One-handed Operation Research Articles

A Study on the Effect of Pre-cue in Simple Reactions on Control-on-Display Interfaces

Objective: This study focuses on the effects of pre-cues informing the location of upcoming visual stimulus on finger movement response in the context of control-on-display interfaces. Background: Previous research on pre-cues focus on attention allocation and motion studies were limited to indirect control conditions. The design of this study aimed to collect data on the exact landing point for finger-tap responses to a given visual stimulus. Method: Controlled visual stimuli and tasks were presented on a UI evaluation system built using mobile web standards; response accuracy and response time were measured and collected as appropriate. Among the 16 recruited participants, 11 completed the experiment. Results: Providing pre-cue on the location of stimulus affected response time and response accuracy. The response bias, which is a distance from the center of stimulus to the finger-tap location, was larger when the pre-cue was given during a one-handed operation. Conclusion: Given a pre-cue, response time decreases, but with accuracy penalized. Application: In designing touch-screen UI's - more strictly, visual components also acting as controllers - designers would do well to balance human perceptual and cognitive characteristics strategically.

Syringe and Needle Size, Syringe Type, Vacuum Generation, and Needle Control in Aspiration Procedures

Syringes are used for diagnostic fluid aspiration and fine-needle aspiration biopsy in interventional procedures. We determined the benefits, disadvantages, and patient safety implications of syringe and needle size on vacuum generation, hand force requirements, biopsy/fluid yield, and needle control during aspiration procedures. Different sizes (1, 3, 5, 10, and 20 ml) of the conventional syringe and aspirating mechanical safety syringe, the reciprocating procedure device, were studied. Twenty operators performed aspiration procedures with the following outcomes measured: (1) vacuum (torr), (2) time to vacuum (s), (3) hand force to generate vacuum (torr-cm2), (4) operator difficulty during aspiration, (5) biopsy yield (mg), and (6) operator control of the needle tip position (mm). Vacuum increased tissue biopsy yield at all needle diameters (P<0.002). Twenty-milliliter syringes achieved a vacuum of -517 torr but required far more strength to aspirate, and resulted in significant loss of needle control (P<0.002). The 10-ml syringe generated only 15% less vacuum (-435 torr) than the 20-ml device and required much less hand strength. The mechanical syringe generated identical vacuum at all syringe sizes with less hand force (P<0.002) and provided significantly enhanced needle control (P<0.002). To optimize patient safety and control of the needle, and to maximize fluid and tissue yield during aspiration procedures, a two-handed technique and the smallest syringe size adequate for the procedure should be used. If precise needle control or one-handed operation is required, a mechanical safety syringe should be considered.

The preferable keypad layout for ease of pressing small cell phone keys with the thumb.

The present study investigated the effect of keypad layout on the ease of operating small cell phones with the thumb in one-handed operations by young and elderly male and female participants. Eighteen young participants (9 males and 9 females) and 12 elderly participants (6 males and 6 females) operated 9 different keypads modeled after commercially available cordless handsets. Keypads designed by using the L9 orthogonal array differed in vertical pitch (V-Pitch: 7, 8, 9 mm) between keys, horizontal pitch (H-Pitch: 10, 11, 12 mm) between keys, the margin below the bottom row of keys (B-Margin: 5, 13, 21 mm), and phone body width (P-Width: 38, 41, 44 mm). Results concerning subjective overall usability showed the lowest scores for a V-Pitch of 7 mm and a B-Margin of 5 mm in most groups. However, for the female participants, with shorter thumbs, the increase in V-pitch did not improve operability. In the elderly participants, miskeying frequently occurred at dial keys of specific numbers. These findings suggest that the preferable keypad layout differs between different age groups and between male and female participants.

