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| 5/24 |
| 2005/6/4-6 [Computer/HW/IO] UID:37970 Activity:moderate |
6/3 Tactiva, a new input device. Check out the videos:
http://tactiva.com/demo.html
\_ Looks nice, but I would think your hands would get tired like
that.
\_ It looks like an improvement but still not what I'm looking for.
I would really prefer an input method where I could use most of my
upper body for CAD work. The thing Tom Cruise used in "Minority
Report" is more the direction I would like to see. -- ulysses
\_ Ya, like modern mice don't tire you out. It's not a replacement
for a keyboard. It's a replacement for a mouse, the most stupid
RSI inducing input device ever made.
\_ There's no proof that computer usage through standard
I/O devices causes RSI. People with real RSI are individuals
who have to deal with heavy manual labor like meat packers
or jackhammer operators.
or jackhammer operators. -williamc
\_ You're an idiot.
\_ Seconded
\_ No, you're the idiot.
http://www.hal-pc.org/journal/01repet.html
There are no known conclusive studies linking
computer usage to either RSI or CTS. Most likely
the computer usage was at best a trigger.
Other studies have shown that the percentage of
people who develop any sort of RSI who are regular
computer operators was no different than the
percentage of people who develop it in the
general populace period, indicating that whatver
it is, it's not the computer IO that's causing it
it is, it's not the computer IO that's causing it -williamc
-williamc
\_ Hmm. My sister had RSI in her wrists; she ended up
seeing a doctor, and then eventually an ergo
consultant, and her injuries healed. And, uhm,
no, my 5' 1" sister doesn't operate a jackhammer
or any other heavy equipment, and she doesn't pack
meat. She works at a computer all day as a
statistician for UCSF. -mice
\_ I've had it. It was directly caused by using an old
and sticky Sun Type 3 keyboard in a cold room at a
shitty desk with bad posture for too long hours at
a time. I had a mild case of CTS, and it HURT.
I changed all of the above and it went away. Sorry,
no jackhammers involved. -John
\_ Wow, I guess the tendinitis in my arms was just my
imagination! Thanks crazy motd tinfoil-hat guy!
-emarkp
\_ Have you considered that it might have been the
keyboard, not the mouse, that did it?
\_ What does that have to do with anything? The
thread is "computer usage"--not keyboard vs.
mouse. -emarkp
\_ Not that I am disputing your point, but you cannot
conclude anything causal from percentages alone.
RSI can have equal probability of occurence in
general population and computer users, and computer
use could still cause RSI. In fact, can any people
who are knowledgeable about courtroom arguments
enlighten me on how lawyers attempt to prove
causation in courts? If it's a long discussion,
please email me. -- ilyas
please email me. -- ilyas (continuing incoherence
about science on the motd since 1998!)
\_ 1998? fricken noob! -meyers (since 1992)
\_ The 115 pound female I knew who had to get surgery
for carpal tunnel must have been moonlighting as
a meat packer/jackhammer operator. And she worked
long hours on not ergonomic computer systems, but
that may just be a coincidence, she's obviously
lying about the heavy manual labor side jobs she
must have been employed in!
\_ I find it somewhat amusing that all we have is
anecdotal evidence. As I stated before, there
are no conclusive epi studies that support
CTS with the workplace in general, although
there appear to be strong causal linkages to
heavy manual labor.
Here's another link:
http://ocsonline.net/carpal_tunnel_syndrome.htm
I'm highly skeptical that CTS is caused by
computer IO. If it was you'd actually see a
direct statistical correlation to computer
usage and CTS or other ailments of the sort.
\_ To repeat myself again, no you wouldn't,
necessarily. For example, it may be that
people who are predisposed to computer use
also have a natural resistance to developing
CTS. You don't know what you are talking
about. -- ilyas
\_ However, it probably *is* that people
who are predisposed to computer use have
a natural predisposition to CTS. :)
To echo your statement (I think):
It may also be that computer use causes
it at the same rate it is caused in the
general populous by other mutually exclusive
factors. (thus no correlation but STILL
causation as you say below). Still though
I think the broader point of the op is that
typing doesn't cause it any more than
doing whatever else people are likely to
have to do to get by, which a lack of
correlation certainly is evidence of.
\_ No. You are not paying attention! You
cannot conclude ANYTHING causal from
correlative information alone, regardless
of what that information might be. It
may be that the frequencies are the same
for computer users, typers, and the
general populace, yet computer use causes
CTS, and typing does not. In order to
determine anything here you need to either
force people to use typewriters or
computers (which decouples the hidden
common causes involved), or use randomized
experiments (which fakes the same kind of
decoupling). -- ilyas
\_ speaking of paying attention: Who said
anything about concluding anything?
