Comment by seanhunter | Hacker News Reader

Comment by seanhunter | Hacker News Reader

Fun (unrelated) oscilloscope story happened to me recently. I was having some problems with fingers of my hand going numb so the orthopedic surgeon sent me for a procedure she said would be "unfortunately pretty unpleasant" called a "nerve conduction study" with an eminent London professor to try to diagnose the problem.

When the day came the dude showed up with a laptop attached to a small box and a number of leads. I said to him[1] "hey there, I'm an engineer, would you mind telling me how this study works" and he (delighted) explained to me that although his title was a professor of neurology he was actually a biomedical engineer and the procedure was hooking me up to an oscilloscope and sending currents down the various nerves of my arm to see whether (or not) they were detectable on the oscilloscope and therefore being conducted properly down the nerves. So I spent 30mins or so having various electric shocks applied to my arm and looking at the pictures on the (very fancy) oscilloscope while shooting the breeze about medical imaging and machine learning with this professor.

The procedure was mildly unpleasant but super-interesting as a result.

[1] Sort of as a coping strategy because I expected it to be painful.

The biomedical equivalent of poking you with a multimeter conductivity tester that goes "beep".

I really hope someone had a sense of humor and made that oscilloscope beep on detecting a connection.

You joke but there's a whole branch of fake science built on this: https://quackwatch.org/related/electro/

Ah the machine that goes “ping” This is my favourite. You see, we lease this back from the company we sold it to, and that way, it comes under the monthly current budget and not the capital account.

I had a nerve conduction test on my arm, it was pretty neat! I didn't find it uncomfortable, just a bit of a tingle.

My issue was a combination of a previous shoulder injury and bad sleeping position and bad sitting at desk position (resting forearm on the edge) that would result in numbness in my hand and fingers.

I'm more conscious of how I sit and sleep now (as much as you can be "conscious" of how you sleep!) and I started indoor rock climbing which has really transformed my upper body in terms of arm, shoulder and back strength and mobility. Funny, I don't look any different, but I can hold onto and hang off things well good. :P

I had one due to a bulging disc in my neck and some pins and needles - it was fascinating, but I still remember them turning on the audio and letting me listen to my nerves trying to flex various muscles! My biceps sounded like a bit like white noise (good), while my triceps sounded like a plastic bag flapping outside a car window (bad!) The way they explained it some subset of my tricep nerves were firing harder to try and compensate for the ones affected by the disc bulge - but they couldn’t keep up the firing rate by themselves. Really interesting and somewhat explained my mediocre push-up performance!

Similar story here. I used to have neck pain and shoulder frequently. About 2 years into bouldering, all of them are gone. And I have yet to face a jar I couldn't open

This sounds like Electromyography (EMG). A pretty common technique in Neurology to diagnose problems in nerves and muscles.

https://en.m.wikipedia.org/wiki/Electromyography

They are different, but often done together. EMG measures electrical activity of the muscles and their connection to the nerves, and NCS measures (unsurprisingly) the conductivity of the nerves

> nerve conduction study

Never again! I will deal with whatever life throws at me (including my tingling fingers), before I go through that again. The doctors were so scared of the way I looked when they were done (white as a sheet and listless), that they had me lie down in a side room for about an hour, before they would let me leave. That was my own private version of hell.

You mention below "almost completely resolved by physiotherapy exercises", and that is where I'm at now, thankfully. In the future, I'll exhaust this resource before ever doing more invasive studies.

Man I'm sorry to hear that experience. Glad you're doing ok on your recovery.

Is your problem resolved? Did you find the cause? I've found that when I bike long distances that no matter what the weather is I have to wear thick padded gloves so that I don't end up with numb fingers for days afterwards.

I don't think your issue is super uncommon, I experience it myself, as does most of my family. Unless all of us share an undiagnosed condition of course

vibration related?

https://en.m.wikipedia.org/wiki/Vibration_white_finger

That's interesting, I never made that link. These symptoms did appear relatively shortly after doing a lot of work with a light industrial jackhammer to remove tiles from an old bathroom. There may well be a connection. But that was a one off and since then it appears when doing > 100 km in a day or so on the bike. I thought it was circulation related, never even thought about vibration. Thank you.

Your symptoms are common in motorcycling too. The remedy is to loosen the grip, which is advised anyway for smoother and safer driving. "As if you were steering just with your index finger and thumb's tips".

Hm, why is that safer?

Forcing the front wheel "against its will" is gonna make it lose its grip or make the whole bike unstable when turning.

I hadn't thought of that, thanks. You do steer with the torso, after all.

It's the worst when you have people sitting on the back that go against the natural lean of the bike.

That I can try right away (today, even), thank you for the tip!

2nd reply, so, not enough time to do a long trip but it definitely feels that a looser grip helps but: I'm afraid that I'll lose control of the bike on a pothole and I can't afford another fall. So I'll definitely do this alternating hands and I'll still try to find good handlebar covers with padding in them (round ones, handle bars aligned with the grip so there is the most surface and least pressure).

