Keyboard Tasks Research Articles

Assessing the Preservation of Lumbar Lordotic Curvature in Everyday Sitting Conditions Assessed with an Inertial Measurement System.

Background/Objectives: Lumbar lordotic curvature (LLC), closely associated with low back pain (LBP) when decreased, is infrequently assessed in clinical settings due to the spatiotemporal limitations of radiographic methods. To overcome these constraints, this study used an inertial measurement system to compare the magnitude and maintenance of LLC across various sitting conditions, categorized into three aspects: verbal instructions, chair type, and desk task types. Methods: Twenty-nine healthy participants were instructed to sit for 3 min with two wireless sensors placed on the 12th thoracic vertebra and the 2nd sacral vertebra. The lumbar lordotic angle (LLA) was measured using relative angles for the mediolateral axis and comparisons were made within each sitting category. Results: The maintenance of LLA (LLAdev) was significantly smaller when participants were instructed to sit upright (-3.7 ± 3.9°) compared to that of their habitual sitting posture (-1.2 ± 2.4°) (p = 0.001), while the magnitude of LLA (LLAavg) was significantly larger with an upright sitting posture (p = 0.001). LLAdev was significantly larger when using an office chair (-0.4 ± 1.1°) than when using a stool (-3.2 ± 7.1°) (p = 0.033), and LLAavg was also significantly larger with the office chair (p < 0.001). Among the desk tasks, LLAavg was largest during keyboard tasks (p < 0.001), followed by mouse and writing tasks; LLAdev showed a similar trend without statistical significance (keyboard, -1.2 ± 3.0°; mouse, -1.8 ± 2.2°; writing, -2.9 ± 3.1°) (p = 0.067). Conclusions: Our findings suggest that strategies including the use of an office chair and preference for computer work may help preserve LLC, whereas in the case of cueing, repetition may be necessary.

Effect of sit-stand workstation position and computer task on head and trunk postural sway and discomfort

Adjustable-height desks may provide musculoskeletal health benefits to offset the effects of prolonged sitting. One mechanism may be increased postural variability, here characterized by head and trunk postural sway. Linear acceleration of the head and trunk were measured while participants used computer workstations in seated and standing positions during keyboard and mouse tasks; secondary measures were discomfort and proprioception (head and neck repositioning error). Median accelerations of the head and trunk were 20–26% lower in mouse tasks compared to keyboard tasks (p < 0.01). There were no significant differences in sway parameters between seated and standing positions. Discomfort and proprioception were correlated; subjects who experienced increased neck discomfort after 1.5 h of computer work had almost twice the head and neck repositioning error. The results suggest that postural sway is more affected by different tasks (keyboard vs. mouse) than by different workstation configurations and that low proprioception acuity may relate to the development of discomfort.

Measuring cognitive flexibility in anorexia nervosa: Wisconsin Card Sorting Test versus cued task-switching

PurposeThe Wisconsin Card Sorting Test (WCST) is the most common measure of cognitive flexibility in anorexia nervosa (AN), but task-switching paradigms are beginning to be utilized. The current study directly compared performance on a cued task-switching measure and the WCST to evaluate their association in participants with a lifetime diagnosis of AN, and to assess which measure is more strongly associated with clinical symptoms.MethodsForty-five women with a lifetime diagnosis of AN completed the WCST, cued color-shape task-switching paradigm, Anti-saccade Keyboard Task, Running Memory Span, Eating Disorder Examination Questionnaire, Depression Anxiety Stress Scales short form and Eating Disorder Flexibility Index.ResultsThere was no evidence of a significant association between WCST perseverative errors and cued task-switching switch costs. Results suggest lower working memory capacity is a determinant of higher perseverative error rate. When controlling for mood variables, neither cognitive flexibility measure was a significant independent predictor of symptom severity.ConclusionsResults provide support for previous suggestions that WCST perseverative errors could occur due to difficulties with working memory, sensitivity to feedback, and issues with concept formation. Cued task-switching paradigms may provide a useful measure of cognitive flexibility for future eating disorders research by reducing task-specific confounds.Level of evidenceLevel III Case–control analytic study.

