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TREATMENT OF AGGRESSION WITH BEHAVIORAL PROGRAMMING THAT INCLUDES SUPPLEMENTARY SKIN-SHOCK

Matthew L. Israel, Nathan A. Blenkush, Robert E. von Heyn, and Patricia M. Rivera

Judge Rotenberg Educational Center
Canton, MA USA 

Abstract

Behavioral treatment of aggression with contingent skin shock (CSS) has been investigated in relatively few studies and never with cognitively typical individuals. We evaluated CSS during a 3-year period with 65 participants, half to two-thirds of whom functioned at normal or near-normal cognitive levels. Sixty five individual charts, arranged in a multiple baseline across participants display, reveal clearly the effectiveness of the treatment. When end-of-baseline data was compared with end-of-treatment data, CSS, as a supplement to positive programming, showed effectiveness (defined as a 90% or greater reduction from baseline) with 100% of the participants. This compares favorably with Positive Behavior Support procedures, which, according to the 1999 treatment outcome review by Carr at al., achieved that effectiveness standard with only 55.5% of the cases. (Carr et al., 1999). Higher functioning participants showed 2-7 times more reduction than did lower functioning participants. Psychotropic medications were reduced by 98%, emergency takedown restraints were reduced by 100% and aggression-caused staff injuries by 96%. Thirty-five percent of participants no longer required CSS and some returned to a normal living pattern.

Key words: aggression, contingent shock, skin-shock, punishment

Treatment of Aggression with Behavioral Programming that Includes Supplemental Skin-Shock

Individuals who exhibit high frequency and/or high intensity aggressive behaviors are often treated with psychotropic medication and behavioral procedures. Unfortunately, psychotropic drugs have proven ineffective in treating the aggression of many individuals, including all of the participants in the present study. They also sometimes produce unfortunate side effects such as sedation, severe weight gain, Neuroleptic Malignant Syndrome, etc.

The behavioral procedures employed in current clinical practice to treat aggression are usually limited to “positive-only” procedures such as the manipulation of positive reinforcers, the arrangement of antecedents and setting events, provision of educational procedures, and the use of decelerating procedures other than physical aversives. If such procedures prove to be insufficiently effective, the individual is likely to continue to receive high doses of psychotropic medication, may be subjected to substantial amounts of restraint or isolation, and/or may be transferred to a highly restrictive environment (Foxx, 2003).

Contingent skin-shock (CSS), when used as a supplement to other behavioral procedures, has proven effective in treating various problem behaviors that were otherwise intractable. Most of the CSS treatment studies that have been published since 1965 have involved self-injurious behaviors (e.g., Salvy, Mulick, Butter, Bartlett, & Linscheid, 2004; Linscheid & Reichenbach, 2002; Duker & Seys, 1996; and Mudford, Boundy, & Murray, 1995). Other behaviors treated have included  (ordered according to the frequency with which the topic has been reported) aggression (e.g., Foxx, McMorrow, Bittle, & Bechtel, 1986); ruminating and/or vomiting (e.g., Wright, Brown, & Andrews, 1978; Cunningham & Linscheid, 1976; Toister, Condron, Worley, & Arthur, 1975; Browning, 1971; Kohlenberg, 1970), auditory hallucinations (Turner, Hersen, & Bellack, 1977; Alford & Turner, 1976; Bucher & Fabricatore, 1970), destruction (e.g., Foxx, McMorrow, Bittle, & Bechtel, 1986; Bucher & King, 1971; Birnbrauer, 1968) screaming (Lebow, Gelfand, & Dobson, 1970; Hamilton & Standahl, 1969), obsessive behaviors (Anderson & Alpert, 1974); wrong answers (Kircher, Pear, & Martin, 1971; Birnbrauer, 1968), self-induced seizures (Wright, 1973), stereotypic rocking (Baumeister & Forehand, 1972), and compliance with a direction to approach (Lovaas, Schaeffer, & Simmons, 1965).

