Treatment of aggressive behavior: The effect of EMG response discrimination biofeedback training

Journal o f Autism and DevelopmentalDisorders, Vol. I0, No. 2, 1980

Treatment of Aggressive Behavior: The Effect of EMG Response Discrimination Biofeedback Training'

Howard Hughes and Ronald Davis North Texas States University

This N of 1 study utilizes a withdrawal design with aggressive responses of a 27-year-old male exhibiting autistic behavior. The frequency of physical and verbal aggressive responses was decreased by reinforcing attempts to relax (utilizing EMG biofeedback) when discriminitive stimuli for aggressive behavior were present.

Inappropriate aggressive and disruptive behavior in the mentally handicapped has been recognized as a significant problem. Some of the methods that have been used to control these behaviors in human beings are electric shock (Lovaas, Shaeffer, & Simmons, 1965; Ludwig, Marx, Hill, & Browning, 1969), time-out from reinforcement (Bastow & Bailey, 1969; Porterfield, Jackson, & Risley, 1976; Wolf, Risley, & Mees, 1964), and restraint (Hamilton, Stephens, & Allen, 1967). Though effective in controlling such behavior, these procedures have c~rtain drawbacks, in- cluding negative public reactions, punishment-induced aggression (Ulrich & Azrin, 1962), and therapist unwillingness to use these procedures (Foxx & Azrin, 1972).

Attempts are now being made to develop alternative procedure to control aggressive and disruptive behavior. Foxx and Azrin (1972) have used an overcorrection procedure to reduce aggressive behavior of retarded and brain-damaged patients. Similarly, Webster and Azrin (1973) used

'The authors wish to thank Janet Ellis and Rick Crawford for assistance in completing the research, and Dr. Donald Whaley, executive director of the Center for Behavioral Studies, Denton, Texas, for his and the center's cooperation.

193 0162-3257/80/0600-0193 $03.00/0 �9 1980 Plenum Publishing Corporation

194 Hughes and Davis

required relaxation to decrease agitative, disruptive behavior in retarded persons. In another study, EMG biofeedback was used to aid in the reduction of self-injurious behavior of severely retarded individuals (Schroeder, Peterson, Solomon, & Artley, 1977). EMG biofeedback has also been utilized effectively with hyperactive (Braud, Lupin, & Braud, 1975) and cerebral palsy populations (Finley, Niman, Standley, & Wansley, 1977).

The purpose of the present study was to investigate the efficacy of utilizing electromyographic (EMG) feedback training to facilitate control of aggressive and disruptive behaviors in a person exhibiting autistic behaviors. An attempt was made to decrease the frequency of physical and verbal aggressive responses by reinforcing the emission of a competing response (attempting to relax) utilizing EMG feedback. The EMG feedback was presented during the discriminative stimuli for aggressive behavior.

M E T H O D

Subject

The subject was a 27-year-old, mentally retarded male who exhibited autistic behaviors as defined by Lovaas (1967) and Koegel (1972). These included severe behavioral deficits accompanied by ritualistic, self- stimulatory, and often self-destructive behavior. The subject demonstrated a limited vocabulary but was able to carry on a conversation. He could read, write, spell, and solve math problems at a third-grade level. He had a history of severely disruptive and aggressive behavior, such as hitting and kicking others, batting with his head, and throwing objects. There was also a history of verbal disruptive responses consisting of "shut up" and several obscene words. At the time of the present study, the subject would shout "shut up" or obscene words, hit, or throw objects. These conditions occurred when someone coughed, when he was having difficulty with a task, when someone told him he was wrong or mistaken, or when someone attempted to help him with a task.

Apparatus

The BFT EMG 401 System (Bio-Feedback Technology, Inc., Garden Grove, California) was used to monitor and to feed back to the subject muscle tension levels. The system consists of two instruments: the feedback myograph (BFT EMG 401) and the time-period integrator (BFT 215 TPI).