Motion and Gesture Controlling

Hand gesture is an innovative technique of interaction between human and computer. Hand gesture recognition is a technology that is becoming increasingly relevant, given the recent growth and popularity of Virtual and Augmented Reality technologies. In this paper, we represent a novel approach for better human computer interaction (HCI) where we are using hand gesture recognition using real-time camera in order to overcome the drawbacks of existing methods and more user friendly. Our method is to use a camera and computer vision technology, such as image segmentation and gesture recognition, to control keyboard tasks and Hand motions are acquired using web camera based on color detection.

Why Are Sequence Representations in Primary Motor Cortex So Elusive?

In this issue of Neuron, Yokoi and Diedrichsen (2019) use a finger keyboard task to show that sequences are widely represented across cortex but that only single elements are represented in primary motor cortex. These results suggest that sequence tasks primarily probe the ability to order discreet actions rather than to execute a skilled continuous sequential action.

Size Effects on the Touchpad, Touchscreen, and Keyboard Tasks of Netbooks

The size of a netbook plays an important role in its success. Somehow, the viewing area on screen and ability to type fast were traded off for portability. To further investigate, this study compared the performances of different-sized touchpads, touchscreens, and keyboards of four-sized netbooks for five application tasks. Consequently, the 7" netbook was significantly slower than larger netbooks in all the tasks except the 8.9" netbook touchpad (successive selecting and clicking) or keyboard tasks. Differences were non-significant for the operating times among the 8.9", 10.1", and 11.6" netbooks in all the tasks except between the 8.9" and 11.6" netbooks in keyboards tasks. For error rates, device-type effects rather than size effects were significant. Gender effects were not significant for operating times in all the tasks but for error rates in touchscreen (multi-direction touching) and keyboard tasks. Considering size effects, the 10.1" netbooks seemed to optimally balance between portability and productivity.

A portable and low-cost assistive computer input device for quadriplegics

A useful assistive computer input device owning keyboard and mouse functions designed to assist quadriplegics is proposed in this paper. Users can operate the computer through a nipple switch with Morse code encoding. Because of the difficulty with keeping a stable typing speed and ratio of Morse code, the fuzzy algorithm is applied to solve this problem, as it recognizes the unstable Morse code. The proposed device is mainly constructed with a microcontroller, which implements several tasks: 1) Universal Serial Bus (USB) task; 2) Mouse task; 3) Keyboard task; 4) Morse code task. Since the proposed device only needs a few common components, we can lower the cost of the proposed device and design it to reach a small size (50 × 25 × 10 mm) in accordance with actual requirements. In our experiment, the three subjects, quadriplegics, who had been trained in three days could smoothly operate the functions of the mouse and could type at least 15 English letters per minute after a course of two weeks training. With the increase of training time, the fastest typing speed one of the subjects could achieve was 63 English letters per minute. This device is one of the most convenient assistive computer input device for quadriplegics.

Physical exposure differences between children and adults when using standard and small computer input devices

By the age of five years, 75% of the children in the USA are using computers and at this age they are only one-half to two-thirds the size of and about one-fifth as strong as their adult counterparts. Fourteen children between five and eight years of age and their same-gender biological parents (giving a total of 28 subjects) were evaluated using both a standard and a smaller, child-proportional input device during standardised mouse and keyboard tasks. Typing and computer mouse performance were measured with tracking software, wrist posture was measured with an electrogoniometer and electromyography was used to measure finger flexor and extensor muscle activity in the right arm. With the small mouse, both children and adults performed the mouse task significantly faster and made significantly fewer errors. When using the standard-sized mouse and keyboard, children worked with significantly greater ulnar deviation and significantly less extension than their adult counterparts. When children used the smaller mouse, finger flexor muscle activity, finger extensor muscle activity and ulnar deviation significantly decreased, with little change in wrist extension compared to the standard mouse. No significant differences were observed between the standard and small keyboards for children or their parents. Compared to their adult counterparts, children had to apply twice the relative force, as a percentage of their maximum capacity, to activate the buttons and keys on the input devices. These measured differences may have application in the design of computer input devices for children.