Certainly not me. There are all kinds
of evidence. Even anectdotes are
"evidence" after a fashion. The
evidence may not point in the right
direction and it certainly is not
conclusive, but a demonstrated lack of
correlation between typing for a
living and CTS and increased risk of
CTS certainly *IS* evidence that
typing doesn't cause CTS anymore than
average. Especially in the absense of
any reasonable hypothosis about why
people in that field would be unrepre-
sentative and Especially since i'd
predict that people in that field, if
anything, should be more likely to get
it and more likely to whine about it
when they did.
\_ The original quote was: 'same
frequencies indicates computer use
does not cause CTS.' This statement
is false. That's all I am trying
to say. You can resume begging off
on technicalities now. -- ilyas
As it stands now, we don't really know what
causes CTS, and at best we can only guess.
People who do have CTS may have gotten it
regardless of computer IO or not. Think about it,
the current generation of workers are involved
with the least amount of manual labor in probably
the history of mankind. Why then did our
forebearers not complain constantly about CTS?
Why is it a "modern" phenomenon? If you don't think
working on a farm during the turn of the 20th
century required constant repetitive tasks,
well, what can one say...
Also, one would think CTS would be much more
prevalent in the past before the advent of
modern soft-touch keyboards. Manual typewriters
are much harder on the hands. In addition,
writing in general is much harder on the hands.
I get writer's cramp, I've never gotten "typist"
cramp, especially on a modern day computer
keyboard. Admittedly, some of these keyboards
are horrid to type on, and no doubt they would
lead at least hand fatigue if used in the long
term, but realistically, I think human beings
are better designed in general to withstand
impact than what comes out of typing on a typical
modern day keyboard, even if you are typing at
100 WPM for an extended period of time. Also,
the average programmer probably types a lot
less than a legal secretary, and it's been
stated a number of times that there is no
correlation between developing CTS or IRS and
the amount you type, which makes one wonder...
Whatever the cause is, it's not computer IO.
\_ williamc, I used to have an "emacs pinky." That is, after
using emacs for over 10 years I started having pains in my
left pinky. The pain spread to my whole arm and I had to
get physical therapy a few times. But the thing that really
helped was using a Kinesis keyboard in which I have to use my
thumb to press CTRL and ALT keys. From what you're saying,
is there no difference between the quality of IO, one that
requires more effort or more frequency on certain fingers? |
| 5/24 |
|
| tactiva.com/demo.html Introduction to the TactaPad Movie This movie is a silent screen capture of a user interacting briefly with a few applications on Mac OS X It demonstrates how the TactaPad is full y compatible with existing software. Advanced Interactions in TactaDraw 3:57 See how the features of the TactaPad can improve the user interface for a drawing tool. This movie demonstrates different interaction techniques which use both hands, either working together on one task, or in paralle l on two related tasks. It also shows how tactile feedback can be used t o augment the user experience. |
| www.hal-pc.org/journal/01repet.html by Brooke E Smith The Bogus Epidemic Everybody knows that using a computer keyboard can cause repetitive stres s injuries. After all, we're being bombarded with stories in the popular press about the number of employees who have become disabled from keybo ard work. We're constantly being told how to prevent "ergonomic" ills th rough use of special chairs, keyboards, and other devices. And if it's t oo late for prevention, billboards for hand surgeons offer quickie cures for carpal tunnel syndrome and other so-called cumulative trauma disord ers. However, before you pay off the next workman's compensation claim by a co mputer operator, or purchase a wrist rest for your own use while keyboar ding, consider that scientific evidence linking computers with carpal tu nnel syndrome or any other medical condition is strangely lacking. When doctors, ergonomists, attorneys, or anyone else are asked to provide rel iable scientific evidence that these conditions are actually caused by c omputer use, they fail to do so. For this reason, every single lawsuit b rought by a computer operator claiming damages based on keyboard use tha t has gone to trial has ended up in a judgment for the defense. Moreover , cities such as Miami who have required their employees to prove that t heir injuries were caused by computer use in order to get workman's comp ensation payments have avoided paying out any taxpayer dollars on these claims. Absent the hype by plaintiff's lawyers, chiropractors, inventors of ergon omic devices, and others profiting from the repetitive stress injury epi demic, the essential facts about these conditions are as follows: 1 What is a "cumulative trauma disorder" or "repetitive stress injury"? Neither "cumulative trauma disorder" ("CTD") nor "repetitive stress injur y" ("RSI") is a specific medical condition. Some limit use of the term " CTD" to