Low Keyboard Research Articles

Does computer use affect the incidence of distal arm pain? A one-year prospective study using objective measures of computer use

ObjectivesTo study how objectively recorded mouse and keyboard activity affects distal arm pain among computer workers.MethodsComputer activities were recorded among 2146 computer workers. For 52 weeks mouse and keyboard time,...

Does computer use affect the incidence of distal arm pain? A one-year prospective study using objective measures of computer use

To study how objectively recorded mouse and keyboard activity affects distal arm pain among computer workers. Computer activities were recorded among 2,146 computer workers. For 52 weeks mouse and keyboard time, sustained activity, speed and micropauses were recorded with a software program installed on the participants' computers. Participants reported weekly pain scores via the software program for elbow, forearm and wrist/hand as well as in a questionnaire at baseline and 1-year follow up. Associations between pain development and computer work were examined for three pain outcomes: acute, prolonged and chronic pain. Mouse time, even at low levels, was associated with acute pain in a similar way for all the examined regions. There were no exposure-response threshold patterns. Keyboard time had no effect. Mouse and keyboard sustained activity, speed and micropauses were not risk factors for acute pain, nor did they modify the effects of mouse or keyboard time. Computer usage parameters were not associated with prolonged or chronic pain. A major limitation of the study was low keyboard times. Computer work was not related to the development of prolonged or chronic pain. Mouse time was associated with acute distal arm pain, but the impact was quite small.

The effects of split keyboard geometry on upper body postures

Split, gabled keyboard designs can prevent or improve upper extremity pain among computer users; the mechanism appears to involve the reduction of awkward wrist and forearm postures. This study evaluated the effects of changes in opening angle, slope and height (independent variables) of a gabled (14°) keyboard on typing performance and upper extremity postures. Twenty-four experienced touch typists typed on seven keyboard conditions while typing speed and right and left wrist extension, ulnar deviation, forearm pronation and elbow position were measured using a motion tracking system. The lower keyboard height led to a lower elbow height (i.e. less shoulder elevation) and less wrist ulnar deviation and forearm pronation. Keyboard slope and opening angle had mixed effects on wrist extension and ulnar deviation, forearm pronation and elbow height and separation. The findings suggest that in order to optimise wrist, forearm and upper arm postures on a split, gabled keyboard, the keyboard should be set to the lowest height of the two heights tested. Keyboard slopes in the mid-range of those tested, 0° to −4°, provided the least wrist extension, forearm pronation and the lowest elbow height. A keyboard opening angle in the mid-range of those tested, 15°, may provide the best balance between reducing ulnar deviation while not increasing forearm pronation or elbow separation. These findings may be useful in the design of computer workstations and split keyboards. The geometry of a split keyboard can influence wrist and forearm postures. The findings of this study are relevant to the positioning and adjustment of split keyboards. The findings will also be useful for engineers who design split keyboards.

Carpal tunnel syndrome and keyboard use at work: A population‐based study

To investigate the relationship between carpal tunnel syndrome (CTS) and keyboard use at work in a general population. A health status questionnaire was mailed to 2,465 persons of working age (25-65 years) who were randomly selected from the general population of a representative region of Sweden. The questionnaire required the subjects to provide information about the presence and severity of pain, numbness and tingling in each body region, employment history, and work activities, including average time spent using a keyboard during a usual working day. Those reporting recurrent hand numbness or tingling in the median nerve distribution were asked to undergo a physical examination and nerve conduction testing. The prevalence of CTS, defined as symptoms plus abnormal results on nerve conduction tests, was compared between groups of subjects that differed in their intensity of keyboard use, adjusting for age, sex, body mass index, and smoking status. Eighty-two percent responded to the questionnaire, and 80% of all symptomatic persons attended the examinations. Persons who had reported intensive keyboard use on the questionnaire were significantly less likely to be diagnosed as having CTS than were those who had reported little keyboard use, with a prevalence that increased from 2.6% in the highest keyboard use group (> or = 4 hours/day), to 2.9% in the moderate use group (1 to <4 hours/day), 4.9% in the low use group (<1 hour/day), and 5.2% in the no keyboard use at work group (P for trend = 0.032). Using > or = 1 hour/day to designate high keyboard use and <1 hour/day to designate low keyboard use, the prevalence ratio of CTS in the groups with high to low keyboard use was 0.55 (95% confidence interval 0.32, 0.96). Intensive keyboard use appears to be associated with a lower risk of CTS.

Electronic guitar with its keys arranged in complex array

Electronic guitar including a case, a keyboard, a sound synthesis electronic assembly and an output line. The keyboard is divided into an upper keyboard arranged on a neck of the case and a lower keyboard arranged on a body of the case. The upper and lower keyboards constitute a complex array. When a key on the upper keyboard and a key on the lower keyboard are pressed, a determined note is generated by the sound synthesis electronic assembly and can be output to a karaoke CD player. It is thus possible to play this guitar while singing the karaoke.

Electronic musical instrument providing automatic ensemble performance

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Electronic organ with a three‐finger chord and one‐finger automatic chord playing mode selector

An electronic organ provided with a selector for selecting a three-finger chord playing mode or a one-finger chord playing mode. When the three-finger chord playing mode is selected, a chord is sounded by three or four fingers on a manual keyboard or lower keyboard as in the conventional electronic organ. On the other hand, when the one-finger chord playing mode is selected, there can be automatically sounded one of chord types, such as major, minor, seventh and minor seventh chords, which have, as the root note, the note of a key being actuated on the manual keyboard. The selection of a chord type is effected by a pedal keyboard.