Response Discrimination Biofeedback Training 195

The feedback myograph senses muscle-produced electrical activity through three silver/silver chloride electrodes (6.5 mm in diameter) placed approximately l inch (2.5 cm) above the eyebrows and spaced 1 V2 inches (3.75 cm) apart on the subject's forehead. The EMG 401 amplifies the detected signal and provides both audio information feedback and an electrical signal to the subject that is displayed visually by the time-period integrator. Auditory feedback is provided to the subject via headphones or speaker such that a tone varies in pitch in direct proportion to the degree of forehead muscle tension present. The higher the pitch of the tone, the higher the muscle tension present.

The BFT TPI 215 receives the amplified EMG 401 signal, averages it over a selected time period (10-120 seconds), and provides a digital visual readout between 0 and 99.9 microvolts root mean square (#v).

A reclining chair was utilized that offered an upright position and intermediate and full reclining positions.

Materials

Data sheets were prepared to record the date, number of aggressive responses, and EMG /~v readings within any particular time interval. An academic program was constructed that could be administered verbally. The program consisted of three stories, each of approximately 250 words, that could easily be understood by a third-grade student. Following each story were 10 very difficult questions (i.e., the subject obtained no correct answers to these questions upon the first administration) and 16 less difficult questions (i.e., the subject answered all questions correctly upon the first administration).

Procedure

EMG #v readings were recorded at 10-second intervals from the digital readout of the time-period integrator throughout the experimental baseline, training and intervention phases.

The number of physical and/or verbal aggressive responses were recorded during the baseline and intervention phases.

An aggressive response was defined as any part of the subject's body coming into contact with another part of his body, an object, or another person, with enough force as to be detected by two experimenters; pushing or throwing any object with his hand; or verbalizing the phrase "shut up" or any obscenity loudly enough to be audibly detected by two experimenters. Both physical and verbal aggression were considered part of the same


func t iona l response class because bo th followed the same st imuli (negative verbal feedback) and were inappropr ia te .

One exper imenter recorded the n u m b e r of aggressive responses occurr ing within a given 10-second interval and also the E M G #v readout

for the same interval . A second exper imenter recorded the n u m b e r of aggressive responses occurr ing as a result of present ing the subject with the aversive s t imulus that , for the present s tudy, was telling him that he had answered a par t icular ques t ion incorrect ly. There were 16 quest ions of a low

level of diff icul ty and 10 quest ions of a high level of diff icul ty presented at each session. The order of p resen ta t ion of the two sets of quest ions was coun te rba l anced over trials. Posit ive exper imenter responses to the sub- jec t ' s answers were adminis te red fol lowing 6 easy quest ions to guard against

suppress ion of answers to ques t ions by the subject . The percentage of agreement between experimenters on the f requency of aggressive responses occurr ing across all pos tques t ion 10-second intervals was computed as an index of reliabili ty.

The invest igat ion was conduc ted in five phases (see Table I). Phase 1 consisted of four sessions. Each session consisted of one exper imenter reading a story to the subject and asking him 26 quest ions over its c o n t e n t - - 1 0

quest ions of high-level diff icul ty and 16 quest ions of low-level diff icul ty

Table I. Brief Summary of Procedures

Phase 1 (Baseline)--4 sessions During each session the experimenter read a story to the subject and asked him 26 questions over its content: 10 questions of high-level difficulty and 16 questions of low-level difficulty introduced in random order. Upon answering each question he received either positive or negative feedback (i.e., the positive or negative stimulus)

Phase 2 (EMG biofeedback training)--5 sessions The subject was asked to lower the pitch of the auditory feedback tone by closing his eyes and attempting to relax. He was instructed that he would receive pennies for lowering the pitch of the tone.

Phase 3 (Response discrimination training)--3 sessions The subject was trained to attempt to lower the feedback tone when it was intermittently presented. Audible lowering of the tone resulted in verbal praise from the experimenter. If the tone-on reading was 1 or more units lower than the preceding final tone-off reading, the subject received additional praise and a penny.

Phase 4 (Intervention)~ sessions The procedures utilized included those of Phase 1. In addition, the presentation of auditory feedback with instructions to lower its pitch was presented immediately upon his answering a question, thus coinciding with the subject's receiving either the positive or the negative stimulus.