conditions arising from obvious trauma or injury that occurs mor e than once, such as might be experienced by someone who sustained multi ple but separate injuries to his back from playing football on different occasions over the years. In contrast, the term "RSI" is often applied to repetitive activity which is not inherently harmful or injurious, but which is alleged to become so due to the sheer number of repetitions or the presence of other circumstances which "stress" the body. In the context of keyboard use, the terms CTD and RSI have often been app lied to a wide range of different medical conditions, including tendinit is, De Quervain's syndrome, trigger finger, epicondylitis, muscle fatigu e and bursitis, as well as carpal tunnel syndrome ("CTS"). Not only are each of these a separately diagnosable condition with specific and diffe rent causes and treatments, but each affects a different part of the hum an body; for example, trigger finger concerns individual fingers, while epicondylitis ("tennis elbow") is associated with pain in a completely u nrelated joint. By dealing with these separate medical conditions under the umbrella of " CTD" or "RSI", proponents of the epidemic blur the distinctions necessar y to understand what scientific evidence exists regarding computer use a nd the alleged causation of these medical problems. For example, they ca n't show you a study linking computer use to development of epicondyliti s; They can't explain why operating the same system would cause one person to have problems with her fingers, while affecti ng another's back or shoulder instead. And they completely avoid the cri tical question: why the vast majority of people experience no problems w hatsoever from their computer work. By referring to a whole family of unrelated conditions rather than focusi ng on specific medical problems, users of the terms "CTD" and "RSI" can conveniently extrapolate from one condition to another. Anecdotal inform ation linking a long day of computer use with muscle fatigue thus inappr opriately becomes "proof" that keyboarding also "causes" CTS. Soon every thing becomes associated with everything else, though not by any logical or scientifically rigorous means. Most of the publicity has focused on CTS, which is an upper extremity dis order resulting from compression of the median nerve within the carpal t unnel, or wrist area of the hand. A person is only properly diagnosed as having CTS when symptoms such as tingling, numbness, swelling, lack of grip strength, or pain are present in the hand, and when a nerve conduct ion study confirms that the median nerve is reacting abnormally slowly. The nerve conduction test is essential, because many people may have the symptoms of CTS while having normal nerve conduction. However, medical p roviders do not uniformly require their patients to have nerve conductio n studies performed before making a diagnosis of CTS. Therefore, statist ics regarding the incidence of CTS in the general population are likely skewed in favor of overdiagnosis of the condition. For there to be a causal link between typing on a computer keyboard and d eveloping CTS, the median nerve would have to be compressed as a direct result of that specific activity. However, internationally-known hand su rgeon Peter A Nathan of Portland, Oregon, who has conducted many studie s analyzing the hand-activity components in a wide variety of job catego ries, has been unable to identify any job-related activity (including ke yboarding) which produces biomechanical forces sufficient to compress th e median nerve at the wrist. While some medical experts speculate that the median nerve may be compres sed when pressure in the carpal tunnel rises, and that typing with a ben t wrist may cause a temporary rise in carpal tunnel pressure, no one has been able to provide reliable scientific evidence linking a temporary r ise in pressure to development of CTS. Nathan and others support the opposite conclusion: the activity of keybo ard use is not associated with the development of carpal tunnel syndrome . But even if there is no valid scientific study linking computer use with CTS, what about the other so-called CTDs such as tendinitis? Surely if a good word processor strikes keys thousands of times, day after day, it stands to reason that the sheer number of repetitions could cause injury . Not true, according to Nortin M Hadler, MD, Professor of Medicine and Microbiology/Immunology at the University of North Carolina School of Me dicine. Hadler has determined that repetitive motion is not hazardou s to a person performing a task when the elements of the task are themse lves customary and comfortable, and the number of repetitions are not pa tently unreasonable. Hadler conclu des that there is no valid scientific basis for finding that CTDs are ca used by such reasonable repetitive motion. Nathan indicates that keyboard use and repetition in general prot ect against the development of CTS. As mentioned above, there is considerable doubt as to the number of actua l CTS cases among those being diagnosed as such. There is also a lack of valid epidemiological studies regarding the incidence of CTS in the non -working (or non-computer-using) population. As a result, there is no wa y to accurately determine