Computers in biofeedback research and therapy

While biofeedback is being used extensively in the clinic and the laboratory, a great deal of variability exists among biofeedback users with respect to instrumentation, treatment protocols, techniques of data acquisition, and methods of data analysis. It is argued that the use of computers in biofeedback will help reduce some of this variability. Other advantages of computers in biofeedback are discussed. Several presently available automated systems are reviewed. Implications for future biofeedback research are also discussed.     

System developments in the ACT language: Towards machine independence

ACT (the Automated Contingency Translator) is a list-processing state-oriented sequence control language for on-line control and data acquisition of psychological experiments. Since 1967, ACT software has been progressively expanded and the machine base extended from the PDP8 family to the PDP9, NOVA, and the PDP11. The most recent variant of this language, designated ACT-N, removes previous arbitrary restrictions on state network complexity, expands the conversational repertoire, and adds a subset of compatible BASIC to ACT, thereby giving the package greatly increased computational powers and data storage facilities.     

The silicon-controlled rectifier as an input latch for digital laboratory computer interfaces

Several standard solutions have been developed for problems encountered when monitoring laboratory response sensors with microcomputers. These problems include voltage-level translation, power-supply isolation, contact debouncing, and temporary data storage. Data storage has typically been accomplished through the use of edge-sensitive devices, which introduce difficulties when a researcher wishes to monitor the duration of a response. A circuit is described that includes an optoisolator with a silicon-controlled rectifier at its output stage. The circuit acts as a latch for the detection of brief responses, and, because it is not edge-sensitive, it can also be used to record the duration of sustained responses.     

Data acquisition software for high data rate experiments

A computerized perceptual laboratory operates a variety of stimulus devices, including static and dynamic graphics displays, and records both discrete and analog data in a diverse and complex set of experimental paradigms. The software requirement to accommodate this variety of paradigms and high input and output data rates has been met by a single multitasked acquisition program that interprets unitary event commands to display graphics or nongraphics stimuli, record responses, control timing, or provide appropriate feedback. Event lists are created and modified with a text editor, then assembled into binary experiment definition files by dialogue with a parsing program. Graphics stimuli are referenced by a file name that contains stimulus attributes for later data extraction. All protocols and stimulus files are loaded prior to the block of trials, so no disk accesses that would delay events are required during a block. The resulting data file contains a record of all variable stimulus and timing information, as well as the discrete and analog responses, in a uniform format which facilitates data extraction.     

APCOL: A programming system for computer-controlled psychology laboratories

The development of on-line computer systems can be facilitated by higher-level programming languages that are more powerful and easier to learn than machine-level Assembly languages. In general, it is not possible to speak ofa programming language without also describing the operating system and functional problem domain of the small computer system for which it is intended. This is because of the great variety in the architecture and configuration of small computers. However, it is possible to state more general requirements and design criteria for on-line computer languages in psychology. APCOL is an example of an integrated programming system. One of the important distinguishing features of the system is that it is implemented both on the small-scale laboratory computer and on a large general-purpose computer linked to the smaller machine via a high-speed communications network. This arrangement permits firsthand access to interactive program construction with immediate test of program function by using the on-line implementation as well as access to the text-editing and mass storage facilities of the large-scale machine.     

Heterogeneity of biofeedback training effects in spasmodic torticollis: a single-case approach

Data from 184 biofeedback sessions are presented, in which 10 subjects with spasmodic torticollis had been trained to reduce pathologic activity in the hypertrophied sternocleidomastoid muscle. Each session was conducted as a single case experiment with nine successive trials. Attempts were made to distinguish motor learning processes which can be elicited independently from the biofeedback-condition from the effects of specific biofeedback information. Results showed dramatic decreases of muscle activity under biofeedback. Contrary to expectation, action potentials did not decrease across a course of 14 training sessions. Instead, effects were exhibited in an all-or-none fashion early in the training. Single-case ARIMA intervention analysis has shown that in 59% of the sessions EMG decreases demonstrated under biofeedback could be elicited prior to biofeedback in a condition of instructed control. Case studies revealed complex interactions of instructed control, specific biofeedback effects, unspecific effects of the biofeedback setting, and cognitive processes. Effects obtained within experimental sessions varied highly between subjects. Results are discussed in terms of newer concepts of basal ganglia dysfunction, and conclusions for the use of biofeedback paradigms in torticollis subjects are outlined.     

