Study Protocol for CTS and Keyboard Controlled Randomized Trial
Condition: Carpal Tunnel Syndrome
MeSH terms: Carpal Tunnel Syndrome; Syndrome
Study type: Interventional

Summary: 
      The study hypothesis is that there is a relationship between the keyboard layout and carpal
      tunnel syndrome (CTS). Specifically, use of the standard QWERTY keyboard increases the risk
      of symptoms of carpal tunnel syndrome. The QWERTY keyboard requires more effort by the
      fingers than necessary to perform the required work, i.e. data or word entry; up to 200
      percent more flexion and extension and 100 percent more distance traveled.

      The purpose of the protocol is to evaluate two keyboard layouts for carpal tunnel syndrome
      therapy, and to see if the efficient keyboard, Finger Relief, can be used as an adjunctive
      tool to other treatments or therapy for CTS for typists. Subjects who had received a
      diagnosis of carpal tunnel syndrome from their medical doctor and, where not contraindicated,
      had received confirmation of the diagnosis of carpal tunnel syndrome with a nerve conduction
      velocity (NCV) study participated in four typing sessions to compare onset and severity of
      carpal tunnel symptoms. Testing sessions alternated between keyboards. The keyboard selected
      for the first typing session was determined by random assignment. Twenty subjects completed
      all four typing sessions. The test protocol consisted of a medical history, 3 tests of the
      subjective pain experience of the subject (visual analogue scale / verbal rating scale, and
      hand diagram), 2 clinical measures of physical manifestations of swelling associated with
      carpal tunnel syndrome (water volume/tape measure), and a measure of the length of time spent
      typing on each keyboard layout - QWERTY and TheOrdinals (the Finger Relief keyboard).
    

Detailed description: 
      The current study is the first clinical study of a keyboard with patients diagnosed with
      carpal tunnel syndrome. Previous research has compared the angular motion of the fingers in a
      comparison of QWERTY, Dvorak and Finger Relief keyboards (Robertson et al., 1995). However,
      in these studies the subjects had no diagnosis of carpal tunnel syndrome.

      The typing test used typical English word combinations of letters which could be easily
      repeated for any layout. On the QWERTY keyboard, pressing the D and E flexes the middle
      finger. TheOrdinals letters (A D E H I L N O R S T) on QWERTY has 6 flexions, 1 each for the
      left middle; right middle, right ring, right index, 2 each left index fingers. TheOrdinals on
      Finger Relief keyboard have no flexions or extensions of the fingers The keystrokes were
      noted. The goal was to type to pain, change in feeling, numbness or tingling. The beginning
      and ending time was recorded manually with reference to a wristwatch or clock. Each of the
      four typing sessions ranged from 20 minutes (very little typing occurred) to more than an
      hour (extensive typing occurred without a report of symptoms). Pretyping measurement
      activities took about 10 minutes, including completing the analogue scaled self reporting
      test and water displacement test. Following this pretyping data collection, the subject was
      instructed to type until a change in pain was noticed. Post-typing measurement activities,
      including water displacement, a check for swelling, and self-report measures also took about
      10 minutes.

      The subject was then scheduled to return to the clinic no sooner than until an overnight had
      passed, or after any swelling has gone down. The protocol was repeated on a similar keyboard
      with only the letters rearranged. On the Finger Relief keyboard, pressing the D and E
      requires minimal flexion, as pressing the middle and index finger on the home row
      communicates the letters.

      The study population was those who had been diagnosed with carpal tunnel syndrome. The FDA
      asked that the reference group consist of 20 individuals (no restrictions for the number of
      men and women). There were no minimum or maximum requirements of age, subjects were only
      required to have a history of carpal tunnel syndrome or similar problems when performing
      typing activities prior to study enrollment. Each subject confirmed a history of carpal
      tunnel syndrome, presumably causing difficulties in performing typing activities. However
      typing problems were not required for participation.