With respect to the use of CSS to treat aggression, we found nine original published studies but none in the last 13 years. The topographies treated included aggressive biting (Foxx, Zukotynski, & Williams, 1994), hair-pulling and aggressive/destructive episodes (Foxx, Bittle, & Faw, 1989), pinching, kicking, hitting, and hair-pulling (Foxx, McMorrow, Bittle & Bechtel, 1986), assaults toward others (Ball, Sibbach, Jones, Steele, & Frazier, 1975), biting, kicking, and choking (Brandsma & Stein, 1973), physically striking another person, (Browning, 1971), hitting, kicking, biting, spitting, and verbal threats to aggress (Ludwig, Marx, Hill, & Browning, 1969), biting, (Birnbrauer, 1968) and aggression toward a brother (Risley 1968).

The CSS literature has limitations. First, most papers report CSS use with only one or relatively few individuals. The largest study was by Duker and Seys (1996) who reported CSS use with 12 participants.

Second, a variety of shock delivery systems with varying shock intensity and durations have been used. For example, within the past 21 years, shock delivery systems have included the HSP 3012 (Duker & Seys, 1996), Therapeutic Shock Device (TSD) (Mudford, Boundy & Murray, 1995), Hot Shot Power Mite (Williams, Kirkpatrick-Sanchez, & Iwata, 1993), Self-injurious Behavior Inhibiting System (SIBIS) (Linscheid, Iwata, Ricketts, Williams, & Griffen, 1990), and Tritronics A1-70 (Foxx, McMorrow, Bittle, & Bechtel, 1986). The differing devices and often incomplete descriptions of their parameters make it difficult to compare the effect of CSS treatment across studies or individuals.

Third, most CSS studies have been with participants who functioned at a relatively low cognitive level and who had diagnoses such as severe mental retardation (MR) and related disabilities. Few studies have involved participants with normal or near-normal cognitive levels who had diagnoses such as conduct disorder, bipolar disorder, oppositional defiant disorder, and impulse control disorder.

In this paper we report data and procedures that address these issues. We treated aggression in 65 individuals with widely differing levels of cognitive functioning for periods of up to three years, using positive behavioral procedures supplemented with CSS. We report the immediate effects of CSS insertion on behavior frequency, the overall reductive effect of CSS, and its effect on ongoing accelerations or decelerations. We compare the reductive effect of CSS with the reductive effect of Positive Behavior Support in treating aggression. We describe the differential effect of CSS treatment on participants with differing levels of cognitive functioning. And we describe the effect of CSS treatment of aggression on the need for psychotropic medication, on the need for emergency takedown restraint, and on aggression-caused staff injuries.

Method

Participants

A total of 65 (44 male and 21 female) residents, who were enrolled at the Judge Rotenberg Center (JRC) in Canton, MA participated in the study. The median age was 17 (range 9-36). Prior to enrolling in JRC, the participants had attended a median of 4 (range 0-42) special needs day, residential, psychiatric or correctional programs and had been prescribed, at various points in their history, a median of 6 (range 1-21) different psychotropic medications. Although treatment histories varied, all participants in this study had been rejected by, unsuccessfully treated in, or expelled by other settings that had used a combination of positive-only behavioral interventions and psychotropic medications.                                                

Demographic information for the participants is presented in Table 1. Note that the total of Other Diagnoses (89) exceeds the number of participants (65) because many participants had multiple diagnoses. Forty six percent did not have an MR diagnosis.

Table 1

Participant demographic information including frequency count of all assigned diagnoses (N=65)

The participants were all of the JRC residents, without exception, for whom CSS had been added to their programs at some point during the 3-year period from June 1, 2003 to May 31, 2006 and whose enrollment had not been significantly interrupted by absences. During this period a total of 65 residents met this criterion. Another 7 additional residents had CSS added to their programs during this period; however, their data were excluded from this study because of long absences from the program due to medical needs or other circumstances.