On microprocessor-based computers

Economical microprocessor-based computers have been recently developed by Motorola and Control Logic, Inc. Apparently, in response to the price competition, DEC has introduced the PDP-8/A, incorporating the memory characteristics of the microprocessor-based computers. Relative to older minicomputers, the microprocessor-based systems and the PDP-8/A “miniprocessor” require more time to execute an experimentally useful task. However, their real-time operating characteristics would appear to be sufficient for on-line use in behavioral control and data acquisition. The PDP-8/A’s compatibility with older models of the PDP-8 series enables it to use previously developed software, but, for purposes of software development, the microprocessor systems offer a more powerful architecture and instruction set.     

An instrumented method for assessment and remediation of stuttering: A single-subject case study

A single-subject experimental design was used to investigate the feasibility of applying non-invasive laboratory instrumentation for examining speech physiology to assessment and biofeedback-based remediation of stuttering. Physiologic assessment facilitated the development of behavioral goals directed at changing respiratory and phonatory behaviors for this subject. Visual biofeedback therapy produced reduction in respiratory discontinuities and increased phonatory continuity, concomitant with reduced perceivable molar dysfluency. Methods used in this case illustrate a variety of options and problems related to clinical use of instrumentation. Results suggest that signals which represent respiratory, phonatory, and articulatory physiologic events may be clinically practical for evaluating and altering perceivable dysfluency.     

Computer automation of biofeedback training

A computer-automated system has been developed for implementing response-contingent training strategies in EMG biofeedback-assisted relaxation training. An on-line minicomputer is programmed to (1) monitor progress within a training session as reflected in EMG signals; (2) compare the progress data with criteria set by the operator at the beginning of the session; and (3) on the basis of these comparisons, periodically adjust feedback gain (sensitivity) and make changes in the within-session training sequence. The system is designed to allow various adaptive training strategies to be software programmable. One of these strategies, a “shaping” procedure commonly employed in EMG biofeedback training, gradually increases the degree of relaxation necessary to produce the desired feedback signal by increasing feedback gain as the subject gets better at relaxing. Implementation of the shaping procedure is described as an illustration of system function. Current system development is guided by principles from adaptive testing and teaching systems to make more of the feedback training process adaptive in function.     

CAN-4, an advanced author language for CAI,computer-based testing and psychological experimentation: PDP-9 implementation

The effective use of computers for tutorial (programmed instruction) teaching and on-line testing requires that curriculum authors have powerful special-purpose languages. One such language, CAN-4, has been designed and implemented to run on the PDP-9. The language includes advanced scoring, data recording, computation, timing, and file control facilities. The language and its implementation are described in relation to the instructional problems which the facilities are designed to meet.     

The use of biofeedback techniques with school-aged children exhibiting behavioral and/or learning problems

This article reviews 44 studies that investigated the efficacy of biofeedback techniques in treating childhood behavioral and learning disorders. Although the data suggest that children can learn voluntary control over a variety of physiological processes, methodological flaws make it impossible to specify the mechanisms responsible for such learning. Further, the data do not suggest that biofeedback techniques are superior to more conventional treatments in remediating learning or behavioral disorders. Suggestions for future research focus upon the elimination of methodological weaknesses, the use of more stringent diagnostic criteria, and the use of more sophisticated biofeedback equipment and procedures.     

Evaluating student achievement with a relational database

Commercial database programs such as dBase and Paradox, although developed originally for business applications, are versatile and powerful tools that can be used for an academic purpose such as evaluating student performance. They can be used to write and store test questions, assemble and print classroom or on-line laboratory tests, and calculate grades, test statistics, and so forth. Databases are flexible, unlike textbook “ancillary” test bank programs that are inextricably bound to the strictly linear format and brief shelf life of specific textbook editions. A prototypical relational database program is described, with which an instructor can produce tests based on generic terms adapted from Boneau’s (1990) study of psychological literacy, as well as on behavioral learning objectives adapted from Bloom’s (1956) taxonomy of educational objectives. As a relational database, the program integrates terms, objectives, questions, tests, and test scores, and avoids unnecessary data duplication and waste of computer storage space.     

Biofeedback of slow brain potentials]

Slow cortical potentials constitute neurophysiological indicators of cortical excitability. Behaviorally they correlate with attention and motor preparation. A system for biofeedback and self-regulation of slow cortical potentials (SCP) has been developed. The portable system allows on-line visual feedback of filtered and corrected slow brain potentials in a predetermined sequence of trials. Three different algorithms for transforming the original SCP-signal into a feedback-signal have been developed and were compared in a controlled outcome study. With the optimal feedback method subjects were able to produce cortical positivity and negativity on command after three sessions. Increases and decreases of negativity of up to 20 microV were also achieved. Therefore a simple and portable PC-based device for the clinical application of SCP-biofeedback is now available.     