whether there is an epidemic present. Although there is a paucity of scientific evidence linking computer use t o CTS, a number of studies have been performed associating this disease with various personal factors. The probability that a person will be dia gnosed as having CTS increases if the person is female; Personal habits such as use of tobacco, alcohol and caffeine and failure to exercise regularly also raises the likelihood that a person will develop CTS. Also, psychosocia l factors which determine whether a person is undergoing stress at work or at home, such as employer/employee relationships, work changes, and o ther elements which may affect someone's overall satisfaction with life are also thought to play an important part in separating those who devel op CTS from those who don't. Finally, a number of medical providers beli eve that a large number of cases of CTS have no discernible cause. It is possible that even if working on a computer does not cause CTS or a ny o... |
| ocsonline.net/carpal_tunnel_syndrome.htm Carpal Tunnel Syndrome Work related incidence of Carpal Tunnel Syndrome (CTS) is likely to be a synergy of genetics and physiology along with lifestyle factors in addit ion to biomechanics. Carpal Tunnel Syndrome affects motor and sensory functions of the median nerve from the carpal tunnel (wrist) into the hand. It is the most commo n nerve entrapment of the upper extremity. ANATOMIC CONSIDERATIONS The floor of the carpal tunnel (CT) is the carpal bones. These structures create a stiff passageway for its tightly packed contents. The median nerves takes up more than 50 % of the tunnel. Increases in the volume of the contents and/or dimension changes in the t unnel are important to the cause of CTS. PHYSIOLOGIC CONSIDERATIONS The above mentioned pressure increases/decreases dimensions of the CT pro duces, especially over time that in turn negatively impacts the microvas cular system of the epi, peri and endoneurium of the median nerve. An ac ute episode, a series of acute episodes or sustained pressure contribute to chronic CTS. PHYSIOLOGIC RESPONSES AND CLINICAL SYMPTOMS Symptoms: numbness, paresthesia, sensory changes and weakness of the thenar muscles. They include an adductor, an abductor thenar and the hypothenar. Tissue Responses: epineurial edema, scarring and impairment o f intraneural circulation and Intrafascial edema Structural Changes: distended internodes and myelin derangeme nt DIAGNOSIS Structural AND functional changes in the median nerve are crucial to a diagnosis of CTS EMG studies to access and quantify conduction velocity are considered to be a gold standard for diagnosis. Impaired medial nerve velocity acro ss the carpal tunnel does not necessarily imply CTS. An 11 year study of sensory median nerve velocity clinical symptoms and c onfirmed CTS was done on 289 industrial workers. Diagnosis was based on EMG of median nerve velocity with simultaneous specific symptom complex. STATISTICS 1984 942 hands 471 workers 1989 630 hands 316 workers 1994-95 578 hands 289 workers In 1984 41 hands were confirmed CTS. The number of unconfirmed median nerve slowing did not parallel to the nu mber of confirmed CTS. PROBLEMS with EMG Interpretation 1) Testing that does not adjust for: Age, gender, body mass index, wrist geometry, electrode placement, bod y anthropometrics, hand temperature. Here they are: Pregnancy, hypothyroidism, diabetes, gout, rheumatoid arthrit is, familial CTS, long term dialysis, previous hand and/or wrist injury, hypertrophy of the lumbrical muscles, obesity, physical inactivity, low physical fitness. OCCUPATIONAL EPIDEMIOLOGICAL CONSIDERATIONS Epidemiological evidence of the work relatedness of CTS has been extensiv ely debated. The NIOSH states that evidence is clear that exposure to a combination of job factors studied increase the risk of CTS. Strong is defined as reflecting a very likely causal relationship between intense and/or long duration exposure to a combination of risk factors. Generalized, quantitative and validated def initions of intense or long term are quite difficult to acquire. Chiang at al studied more than 200 workers in a frozen food plant and it found that that repetitiveness with cold temperatures did correlate with CTS In more than 30 studies reviewed used statistical designs that have limit ed ability to address causality. For example cross-sectional designs are not able to provide evidence of a relationship between exposure and eff ect. Another 5-year study found that median nerve velocity slowing could not b e correlated with occupational hand use. In fact slowing was more relate d to age and hand dominance than occupational hand use. It would be simple if specific sets of risk factors could be definitely r elated to occupational CTS; not to say that there is not a general relat ionship between exposure to biomechanical and environmental (cold temper atures) risk factors in the development job related CTS. There is a sub stantial body of evidence between biomechanical risk factors and CTS but unambiguous evidence is not compelling. It is hoped that the above inf ormation will be useful in sorting out the complex issues of CTS diagnos is solely from EMG evidence of median nerve velocity slowing and correla ting a diagnosis of CTS to occupational hand use. |