Reduced Pain of Intraarticular Hyaluronate Injection With the Reciprocating Procedure Device

Greater than 50% of patients report significant pain with intraarticular injection of hyaluronate. The reciprocating procedure device (RPD), also known the reciprocating syringe, has 2 plungers that reciprocate with each other, permitting one-handed operation. The RPD increases physician control of the needle and is proposed to reduce patient pain during syringe procedures. To determine in a randomized controlled trial whether the RPD induces less pain than the traditional syringe during intraarticular hyaluronate therapy for the knee. Eighty intraarticular injection procedures of the knee were randomized to either the conventional syringe or the RPD using hyaluronate sodium derivative (Hylan G-F-20). Outcome measures included physician's estimate of pain, patient pain (Visual Analogue Pain Scale [VAPS]), procedure duration, operator satisfaction, complications, and response to the injected medication. Patients reported 85% more pain than physicians estimated. Fifty-one percent (19/37) of subjects experienced moderate to severe pain with the conventional syringe, while only 14% (6/43) experienced pain with the RPD. The RPD reduced pain scores (RPD VAPS score: 2.12 +/- 2.15; conventional syringe VAPS score: 4.22 +/- 3.25; P < 0.001), reduced procedure time (RPD: 1.34 +/- 1.09, conventional syringe: 1.90 +/- 1.35 minutes, P < 0.001), and improved physician satisfaction (RPD VASS Score: 9.02 +/- 0.80, conventional syringe 5.69 +/- 1.33, P < 0.001). Patients have considerably more pain with intraarticular needle introduction and injectable hyaluronate therapy than physicians estimate. The RPD reduces patient pain, reduces procedure time, and improves needle introduction compared with the conventional syringe for hyaluronate injection therapy for the knee.

SMART ONE-HAND OPERATION MECHANISM FOR MULTI-PURPOSE STEERING OF A FOUR-WHEELED VEHICLE

We propose a manually controllable smart mechanism for changing locomotion types of a 4-wheeled vehicle. Our locomotion types include direct moving toward the front and rear, turning toward the right or left, and spinning, but also braking without using special disc or shoe pads. These types are possible when external motors drive locomotion power. For instance the power is supplied by a user when the vehicle is a walker. To make it easy to maneuver the walker toward the direction of the destination, we designed a joystick, which is operated by hand without using electric power or instruments. It is basically composed of a differential gear mechanism. However, it is assembled using irregular gears to satisfy the Ackerman-geometry so that the walker can turn easily with one-hand operation. We show the design of the force transmission mechanism using an irregular gear made up of two different plain gears in pitch circle diameter. Also, we show how the mechanism works since the vehicle steering is an oscillatory motion operation.

RANDOMIZED CONTROLLED TRIAL OF THE RECIPROCATING PROCEDURE DEVICE IN DEEP SYRINGE PROCEDURES.

Purpose The reciprocating procedure device (RPD) has been demonstrated to be clinically superior to the conventional syringe in deep needle and syringe procedures, including arthrocentesis, aspiration biopsy, and intra-articular injection of hyaluronate and corticosteroid. We hypothesized that this clinical superiority was due to intrinsic design characteristics of the RPD that permitted one-handed operation and enhanced control of the device by the operating physician. Materials and Methods Twenty physicians were tested for their ability to control a syringe and needle during a typical aspiration procedure with the RPD versus the traditional syringe using the validated quantitative needle-based displacement procedure model. Outcomes included unintended forward penetration (loss of control of the needle in the forward direction measured in mm), unintended retraction (loss of control of the needle in the reverse direction), and the ability to generate vacuum. Physicians operated the RPD with one hand and operated the traditional syringe alternatively with one hand and two hands. A nonoperating observer recorded all outcomes and measurements. Results The traditional syringe demonstrated a significant unintended forward penetration of 13.9 ± 2.3 mm (one-handed) and 9.02 ± 3.11 mm (two-handed). The RPD reduced unintended forward penetration to 7.39 ± 1.83 mm (a reduction of 47% and 18% respectively, p Conclusions The RPD with one hand generates vacuum more easily and is better controlled by physicians during typical interventional syringe procedures than the conventional syringe with one or two hands. The RPDs of all sizes are better controlled and superior to conventional syringes for typical interventional syringe procedures, including arthrocentesis and joint injection.