MacLaboratory Controller: A switch and A/D interface between Apple’s Macintosh and peripheral apparatus

Apple’s Macintosh microcomputer has advantages over other systems used for laboratory control and data acquisition, especially because of its graphic and user-friendly features. However, a major perceived limitation has been its closed architecture. We describe an interface using the RS 422 modem port that supports up to 64 input/output (I/O) functions including analog-to-digital 4–12 channel input. The Controller software supplies an easily edited authoring tool in which functional relationships, logical operators, timing (millisecond accuracy), and counting functions are established through simple mouse and menu commands. Data from I/O functions may be displayed or saved as tab-delimited files that can be opened by various Macintosh statistical and spreadsheet packages and that are transportable to some mainframe applications.     

Four process studies in the behavioral treatment of chronic headache

Four studies of ‘process’ variables in the behavioral treatment of chronic headache are examined. No relation between headache activity-level reduction and therapist variables such as level of experience (study 1) or warmth, competence or helpfulness as perceived by the patient (Study 2) was found from treatments using relaxation training and/or biofeedback. A significant relation was found, however, between regularity of relaxation practice at home (Study 4) and headache-activity reduction and between regularity of showing some degree of hand warming in thermal biofeedback treatment for vascular headache and headache activity-level reduction (Study 3). Finally, no relation was found between changes in EMG and headache activity-level for tension-headache sufferers treated with frontal EMG biofeedback.     

Using a laboratory computer for identification of nonlinear behavioral and electrophysiological systems

A system for mathematically identifying unknown nonlinear systems based upon Wiener kernels and G-functionals is presented as an example of the sophisticated analyses of electrophysiological and behavioral data made possible by the introduction of powerful digital computers to the laboratory environment. The applicability of these methods to a wide variety of systems is emphasized. By measuring the response of the unknown system to appropriate white noise stimulation, data may be obtained which are sufficient for the characterization of the system under test. The only restrictions upon the unknown system is that it be approximately stationary during the period of measurement and that its output depend upon its input in the finite past. Various pretests to evaluate the applicability of the method are presented. Simple FORTRAN programs that clarify the methods of computation are given for the preprocessing of data, the analysis of lower-order kernels, the synthesis of system response from the computed kernels, and the computation of the proportion of the variance in the systems output which is accounted for by the kernels zero, one, and two. These programs may be implemented on a digital laboratory computer of moderate size. Analysis may be performed either on-line or after data collection, depending upon the temporal characteristics of the system under test. This method represents one of the few analytical techniques presently available for the characterization of both linear and nonlinear systems. For this reason, it constitutes a uniquely powerful tool for many branches of psychology. Successful applications of this method to electrophysiological and behavioral data are mentioned. Limiting factors in the use of Wiener kernel analysis are also discussed.     

Biofeedback as a treatment for childhood hyperactivity: a critical review of the literature

Hyperactivity is a significant problem for which no causal theories have been unequivocally substantiated and one in which treatment approaches have met with limited success. Recent research in behavioral medicine has brought biofeedback into use as a treatment for disorders that are mediated by physiologic functioning, with hyperactivity as one such disorder. 36 studies are reviewed in which biofeedback was used as a treatment for hyperactivity. This review indicated that biofeedback treatments alone have not been effectively evaluated, and methodological problems with the current studies severely limit generalizations that may be made to hyperactive populations. Biofeedback in conjunction with other techniques appears to have promise for reducing some of the behavioral symptoms of the hyperactivity syndrome. Directions for further research are presented.     

Operant conditioning of epileptic neurons in monkeys and its theoretical application to EEG operant conditioning in humans

This paper reviews a series of previous reports which summarize the physiology of chronic experimental epileptic foci in monkeys. It is shown that such monkeys can be trained to bidirectionally control the firing rates of normal and epileptic neurons which comprise the epileptic focus. As a result of this acquired operant performance, the monkeys show both a decrease in clinical seizures as well as a decrease in single unit epileptic activity. The EEC correlate of this change in single unit epileptic actvity is generalized EEG desynchronization. The conclusion from these data would indicate epileptic neurons can be operantly controlled and this control is not correlated with any specific EEG pattern. This brings to question the specificity of the SMR in EEG biofeedback paradigms which treat human epilepsy. This author feels that the result from such biofeedback studies are the result of the patient learning to manipulate electrical events within the CNS pathways through which the seizure propagates and is not contingent upon specific EEG frequencies.