      A total of 64 subjects responded to the study advertisements. Thirty-three of these subjects
      did not enter the study. Many were missing either the NCVS or a diagnosis of carpal tunnel
      syndrome from a doctor (14). Several did not respond to attempts to schedule study sessions
      (8). A few moved away from the area prior to study participation (4) or were too ill to
      participate (2). The remainder had insufficient interest to commit to participate in four
      testing sessions (3); were looking for treatment options, rather than a CTS study (1); or
      were advised by an attorney to decline participation in a CTS study, pending litigation that
      the subject was pursuing (1).

      Thirty-one subjects completed the all steps before beginning the typing exercises, which
      included a medical history, informed consent, CTS diagnosis, and NCVS confirming the CTS
      diagnosis. Eleven withdrew or left the testing incomplete. Ten of the eleven dropouts were
      employed at office work, the other was employed as a registered nurse. Five withdrew prior to
      initiating study sessions. Six withdrew after beginning a study session but before completing
      the remaining sessions and did not respond to efforts to schedule the remaining tests. Four
      dropouts started with the QWERTY layout. Two started with Finger Relief. Four dropouts
      completed only one study session (three started with QWERTY, one began with Finger Relief).
      Two dropouts completed two study sessions (one began with QWERTY, one started with Finger
      Relief). Twenty subjects completed all 4 study sessions and are included in the analyses
      described in later sections of this application.

      Swelling is a hallmark of CTS, because the median nerve must be compressed. Prior to this
      study, it was unknown whether swelling could be externally measurable in the least severe
      cases. Although the literature suggests that there is some swelling in all stages (1, 2 or 3)
      of CTS cases, the literature did not designate swelling by stage. Classic inflammation is
      measured by fever (rise in temperature), color (redness), swelling and pain. Only swelling
      and pain are externally measurable, without invasive procedures. The pre typing hand and
      wrist volume were the base line from which swelling was measured. Assuming typing causes
      measurable swelling, before the subsequent typing sessions, a sufficient time had to have
      passed for the swelling to return to base line. Thus, base line was defined as a return of
      external parameters (pain and swelling) to that which was measured before the first typing
      test session.

      Swelling was measured by comparing the increase in hand volume before and after the activity
      as measured by the water displacement method. Water displacement was measured to determine if
      an increased amount of water from the hand and wrist measurement was displaced after typing
      on QWERTY keyboard as compared with typing on the TheOrdinals (the Finger Relief keyboard)
      keyboard. It was hypothesized that there would be a significant relationship between the
      increased amount of water and the use of the QWERTY keyboard.

      The data were analyzed using a personal computer and statistical software. Calculations
      between the differences of means of swelling and pain, between the QWERTY and TheOrdinals
      (the Finger Relief keyboard) keyboards were completed. Regression techniques were used to
      estimate the differential impact of typing with each keyboard on swelling and pain. Means
      differences and regression techniques were also used to examine the effect of keyboard type
      on duration of typing.
    

Intervention name(s): Interossei Lumbricals Neuro Interface; Standard QWERTY keyboard
Intervention type(s): Device; Device
Intervention description(s): Finger Relief's keyboard home row layout [actual home row placement order: asdeihotlrn], plus substitutions on the upper row [qwfgjyuk;p] and bottom row [zxcvb'm,.] moves or shifts finger and thumb movement from the elbow muscles to the finger muscles. The movement of finger bending toward the palm is shifted to the interosseous and lumbrical muscles of the hand and fingers from the full flexion and extension muscle control to reduce contraction and expansion of tendons and the movement in the carpal canal adjacent to the median nerve and reduces pressure on the median nerve. Pressure on the median nerve compromises the nerve leading to symptoms of the carpal tunnel syndrome of pain, tingling, and numbness.; Report of onset and severity symptoms of carpal tunnel syndrome when typing with QWERTY keyboard and the Finger Relief device.
Other intervention name(s): Finger Relief; Interossei Lumbricals Neuromuscular Technology Interface
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: carpal tunnel syndrome; repetitive stress disorder