(Click diagram parts for more info on concepts, instruments, and methods)

The Human Performance Capacity Measurement System (HPCMS) incorporates a modular subsystem architecture.

The Human Performance Capacity Measurement System (HPCMS) has been a focal point of our efforts in the general area of "measurement tools" . The concept behind the HPCMS is itself unique and preceded the development of any individual module. This concept is based on the recognition that in any given application context, practitioners who need measurements must deal with all - or a significant part of - the total human. This provides a basis to argue against a simple collection of independent instruments, many of which may or may not be based on the same philosophy. A typical application requires the integration of many different measurements that characterize many different human subsystems.

Another major aspect of the HPCMS concept is that, regardless of the measurement scope or application context, a solution is desired that could be viewed by users as a single, integrated system. We have achieved this with a combination of modular instruments, a "plug-and-play" ability to configure any combination of these to form a customized application-specific system, and a single host computer software package that integrates control, data acquisition, and result reporting functions. For all functions, a standardized philosophy is employed across all measurements. The result is a system that is derived from a set of "first principles" (i.e., GSPT and the ERM), is easier to learn and use (than a set o independent instruments), and is more cost-efficient to produce and maintain than simply a collection of discrete instruments.

A version of the HPCMS is now commercially available from Human Performance Measurement, Inc. However, we continue to develop additional modules and software-based components that address specific performance resources. We also continue work to refine details of the basic HPCMS architecture.

The Human Performance Capacity Measurement System (HPCMS) includes modules for measurement of:

• isometric strength
• extremes/range of motion
• neuromotor channel capacity (coordination)
• tactile sensation
• steadiness (tremore)
• visual information processing speed
• memory capacity
• attention span
• postural stability
• lifting performance
• speech performance

Where applicable, these aspects of performance can be measured for most body subsystems (e.g., flexor, extensor, abductor, adductor, etc.), resulting in the ability to measure more than 400 unique performance capacities of the human system.

HPCMS - Summary of a 25 Year Development History

The current HPCMS is the result of an evolutionary effort spanning more than 25 years. Pioneering work by Potvin, Tourtellotte, Syndulko and colleagues raised the need for quantification of what they termed "neurologic function", established methods and the first subset of devices for a neuro-function laboratory, and addressed key issues such as reliability, validity, age and gender effects, and subject motivation. This laboratory was applied exclusively as a research tool, primarily in clinical trials of new drugs for progressive neurologic diseases.

A first generation computer-based system was developed which incorporated a new set of specially designed instruments capable of implementing modified versions of test items in the neuro-function laboratory as well as new items which added to the scope of the system. Moreover, research and design focus expanded to include consideration as a primary need the characterization of individual subjects (in contrast to "group study" research applications). Key questions addressed were "What should be included in such a system?" and "How should it be structured?". It was decided to place primary emphasis on items which could be viewed as being "application independent" or those items which reflected more intrinsic characteristics (e.g. strength, speed, etc.) of human subsystems. This view is contrasted with approaches which look more toward performance of the individual in relatively complex higher level tasks such as gait or activities of daily living. The rationale employed was that there are an infinite variety of such higher level tasks and combinations of them (leaving content of the measurement system always open to debate), while there is a finite set (albeit large) of the more intrinsic characteristics associated with a fairly well defined set of subsystems. A modular measurement system architecture which facilitated expandability was introduced based on recognition that:

• the human system is complex and additional measures would no doubt be required,
• each patient will likely be administered different subsets of measurements (i.e., the system would be viewed clinically as a measurement "toolbox", and
• it is highly desirable to integrate results acquired from several modules to facilitate clinical interpretation.

Second and third generation systems were developed, largely with funding from the National Institute for Disability and Rehabilitation Research. The "application-independent" philosophy and basic architecture facilitated expansion of the basic system to include modules which meet broader needs within rehabilitation (2nd generation). Simultaneous involvement of different professionals which make up rehabilitation teams (not only neurologists, but also orthopedists, physical and occupational therapists, etc.) helped to identify common denominator measurement issues across these diverse disciplines which were often hidden or confounded by different terminologies and traditions. As a consequence of these events, the name applied to describe the system evolved from "neuro-function laboratory" to "sensori-motor performance laboratory", and ultimately to "human performance". Also, the growing power of the basic "toolbox" stimulated new questions. For example, while each individual measure could easily be identified as being useful in a particular context (i.e. for documenting status or monitoring rehabilitation progress of a particular disease or injury), "What do measures mean in a bigger picture context, such as an individual's ability to drive?". The human system and its performance is complex. Despite the considerable activity in quantitative characterization, more targeted investigation of theoretical underpinnings resulted in the conclusion that a conceptual model was lacking in this and sister fields. A hierarchically organized Elemental Resource Model, based on a small but robust set of systems performance constructs, was introduced in an effort to address this issue. This not only changed the nature of our research, but also dictated the need for subtle but important transformation of measures as well as improved definition of measures and protocols under which they are acquired (third generation system).

Early generation systems were based on a DEC LSI-11/23 laboratory computer. The current system (4th generation, beginning about 1989 and remaining stable with regard to the basic architecture since) represents a transfer to a personal computer environment and the inclusion of embedded microcontrollers in each of the measurement modules. Other significant changes to the physical architecture have been implemented, further simplifying and realizing a "plug-and-play" type "systems approach" to human performance measurement.