Phase 5 (Return to baseline)--6 sessions This phase consisted of a return to baseline as in Phase 1.


introduced in random order. Every story and associated questions were used in each phase. Contingent upon the subject's answers to 20 questions (10 of high-level difficulty and 10 of low-level difficulty), the experimenter stated to the subject, "You got that question wrong," which was the stimulus for aggressive responses to occur. Following the subject's answers to 5 of the questions of low-level difficulty, the experimenter stated, "You got that question r ight ." The positive experimenter responses were introduced within the 16 questions of low-level difficulty. After the experimenter introduced his response to the subject's answer to each question, a minimum of 10 seconds elapsed before the next question was asked. EMG tzv recordings were recorded for each of these 10-second intervals, and the number of aggressive responses were recorded within each interval and for each kind of question asked. The subject received no aud,io feedback during this phase.

Phase 2 consisted of five sessions, each 1 hour in length, to train the subject to lower his tension level via audio feedback. At the beginning of each of these sessions, the EMG electrodes were attached to the subject's forehead, and he was placed in either the intermediate or the full reclining position in the reclining chair. The room lights were turned off, and it was explained to him that the more relaxed he became, the lower the pitch would become. The experimenter then instructed him to close his eyes and to bring down the pitch of the tone. In addition, the subject was instructed that he would get pennies for lowering the pitch of the tone.

During the first three 1-hour sessions, earphones were used to deliver the audio feedback to the subject. During the last two sessions, an audio speaker was used to deliver the audio feedback.

To facilitate generalization, the relaxation response to the EMG feedback was elicited successively under the following conditions: the subject reclined with his eyes closed and the room lights off; the subject reclined with his eyes open and the room lights off; the subject was in a sitting position with eyes closed and room lights on; the subject was in a sitting position with eyes open and room lights on. The subject was offered verbal praise and a penny at the end of each 10-second interval in which the EMG readout decreased 1 or more units (1/10 of a/~v) lower than the previous 10-second- interval readout throughout the training phase.

Response Discrimination Training

Phase 3 consisted of three sessions, each lasting 1 hour, in which the subject was trained to attempt to lower the pitch of the audio feedback when it was present. Throughout this phase, the subject was in an upright sitting position with his eyes open and the room lights on. A speaker was


used to deliver audio feedback. The audio feedback was intermittently turned from the " o f f " to the " o n " position. At the beginning of the tone- on condition, the experimenters would instruct the subject to lower the audio feedback pitch as soon as it was present. He would then verbally praise the subject for any audible lowering of the tone. The final 10-second- interval EMG reading before the tone-one condition was recorded. The first 10-second-interval reading during the tone-on condition was also recorded. If the tone-on reading was 1 or more units lower than the preceding final tone-off reading, the subject would receive additional praise and a penny.

During the second and third sessions of this phase, the reading of stories and asking the subject questions over their content were faded into the session. First, only the stories were read. Following this, the experimenter began asking more and more questions after the reading of the stories. During this procedure, the subject was not required to answer any of the questions that were asked. Also, during this fade-in procedure, intermittent tone-on conditions were continued, with verbal praise and pennies used as reinforcers for any available lowering of the feedback tone by the subject. Total time for the fade-in procedure was 1 hour and 20 minutes.

Intervention

Phase 4 included the procedures present during Phase 1. In addition, a speaker was utilized to provide the subject with audio feedback. While the program story was being read to the subject, intermittent tone-on conditions were introduced, as in Phase 3. The audio feedback was not present until the subject gave an answer to a question asked by the experimenter. Contingent upon his answer, the audio feedback was presented, and one experimenter instructed him to lower its pitch. This was simultaneous with the other experimenter presenting either negative ("You got that question wrong") or positive ( "You got that question r ight") stimuli. The subject was offered verbal praise and a penny after each 10-second tone-on condition with an EMG reading 1 or more units lower than the reading for the preceding tone-off condition. After the cessation of each 10-second tone-on condition, another question was read to the subject. EMG/~v readings were again recorded for all 10-second intervals. Aggressive responses were recorded within each 10-second interval.