Good to hear. I hope you can find a balance. Mostly just not "clamping" so much, which is maybe the reason for strain.

I try to not clamp and neither lean much on the handlebars. So I have to move my hips and body a bit, but I do see improvement in handling. If I hit a pothole or debris, the bike will autocorrect much better if there's less pressure on the handlebars/front wheel.

Part of this is that I'm simply afraid to fall again (I have half an Ikea's worth of steel in one leg and another fall would be very bad indeed). So some of this rigidity is probably simply due to that fear.

> But that was a one off and since then it appears when doing > 100 km in a day or so on the bike.

Unfortunately vibration-induced Raynaud's syndrome has no cure, so it may be continuing to affect you.

I also have Raynaud's which affects me when cycling or when using an outboard throttle for extended periods. Apart from hand exercises which delays onset of symptoms, there's apparently nothing to be done.

Thick gloves are ok but uncomfortable in hot weather - there are also ergonomic grips (eg from Ergon, SQLab) and gel pads that can be fitted over/under the grip tape that can be used instead. Also various ways to directly reduce handlebar vibrations (like the Cane Creek eeSilk stem).

Yes, that's precisely what I've found, it works well but not when it's hot out and this summer has been particularly nasty in that sense.

I'm looking at a pair of leather-over-foam paddings integrated with the grips themselves like I have on a tandem where I noticed I don't have that problem. But that particular model has proven hard to find.

Have you looked into a bike fit? It's quite a common problem, and setting up your bike differently could help you relieve some pressure at hot spots. For instance shortening the stem could give you a more upright position and less weight on your arms. A wider or narrower handlebar could alter the angle of your wrists (on a road bike). Etc. etc., many things to look into, depending on what the cause is.

Yes, I worked in a bike store and have access to all the right measuring tools. The fit itself isn't so much the problem as the inevitable areas where my hands contact the handlebars. My grip is too tight so that's why the padding helps as much as it does, it is much softer than the material that the handlebars are covered with. On warm days it isn't perfect though (because it also covers parts of my hands that I'd rather have exposed on warm days) and I've been looking at getting softer coverings for the handlebars to help with that. I've already changed a lot about the geometry of that particular bike to improve matters substantially, this is the one remaining bit.

Yes. We did find the cause and my problem is almost completely resolved by physiotherapy exercises. It took a few weeks to sort itself out and if I am not careful it starts coming back but it's mostly gone.

Long version in case this helps someone: I have hypermobile-type Ehlers-Danloss syndrome, which is a disorder affecting the body's connective tissue. Among other things it means I'm more bendy than I should be. As a consequence I have to be careful not to make too extreme movements because I can injure my joints. In this case, the problem was because I wasn't utilizing my full range of movement, my nerves were essentially getting stuck in various places where they travel through small gaps or over tendons or whatnot. The solution is to do (gentle) stretching-type exercises which are designed to make the tendons do their full range of movement (I have to do this carefully so as not to hyperextend and injure myself), which causes the nerve to be pulled through these gaps and unstick itself. Because this process is like floss being drawn through a gap between teeth, the exercises are actually called "flossing" by physios

Here's an example specifically in the domain of sciatica, although that's not what I do[1]

[1] https://www.medicalnewstoday.com/articles/nerve-flossing#exe...

Wow, that's quite the story. Great to see you managed to both identify and fix it in such a non-invasive manner.

I was told by a physiotherapist doing his Phd that if everybody did Tai Chi and indian Yoga he would be jobless - Tai Chi helps with "stretching" the nerves and Yoga does the same with muscles. (Your nerve flossing description was very insightful and helped me better understand the process).

Yes. I did actually do Tai Chi quite seriously some years ago and starting to do some of my old Chi Gung exercises has been very helpful in this recovery process. I have to be quite careful with yoga because of the hypermobility - because extreme stretching can cause me problems.

Some nerve flossing exercise blocks now even contain some Tai Chi movements.

second the "check Your bike fit". In my opinion, the checklist is:

1. check the bike fit (probably the main problem)

2. add some mobility / core training (at some point if You bike long distance out of the blue without much training, some bits in Your body will simply break / strain no matter how good Your bike fit is)

3. in case of problems, look up the terms "cyclist palsy" and "ulnar / median nerve flossing exercises". It should help recover a bit quicker.

All that being said, I'm typing this with a pretty severely tingling median nerves in both hands. 1200km in 86h without much training during the season and with an improperly adjusted saddle (didn't mark the position before packing the bike for transport). Yeah, do as I say, not as I do.

(1) obviously, done right after I bought the bike (and I totally understand why you wrote that, the vast bulk of the people I see riding bikes give me lower backpain just looking at them...)