Validation of the Revised Child Version of the Assessment of Computer Task Performance

Objective. The purpose of this study was to examine test-retest reliability, internal consistency, and construct validity of the revised child version of the Assessment of Computer Task Performance. The subjects were 155 children of 5 to 11 years of age who did not have any visual or motor impairment. Children 5 through 9 years of age were administered the revised test, which included some additional tasks. Children 10 and 11 years of age were administered selected tasks from the adult version. A subgroup of 52 children were administered the test for the second time to examine test-retest reliability. Intra-class correlations for the mean time to complete two trails indicated moderate to good test-retest reliability (0.66–0.91). The alpha coefficient for tasks administered to children 5 through 9 years of age (0.85) supports internal consistency. Removal of one task increased the alpha coefficient to 0.79 for tasks administered to children 10 and 11 years of age. Three factors explained 84% of the total variance in scores of children 5–9 years of age and 75% of the variance in scores of children 10 and 11 years of age. The mean time to complete keyboard tasks decreased with age and the mean time to mouse tasks decreased between 5 and 9 years. Conclusion. The results provide evidence of test-retest reliability, internal consistency, and construct validity of the revised Assessment of Computer task Performance.

Performance degradation under pressure in music: an examination of attentional processes

An experiment was carried out to investigate the cognitive mechanisms responsible for performance degradation under pressure in music. The experiment was designed to compare the predictions of two theories, distraction and explicit monitoring. Distraction theory (Eysenck, 1992) explains performance degradation as a result of attentional shifts to task-irrelevant information. Explicit monitoring theory (Baumeister, 1984; Masters, 1992) postulates that performance degradation is due to increased attention to step-by-step control of skill processes. A total of 72 novice musicians were given individual lessons on basic note and rhythm reading skills. They were then trained on a keyboard task under one of three conditions (single-task, dual-task, video-monitoring) before being exposed to either a high-pressure or low-pressure post-test. Results showed that pressure led to skill failure in the single-task and dual-task groups, but resulted in improved performance of the video-monitoring group. These results were consistent with explicit monitoring theory. Furthermore, video-monitoring training was found to ameliorate the performance deficits normally caused by high pressure. Finally, the present study found no evidence that trait anxiety influences the effect of pressure on performance.

Outside Directors and Corporate Board Decisions: A Natural Experiment

During the 1990s, the global economy appears to have suffered an outbreak of director mania - at least 18 countries have witnessed publication of guidelines that stipulate floors for the representation of outside directors on corporate boards. The apparent (largely untested) premise underlying this movement is that boards with significant outside directors will make different (and perhaps better) decisions than boards dominated by inside directors. As the first-mover in this movement, the U.K. provides a laboratory for a natural experiment to examine this presumption empirically. We investigate one key board task - the appointment of the CEO - to determine whether boards are more likely to appoint an outside CEO after they have increased the representation of outside directors to comply with the exogenously imposed standards. We find that the (coerced) increase in outside directors does alter the CEO selection decision. Additionally, announcement period stock returns indicate that the decisions are not only different, they also appear to be better.

A Comparison of Wrist Posture and Forearm Muscle Activities While Using an Alternative Keyboard and a Standard Keyboard

The wrist posture associated with the use of the conventional “QWERTY” keyboard is a risk factor for work-related musculoskeletal disorders in the upper limbs. Newly designed keyboards have been produced with the aim to reduce the strain in the wrist and forearm region. The present study compared the effects of using a standard keyboard and a split/angled keyboard on the forearm muscle activities and wrist joint angles. Ten subjects (6 males and 4 females) performed a standard keyboard task for 30 min, using each of the two keyboards while wrist joint angles and electromyography (EMG) were recorded. Wrist extension and ulnar deviation angles were both significantly reduced with the split/angled keyboard (p = .030 and .010), and lower EMG activities were recorded in the extensor carpi radialis and ulnaris muscles. The present results implied that the split/angled keyboard may be a better instrument for prolonged keyboard operation, resulting in reduced strain in the wrist and forearm region.