Phase 5 consisted of a return to baseline as in Phase 1. Due to circum- stances beyond the experimenters' control, there was a l -month break between the second and third sessions in this phase.


RESULTS

There was 95~ agreement between experimenters on the frequency of aggressive responses occurring across all postquestion 10-second intervals. Phases 2 (EMG feedback training) and 3 (response discrimination training) were training only, and behavior was shaped in such a manner that no aggressive behavior occurred.

Presented in Figure 1 are the number of aggressive responses occurring during initial baseline, intervention, and return-to-baseline phases. There was a marked decrease in aggressive responses during intervention. The average number of aggressive responses occurring during initial baseline was 19; they decreased to 6.25 during intervention. A large initial increase in aggressive responses occurred upon return to baseline, then the rate stabilized at a somewhat higher level average of 13 aggressive responses during intervention. However, the rate did not return to the level of initial baseline. This indicates some generalization of the intervention effects.

Figure 2 presents (a) the mean EMG/zv levels for 10-second intervals where one or more aggressive responses occurred and (b) the mean EMG #v

35 - Baseline Treatment Baseline

3O w Z

~ - 25

20

,qg

-" 10

z 5

0 i i i I i i i1 'o il i2 1'3 SESSIONS

Fig. 1. Number of aggressive responses exhibited by the subject during baseline, treatment , and return to baseline.

200 H u g h e s and Dav i s

35 Baseline

30

25

2O

15

10

5

Treatment Basel ine

0' i ) i i SESSIONS

Intervals in which cllressive responses occurred

:- : Intervals precedie[ intervals in which a[ILressivo responses occurred

i I 1 I 1 I 10 I1 12 13 14

Fig. 2. Average muscle tension levels during intervals when aggressive responses occurred during baseline, treatment, and return to baseline.

levels for intervals immediately preceding 10-second intervals where one or more aggressive responses occurred.

There was a decrease in mean EMG/~v from initial baseline during intervention for both intervals. The decrease appeared greater for the intervals where aggressive responses occurred than for intervals preceding aggressive response occurrence. There was some increase in mean E M G #v f rom intervention upon return to baseline, with less fluctuation in EMG #v levels for the first four sessions of return to baseline than mean EMG #v for the last two sessions of return to baseline. I f compared with the correspond- ing sessions of Figure 1, it becomes apparent that the mean EMG #v increase was not accompanied by a parallel increase in the number of aggressive responses occurring. Also, in the first session of return to baseline, there was a sharp increase in aggressive responses without a parallel increase in mean EMG ttv. This may indicate that when the subject was instructed by the experimenter to lower the E M G #v (during intervention), there was a relationship between the frequency of aggressive response occurrence and E M G #v. However , this relationship did not seem to hold when such instructions were not for thcoming (which was the case in both initial baseline and return-to-baseline phases).


In comparing the intervention phases of Figures l and 2, it appears that there is a covariation between a decrease from initial baseline sessions in mean EMG #v and the frequency of aggressive responses. Such a parallel decrease would seem to indicate that the response of lowering the EMG #v is effective in decreasing aggressive behavior.

DISCUSSION

The results of this investigation seem to indicate that the present treatment is relatively effective in reducing physical and verbal aggressive responses in a person exhibiting autistic behavior. There was an appreciable reduction in aggressive responses during intervention. Some improvement was retained upon cessation of intervention, following temporary return of aggressive responses (possibly extinction induced aggression). This effect cannot be accounted for in terms of competing responses of relaxing tension in the frontalis muscle. Although there appears to be some reduction in EMG, it is not consistently, inversely correlated with aggressive responses. Additional research is needed to identify the effective component in this treatment procedure. A multiple-baseline design might be used in lieu of or in addition to a withdrawal design to identify the effect of intervention.