(2) I do thousands of km / year on my bikes (140 just this weekend), but I do recognize that it may be too limited by itself and it's true that I don't do many other things besides biking, walking stairs and sitting all day. So some more variation might help. Thank you for the tip!

(3) Interesting, I know about the ulnar nerve and have had issues there on one hand but that was long ago and not nearly as bad as this. It also seems as though it was originally triggered by the use of a jackhammer (someone else pointed this out downthread, that vibration may be the trigger, I was focusing on pressure rather than vibration, and I never made that link before). 1200 km in 86 hours???? that is insane. Best I've ever done was 300 in 24 and that was in my prime on a really light bike (cycle around the IJsselmeer inside a day). I wouldn't even think about doing 1000+ in less than 5 days today.

Lots of good stuff in this thread, thank you all!

(1) in my case, "bike fit" is more of a process than a one time thing. I keep tweaking it a bit through the year as I train (mainly saddle fore/aft, but handlebar height / angle as well as extra wrap / gel pads sometimes)

(2) the distance alone is just part of the job. I do about 5.000km a year just on the 2x10km a day commute. That's got little to do with mobility / intensity though. And does little to posture. For me,I kinda regret now doing only a couple of 200km+/day low intensity rides this season. This would have revealed the problems much earlier...

(3) 1200km is Paris-Brest-Paris. The time limit for that one is 90h, so 86 is "barely just made it". But I went full bikepacking on this one. Took way too much gear, which slowed me down a lot in the climbs. Also, couldn't use my aerobars in the groups, which put way more stress on my wrists than I thought it would. In the end, it's the combination of vibration / limited options for hand position change / too much weight (fault of weak core muscles / posture) and the long continuous repetitive stress that does the damage.

> in my case, "bike fit" is more of a process than a one time thing

That's very apt, and likewise. I see a new bike as the beginning of a long journey to where it is all set up and tweaked to just how I want it. Also: most bikes straight from the factory are rough ideas of what you could do with it and as a rule need all kinds of tightening, especially spokes and various friction grips. Also not rare to find cables that are too long / untrimmed, electrical bits that are so loose they can get trapped, loose bolts (and even sometimes missing ones). Think of it as an almost but not quite assembled kit and you wouldn't be too far off. I also probably have about a bike's worth of spare parts in every category and more than one in some (pedals, kickstands, saddle pins, pinions, handle bars etc).

> the distance alone is just part of the job. I do about 5.000km a year just on the 2x10km a day commute.

That's still quite a bit of good training. A family member does 2x30 km 6 days per week, 48 weeks / year. He should probably do bike reviews :)

> For me,I kinda regret now doing only a couple of 200km+/day low intensity rides this season. This would have revealed the problems much earlier...

I do a 2x70 once, sometimes twice weekly and on that distance most issues will show. I also can't do much longer anyway without breaking it up (knee issue, lots of steel in one leg). It's one reason my e-bike sees more work these days than the regular one.

> 1200km is Paris-Brest-Paris. The time limit for that one is 90h, so 86 is "barely just made it".

To me that is far out of reach, consider me seriously impressed with this.

> But I went full bikepacking on this one.

Even more impressed!

> Took way too much gear, which slowed me down a lot in the climbs.

Yes, weight is killing. We have a tandem here and I take my sons on rides with it and uphill you might as well be walking (which we sometimes do).

I don't like riding in groups at all, these are all solo rides or with one child.

Check Francis Cade's youtube channel: 'bike fit james' is a less regular guest, than previously but his advice will assist you in ignoring the bullshit bike sellers, and manufacturers er....saddle us with. Nb I regularly do 100km+. Many 100 milers and quite a few 200+ without problems. Saddle height and cleat position (I also went to mtb cleats on my roady) seem to be major culprits. Ymmv, but it's a good place to start.

Cade's bike fit is generally OK, but IMO he's lately been way too click-baity with the videos and trying to tailor his texts to the youtube algorithm ("10 things ...", etc.). Maybe it's just me, but I find it somewhat annoying to sift through.

Probably wouldn't hurt to second-check these days.

My $.02 : Cam Nichols for bike fit tips (and a wonderful aussie accent :-) and Dylan Johnson for science checks and backwards cap comments ;-)

I had the same experience for the same symptoms. The long and short of it was that I should stop leaning on my elbows on the desk, because that can damage the nerves that run across your elbow. Made a conscious effort to avoid doing that for a while and the damage fixes itself.

I hope you have the same problem I did, was an easy fix.

Histidine helps remyelinate the nervous system. If holes appear in the myelin sheath electrical signals wont get past the holes.

Lack of B6 can cause peripheral neuropathy which has symptoms like you describe. Can be linked to diabetes, some metals and B6 deficiency.

Conversely, in supplementing individuals, there's also B6 toxicity which has generally the same symptoms.

I've run into this when doing a more complex stack and neglecting to check the level of the B6 in the various sources.

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