CSS was not considered for each participant until a variety of positive-only procedures had been tried at JRC and had been found or judged to be insufficiently effective in light of the clinical needs of each participant. The median number of weeks during which positive-only procedures alone were tried, prior to the introduction of CSS, was 37 (range 2-108). In a few cases, where the aggressive behavior was judged to be so extreme or problematic that even a single occurrence could be extremely dangerous, CSS was started shortly after the participant was admitted to JRC.

Psychotropic medication

Fifty-two of the 65 participants were receiving a median of 2 (range 1-6) psychotropic medications when they enrolled at JRC. Under the direction of a consulting psychiatrist, these medications were gradually reduced over a median of 5 (range 0-42) months. Most participants were weaned from psychotropic medication during the baseline phase. In a few cases the weaning extended into the treatment phase.

Safeguards

The following safeguards were in effect prior to the use of CSS. (a) The parent/guardian gave informed written consent to the use of CSS. (b) If the participant was of school age, CSS was placed in his or her Individual Education Plan. (c) A doctoral level clinician, with training in behavioral psychology, headed the participant’s treatment team and composed a treatment plan that included the option to employ CSS. (d) A physician and, where appropriate, a neurologist and/or cardiologist, certified the absence of medical contraindications to the use of CSS for each participant. (e) A psychiatrist certified the absence of psychiatric contraindications to the use of CSS for each participant who had a mental illness diagnosis. (f) An internal peer review committee reviewed the plan and deemed it appropriate. (g) A human rights committee composed of JRC parents, as well as community members unaffiliated with JRC, approved the plan. (h) A Massachusetts Probate Court judge authorized the treatment plan through a "substituted judgment" petition in an individual court hearing in which the participant was represented by his or her own court-appointed attorney. (i) The court-appointed attorney retained his or her own psychologist to provide advice concerning the proposed treatment.

Additional safeguards were in effect after the treatment plan went into effect. Reports on the participant’s treatment status were submitted to the Probate Court every 3 months and the judge held a formal review each year. In all cases in which CSS was used for 3 or more years, a special committee composed of JRC staff and consultants, including two independent clinicians unaffiliated with JRC, reviewed the treatment and its results to determine if it should continue.

Setting                                                                                                                                                            

All participants lived in apartments or homes operated and staffed by JRC and were transported to and from JRC’s day program where they received treatment, education, and vocational instruction and opportunities. During the first 4 months of the 3-year period reported here, participants attended the day program 5 days per week. During the remaining 32 months of the period, participants attended the day program 7 days per week. The same treatment procedures were in place and carried out consistently in the school building, in the residence, on field trips, and during transportation to and from school.

The participants’ programs in both day and residential settings were monitored directly by on-scene supervisors, as well as remotely by supervisors who watched live and recorded video and audio, on a sampling or continuous 24/7 basis. Video cameras and microphones were mounted in all appropriate locations of the school and residences. This equipment allowed the supervisors to monitor from a central office, in real time over the internet, all activities in the participants’ classrooms and residences.

Behavior categories and topographies

A supervising clinician, with a caseload of 15 to 20, oversaw each participant’s program with the assistance of other members of the treatment team, such as the teacher, residence supervisor, and a case manager. The behavior category treated was termed “aggression,” meaning any behavior that inflicted harm on other persons. Because there are an unlimited number of topographies that a participant could use to inflict harm on others, and because new topographies could emerge abruptly, each participant’s clinician identified the topographies that were currently in the participant’s repertoire and was authorized, in the court-approved treatment plan, to identify and add other topographies to the treatment plan as soon as they were displayed.

Examples of topographies within the aggression category included the following: hit others, bite others, kick others, throw objects at others, head butt others, choke others, and pull hair of others. The topographies treated included not only the ultimate aggressive behaviors themselves, but also antecedent behaviors, attempts and threats to execute the behavior, shaped-down (vestigial) versions that were displayed during the deceleration of the behavior, as well as initial and intermediate members of the chain that included the ultimate aggressive action.

