Impact of a poka-yoke device on job performance of individuals with cognitive impairments.

Job performance and production related issues are important not only to successful vocational training and ultimate job placement for individuals with cognitive disabilities, but also for their ability to have expanded vocational options. This study hypothesized that the application of Kaizen philosophy, and poka-yoke techniques in particular, could create job opportunities and improve productivity of individuals with cognitive disabilities. Poka-yoke or error-proofing techniques are part of the collection of Kaizen techniques. Kaizen refers to continuous improvement in performance, cost/effectiveness, and quality. Kaizen strives to empower the worker, increase worker satisfaction, facilitate a sense of accomplishment, and thereby create pride-of-work. These techniques typically reduce the physical and cognitive demands of a task and thereby render the task more accessible. The job was a fuel clamp assembly. A redesigned assembly fixture was the poka-yoke intervention. Consistent with poka-yoke principles, the intervention improved the productivity of everyone attempting the assembly. In particular, the workers in this study showed an 80% increase in productivity and an average percent error drop from 52% to about 1% after the process redesign. Furthermore, the workers showed improved morale, self-esteem, and pride-of-work. Prior to the process redesign, only the higher functioning workers could successfully perform the assembly. After the redesign a greater number of workers could successfully perform the assembly. These results not only validated the study hypothesis, but demonstrated that the success facilitated by applying Kaizen techniques had similar results with individuals with cognitive disabilities as with nondisabled workers.

Poka-yoke process controller: designed for individuals with cognitive impairments.

Poka-yoke is a Japanese term meaning "error proofing." Poka-yoke techniques were developed to achieve zero defects in manufacturing and assembly processes. The application of these techniques tends to reduce both the physical and cognitive demands of tasks and thereby make them more accessible. Poka-yoke interventions create a dialogue between the worker and the process, and this dialogue provides the feedback necessary for workers to prevent errors. For individuals with cognitive impairments, weighing and counting tasks can be difficult or impossible. Interventions that provide sufficient feedback to workers without disabilities tend to be too subtle for workers with cognitive impairments; hence, the feedback must be enhanced. The Poka-Yoke Controller (PYC) was designed to assist individuals with counting and weighing tasks. The PYC interfaces to an Ohaus CT6000 digital scale for weighing parts and for counting parts by weight. It also interfaces to sensors and switches for object counting tasks. The PYC interfaces to a variety of programmable voice output devices so that voice feedback or prompting can be provided at specific points in the weighing or counting process. The PYC can also be interfaced to conveyor systems, indexed turntables, and other material handling systems for coordinated counting and material handling operations. In all of our applications to date, we have observed improved worker performance, improved process quality, and greater worker independence. These observed benefits have also significantly reduced the need for staff intervention. The process controller is described and three applications are presented: a weighing task and two counting applications.

Electromyography interference pattern decomposition.

Decomposition of an interference pattern enables examination of individual electromyography (EMG) motor units and their firing rates at more than minimal contraction forces. In this decomposition method, significant events with a constant occurrence (near motor unit action potentials) can be enhanced, and unwanted events (distant motor unit action potentials, artifacts) eliminated, by calculating the average accumulated change while sliding a fixed-width window along the digitized EMG interference pattern. Nonparametric statistical methods are then applied to these data to determine which information is significant at the .05 level. The exact duration of significant information is identified without the need for arbitrary thresholds and filters to eliminate unwanted information. Events are then classified into groups of similar events by comparing: (1) correlation coefficients, (2) point-to-point differences, (3) amplitudes, and (4) areas. The classification is further refined by the use of firing-rate information.

Patient and staff acceptance of robotic technology in occupational therapy: a pilot study.

While the majority of applications of robotics in the field of rehabilitation focus on the development of smart aids for people without upper extremity function, there is also potential for the robot as a therapy "aide." We designed, built, and pilot-tested hardware and software that used a robot to provide muscle reeducation movement patterns after stroke. This is a report on a field trial, in which 11 occupational therapists used the system with 22 patients; each patient averaged 2.2 sessions. Based on information contained in the system database, a log, patient interviews, and therapist questionnaires, we evaluated safety, system utility, and patient and therapist acceptance. The results suggest that robotic treatment is safe and accepted (if not welcomed) by patients. The therapists expressed a qualified acceptance, suggesting several modifications to increase utility. The potential for the application of robotics in rehabilitation therapy is discussed in light of these findings.

Computerized synthesis of electromyographic interference patterns.

Computer simulation is a process that appears to have wide application in many disciplines. Electromyographic (EMG) interference patterns can be computer-synthesized by inputting parameters of individual motor unit action potentials (MUAPs) such as amplitude, duration, and phases, and recruitment parameters of number of motor units, and the firing rate and its standard deviation. The resulting simulated EMG interference patterns can then be used to test hypotheses regarding the effect of alteration of the individual MUAP parameters on the interference pattern. An example of the usefulness of simulation is demonstrated by the analysis of the simulated patterns by the Fast Fourier Transform (FFT), which indicates that the major frequency band in the FFT results from the duration of the individual phases of the MUAP. The motor unit's recruitment rate is superimposed on the FFT envelope in the low-frequency end. The variability of the firing rate influences the distinctness of the low-frequency peaks. The MUAP amplitude and number of motor units in the recruitment pattern are reflected in the FFT power. Simulation appears to be a useful tool for further investigation and development of EMG signal analysis techniques.

An automated microprocessor-controlled data collection device for use with the Technicon AutoAnalyzer system.

An automated microprocessor-controlled data collection system for use with a Technicon AutoAnalyzer in a research or clinical laboratory is described. The collection system can digitize an analog output from the AutoAnalyzer, perform mathematical operations on this digital data, detect and record peak-trough data, and perform these data acquisition and mathematical data processing operations in parallel. The data collection system can be interfaced to a variety of host computers for further data analysis. The accuracy of the data collection system was tested and compared to existing procedures using an analysis of bovine serum albumin protein. The correlation coefficient for the comparison of the results was 0.99998. Hence, the automated system is as accurate as previous methods, but is considerably faster, more efficient, and, in comparison to existing devices, less expensive.