Usefulness of Power Spectral Analysis for Measurement of Local Muscle Fatigue during Keyboard Task

Usefulness of Power Spectral Analysis for Measurement of Local Muscle Fatigue during Keyboard Task

Keyboard reaction force and finger flexor electromyograms during computer keyboard work.

This study examines the relationship between forearm EMGs and keyboard reaction forces in 10 people during keyboard tasks performed at a comfortable speed. A linear fit of EMG force data for each person and finger was calculated during static fingertip loading. An average r2 of .71 was observed for forces below 50% of the maximal voluntary contraction (MVC). These regressions were used to characterize EMG data in force units during the typing task. Averaged peak reaction forces measured during typing ranged from 3.33 N (thumb) to 1.84 N (little finger), with an overall average of 2.54 N, which represents about 10% MVC and 5.4 times the key switch make force (0.47 N). Individual peak or mean finger forces obtained from EMG were greater (1.2 to 3.2 times) than force measurements; hence the range of r2 for EMG force was .10 to .46. A closer correspondence between EMG and peak force was obtained using EMG averaged across all fingers. For 5 of the participants the force computed from EMG was within +/-20% of the reaction force. For the other 5 participants forces were overestimated. For 9 participants the difference between EMG estimated force and the reaction force was less than 13% MVC. It is suggested that the difference between EMG and finger force partly results from the amount of muscle load not captured by the measured applied force.

Backward versus Forward Chaining in the Acquisition of a Keyboard Skill

Although backward chaining has been found superior to whole-task training, the effect might depend on the ordering of difficult and easy segments of the task, and forward chaining requires investigation. The experiment uses a musical keyboard task to test these possibilities, counterbalancing difficulty order with direction of chaining in a comparison with whole training. Performance was scored for melodic errors and for rhythmic accuracy and consistency. Both of the part-task methods proved superior to the whole method during training trials, in criterion trials on the whole task, and during retention after one week. However, forward chaining conferred a greater advantage than backward chaining on most measures. The results weaken several explanations for the superiority of backward chaining but confirm the advantages of segmentation methods in part-task training.

Directional Errors and Their Correction in a Discrete Tracking Task

Abstract Several recent studies have indicated the characteristics of error and error correcting reaction times in choice reaction tasks involving ungraded keyboard tasks. At the same time, models of error detection and correction have been proposed, none of which can exclusively account for all the results. In this paper a detailed analysis was made of errors and their correction which were found in a discrete tracking task where the movements were graded and performed with one anatomical unit. Records were obtained of displacement, acceleration and muscle activity underlying the responses. In common with the keyboard results, the errors were typified by relatively short reaction times. They were corrected in the absence of any specific error feedback and the stimulus to which the response should originally have been made. As a result of the sensitivity for the acceleration measures, so-called error correcting reaction times were observed which were considerably shorter than those previously reported. A ...

A comparison of neurological and psychiatric patients on a serial discrimination keyboard task.

A comparison of neurological and psychiatric patients on a serial discrimination keyboard task.

Looking, sequential redundancy, transfer, and age in early keyboard learning.

Groups of older and younger subjects were given one-hour sessions on a simple keyboard task. In the first experiment the major variable was the extent to which subjects could see what they were doing while carrying out a 5- or 10-alternative task. In the second experiment subjects performed the task with a positional or an alphabet in-line display using either a completely random or a structured input sequence. In the third experiment, the effect of pre-training on a positional display on subsequent performance with an alphabet in-line display was examined. It was found that both older and younger subjects made more errors when they could not see either keyboard or their hands; that older subjects could take advantage of sequential redundancy only when using an alphabet in-line display; and that older subjects did not benefit from positional display pre-training.

THE DEVELOPMENT OF A KEYBOARD TRAINING SITUATION IN MINIATURE

In this paper, the author describes progressive changes which have taken place in a methodology for the study of keyboard tasks. The S–R relationships progressed from a laboratory abstraction to one having high face validity; practice was extended from a single session to programmes in which two sessions were given on each of ten days; and the relationship between the experimenter and the subjects became increasingly similar to that found in actual training situations. These changes are illustrated by examples drawn from the author's work. It is claimed that increasing the general face‐validity of the laboratory approach may enhance the possibilities of studying ‘pure’ problems.