoked by rare stimuli correlates with vigi- lance [15, 16] with a new group of subjects (see Supplemental Experimental Procedures). If one hemisphere is more vigilant than the other on day 1, the amplitude of the brain response should be larger in the hemisphere than in the other hemisphere on day 1. Both infrequent deviant and frequent standard beeps were presented every 1 s monaurally while subjects were asleep.

We conducted a three-way repeated-measures ANOVA on the mean amplitude of evoked brain responses with the factors of sound type, hemisphere, and sleep session during slow-wave sleep (Figure S3) in which regional asymmetric SWA was found in experiment 1. The results indicated that the mean amplitude of brain responses to deviant sounds was significantly augmented in the left hemisphere compared to the right on day 1 (Figure 2A; t12 =2.92,p=0.013,d=0.9),butnotonday2(t12 =1.37,p= 0.195, n.s.). The amplitude of the brain response to the deviant sounds in the left hemisphere was significantly reduced on day 2 (t12 = 3.18, p = 0.008, d = 1.0), while there was no significant

difference between days in the right hemisphere (t12 = 0.66, p = 0.523, n.s.). No significant difference was found in the brain responses to the standard sound between the hemispheres or be- tween sleep sessions (Figure 2B). Thus, hemispheric asymmetry in the brain responses was specific to the deviant sounds on day 1. These results indicate that the left hemisphere was more vigilant than the right when the FNE occurred. Hemispheric asym- metry in the brain responses to the deviant sounds was not found during wakefulness or stage 2 sleep (Figure S3).

Next, we found that enhanced vigilance in the left hemisphere resulted in more arousals. An arousal is defined as an abrupt and short shift of electroencephalogram (EEG) frequency [17]. We counted how often arousals occurred per minute following a deviant sound during slow-wave sleep. Arousals occurred more frequently on day 1 than day 2 (Figure 3A). Given that an arousal was induced by a monaural deviant sound, we examined whether the arousal occurrence depended on the contralateral hemisphere to the ear to which the deviant sound was presented. Here, a trial in which a deviant sound was presented to the right (left) ear is called a left- (right-) hemisphere trial [18]. The percentage of arousal occurrence following the left-hemisphere trials occupied more than 80% of the total arousals on day 1 and was significantly larger than chance (Figure 3B; Wilcoxon signed-rank test, z12 = 3.22, p = 0.001). The percentage of arousal occurrence following the left-hemisphere trials was significantly larger on day 1 than on day 2 (Figure 3B; z12 = 2.49, p = 0.013). However, this left-hemi- sphere dominance in the arousal occurrence vanished on day 2 (z12 = 0.32, p = 0.751, n.s.). These results indicate that the left hemisphere showed more arousals with deviant external stimuli than the right hemisphere during sleep on day 1 when the FNE occurred.

Does the vigilant hemisphere on day 1 produce faster behav- ioral responses to deviant external stimuli than on day 2? If the FNE plays a role as a protective mechanism such as a night watch rather than showing a merely disrupted sleep, a faster behavioral response should be generated from sleep upon the detection of deviant external stimuli in the first sleep session. In experiment 3, we asked a new group of subjects to lightly tap fingers when they heard sounds while they were sleeping, using an oddball paradigm similar to experiment 2. First, a larger number of subjects were woken by left-hemisphere trials than right-hemisphere trials on day 1 compared to day 2 (Figure 4A). Second, the reaction time from a deviant sound to tap was signif- icantly faster on day 1 than day 2 (Figure 4B). Third, this faster response on day 1 was mainly driven by the shorter time from

Current Biology 26, 1190–1194, May 9, 2016 1191

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