The authors hypothesize that the major competing response is likely to be attempting to relax (i.e., remaining still, eyes closed, not talking, etc.). This could be assessed in future research by defining and collecting data on behaviors indicative of relaxation attempts to see if they are inversely related to aggressive responses. Furthermore, it is hypothesized that the procedure could be improved by gradually expanding the number of rein- forced behaviors so that it gradually becomes a DRO schedule. In addition, control procedures should be utilized to assess the contribution of habitua- tion alone (i.e., the continued presentation of a stimulus for aggression), a DRO schedule, and a combination of DRO and the procedure utilized in the study.

If this analysis is correct, the point arises as to why one would use EMG biofeedback training as the major response in this procedure as opposed to a more simple procedure such as deep breathing or counting to 10. In the authors ' opinion, any culturally acceptable response that the client and therapist find plausible in the treatment of aggressive behavior would likely be effective for that client. It would be desirable that the response not be disruptive to ongoing social behavior (e.g., counting to I0 covertly and breathing deeply would appear less disruptive than counting aloud). In this regard, a biofeedback-established relaxation-attempting response would seem to comply with these criteria.


R E F E R E N C E S

Bastow, D. E., & Bailey, J. B. Modification of severe disruptive and aggressive behavior using brief time-outs and reinforcement procedures. Journal o f Applied Behavior Analysis, 1969, 2, 31-38.

Braud, L. W., Lupin, N., & Braud, W. G. The use of EMG (electromyographic) biofeedback in the control of hyperactivity. Journal o f Learning Disabilities, 1975, 8, 420-425.

Finley, W. W., Niman, C. A., Standley, J., & Wansley, R. A. Electrophysiologic behavior modification of frontal EMG in cerebral-palsied children. Biofeedback and Self- Regulation, 1977, 2, 59-74.

Foxx, R. M., & Azrin, N. H. Restitution: A method of eliminating aggressive-disruptive behavior of retarded and brain-damaged patients. Behaviour Research and Therapy, 1972, 1, 305-312.

Hamilton, J., Stephens, L., & Allen, P. Controlling aggressive and destructive behavior in severely retarded institutionalized residents. American Journal of Mental Deficiem3,, 1967, 1,852-856.

Koegel, R. L. The relationship of self-stimulation to learning in autistic children. Journal of Applied Behavior Analysis, 1972, 5. 381-387.

Lovaas, O. I. A behavior therapy approach to the treatment of child schizophrenia. In J. Hill (Ed.), Minnesota symposium on child psychology. Minneapolis: University of Minne- sota Press, 1967. Pp. 108-159.

Lovaas, O. I., Schaeffer, B., & Simmons, J. Q. Building social behavior in autistic children by the use of electric shock. Research in Personality, 1965, 1, 99-109.

Ludwig, A. M., Marx, A. J., Hill, P. A., & Browning, R. M. The control of violent behavior through faradic shock. Journal of Nervous and Mental Disease, 1969, 148, 624-637.

Porterfield, J. K., Jackson, E. H., & Risley, T. R. An effective and acceptable procedure for reducing disruptive behavior in young children in a group setting. Journal o f Applied Behavior Analysis, 1976, 9, 55-64.

Schroeder, S. R., Peterson, C. R., Solomon, L. J., & Artley, J. J. EMG feedback and the contingent restraint of self-injurious behavior among the severely retarded: Two case ill- ustrations. Behavior Therapy, 1977, 8, 738-741.

Ulrich, R. E., & Azrin, N. H. Reflexive fighting in response to aversive stimulation. Journal OF Experimental Analysis of Behavior, 1962, 5, 511-520.

Webster, D. R., & Azrin, N. H. Required relaxation: A method of inhibiting agitative-disrup- rive behaving retardates. Behaviour Research and Therapy, 1973, 11, 67-78.

Wolf, M. M., Risley, T. R., & Mees, H. Application of operant conditioning procedures to the behavior problems of an autistic child. Behaviour Research and Therapy, 1964, /, 305-312.

Documents

Treatment of aggressive behavior: The effect of EMG response discrimination biofeedback training