User performance with trackball-mice

Trackball-mice are devices that include both a trackball and a mouse. In this paper we discuss our experiences in building and testing trackball-mouse prototypes. We report four experiments on user performance with the prototypes used as trackball-mice, conventional mice, and in two-handed configuration with a separate trackball for the non-dominant hand. The results show that user performance with the two-handed configuration was better than in one-handed operation of a trackball-mouse and in one-handed operation of a mouse. Trackball-mouse use and conventional mouse use were more evenly matched. However, Trackball-mouse operation involves a skill that most users do not have whereas mouse operation is familiar to most. Therefore, widespread introduction of trackball-mice does not appear to be justified on performance grounds alone. However, trackball-mice can be used as regular mice by ignoring the ball. This makes them compatible with traditional graphical user interfaces while offering two extra degrees of freedom in tasks where they are beneficial.

Task Reality vs. Task Fantasy… How the Concept of Real-World Use Affects Patient Safety

<i>Task Reality vs. Task Fantasy…</i> How the Concept of Real-World Use Affects Patient Safety

Equipment

The new PosiTector 6000 now being offered by Sheen Instruments is believed to be the only low cost thickness gauge that can measure coatings on ferrous and non‐ferrous substrates using the same probe. It is a rugged, fully electronic gauge which gives measurements accurately and quickly. With a simple onehand operation, it is also ideal for use on round or curved surfaces.

A newly designed single dissector useful for laparoscopic cholecystectomy.

We developed a modified dissector capable of carrying out a one-hand operation involving three fundamental functions: grasping, sharp or blunt dissection, and dividing the tissues. With this single dissector, laparoscopic cholecystectomy can be rapidly and safely performed without changing the forceps or instruments through the trocar.

Simple device for air reduction of intussusception

A new device has been developed for pneumatic reduction of childhood intussusception. The device consists of a reusable, hand-held pressure gauge and insufflator connected to a disposable enema tip and tubing system. The assembled device permits one-handed operation which maximizes operator control of the air reduction procedure. The system has been used to evaluate 50 cases of suspected intussusception. Reduction was successful in 19 of 22 confirmed intussusceptions. This device provides a practical, simple and safe method for diagnosis and treatment of intussusception.

Optimizing a Portable Terminal Keyboard for Combined One-Handed and Two-Handed use

Human factors experimentation facilitated the design of a portable terminal keyboard for combined one-handed and two-handed operation. To ensure a comfortable grip, the terminal had to be made smaller by reducing the size of its keyboard. The product design team needed to know how small the keyboard could be before it degraded the usability of the keyboard and the overall product. The keyboard experiment was designed primarily to determine the effect of both the number of hands used in typing and key spacing on typing speed and accuracy. A total of six commercially available keyboards with key spacings varying from 0.75 to 0.45 inches were tested. Test subjects with typing skills ranging from expert to novice typed separate samples of text on each keyboard, once using one hand and once using two hands. The difference in typing speed between two and one-handed typing averaged 2—1. A key spacing less than about 0.7 inches substantially reduced typing speed but did not increase errors. Poor typists typed at roughly the same speed no matter the key spacing or number of hands used. These findings and additional human factors studies provided parameters for a keyboard smaller than standard size that is expected to allow users to achieve 90 percent of the typing speed possible on a standard size keyboard without decreasing accuracy.

The Chord Keyboard

A keyboard prototype offers one-handed operation, small size, low cost of manufacture, and permits the touch typing of large alphabets.

Low Cost Surgical Drill

A low cost cordless electric drill originally designed for the home workshop has been adapted for use in the operating room and extensively employed for over a year. Permitting one-hand operation, unencumbered by power cords or air hoses, and positively free from shock hazard, this type of drill will perform the majority of drilling tasks needed by the orthopedic surgeon. The cost compares with many currently used "disposable" operating room items.

Forces That May Be Exerted by Man in the Operation of Aircraft Door Handles

Six handle configurations were tested by 8 male subjects on a test arrangement simulating an aircraft door. The torques exerted by the subjects were measured in angular increments of 45°. Over 1200 static and dynamic measurements were made. A limited check study on 10 females, totaling 120 measurements, was also made. The shape, length, direction of movement, arc of motion, effects of one-handed operation, maximum torques and differences between sexes are discussed.