For all participants, aggression was only one of several behavior categories that were treated with CSS at the same time. The other categories that were treated depended on the participant’s treatment plan and could include health dangerous (self-injurious), destructive (e.g., breaking windows, desks, computers), noncompliant (e.g., refusal to follow a request), and major disruptive (e.g. swearing, yelling, disrobing in public, etc.), behaviors. Data for the treatment of these other behavior categories are not included in this report.

Data collection

Frequency data was collected by direct care staff 24 hours per day, 7 days per week. Each aggressive topography was tallied as it occurred, using recording sheets that were segmented by hour and that accompanied the participants in all activities. Hand counters were used to count high frequency behaviors. Aggressive behavior sometimes occurred in episodes in which several aggressive actions occurred within a short period of time. In these cases, the staff member administered one application of skin-shock to consequate the entire episode, but tallied each individual aggressive behavior. The total number of aggressive behaviors exhibited each day was entered in a database and displayed on daily, weekly, monthly, or yearly software charts that were updated daily and made available to clinicians, teachers, and parents through a computer network. Total skin-shock applications were recorded separately and totaled across all treated behaviors, but were not separated by behavior categories such as aggression.

To evaluate the effects of CSS treatment of aggression on participants of differing functioning levels we classified students by functioning level and compared the reductive effect of the treatment on the two groups. To obtain information about psychotropic medication use, emergency takedown restraints, and aggression-caused staff injuries we reviewed the participants’ records as well as records of staff injuries.

Materials

CSS was administered by means of a skin-shock device called the Graduated Electronic Decelerator (GED). GEDs of two strengths were used—the GED-1 and GED-4. The GED-1 produced an average current of 15 mA RMS and an average voltage of 60 V RMS when applied to a resistor of 4 kΩ (typical skin resistance for the GED-1). The electrical stimulus was a preset, 2 s train of direct current square waves with a duty cycle of 25% and a pulse repetition frequency of 80 pulses per second. The GED-4 produced an average current of 41 mA RMS and an average voltage of 66 V RMS when applied to a resistor of 1.6 kΩ (typical skin resistance for the GED-4). The other parameters of the GED-4 were identical to those of the GED-1.

Each GED system was comprised of a remote control transmitter, a shock generator (the GED device itself), a battery and an electrode. The transmitter, a SECO-LARM (model SK-919TD2A) two-channel RF transmitter, operated at 315 MHz and transmitted a uniquely coded signal to the receiver which was worn by the participant. The transmitter was housed in a lexan box (104 mm x 76 mm x 38mm) with the participant’s name and photo on the outside.

The shock generator consisted of a receiver (SECO-LARM model SK-910) set to the same code as the transmitter, a shock controller circuit board that created the shock stimulus, and a stimulation-indication beeper (Mallory piezoelectric ceramic buzzer model PLD-27A 35W). The shock generator was housed in a lexan box (140 mm x 89 mm x 38 mm) and the unit weighed 269 g.

A 12 V rechargeable nickel metal hydride battery pack (Panasonic P/N HHR-AAB 2000 mAh) provided power to the shock generator and was housed in a lexan box with the same dimensions as those of the shock generator. The battery unit weighed 397 g. The battery was attached by Velcro to the shock generator and connected to it electrically by a short cable (Hirose Electric Co., Ltd., Part # H0063-ND). The battery and shock generator were both carried in a back pack or fanny pack worn by the participant. A cable (Hirose Electric Co., Ltd., Part # H0063-ND) connected the shock generator to the electrode. Each electrode was attached to one of several pre-approved locations, typically the arms, legs, or torso. The electrode and connecting cable were hidden by the participant’s clothing.

The electrodes employed during the 3-year period were of two types: (1) a “concentric” electrode which consisted of a stainless steel button (diameter 9.5 mm, thickness 3.25 mm) surrounded by a stainless steel ring (outer diameter 21.5 mm, inner diameter 16.5 mm, thickness 3.25 mm) with 2.35 mm between the outer edge of the button and the inner edge of the ring; or (2) a “distanced” electrode consisted of two stainless steel buttons (diameter 9.5 mm, thickness 3.25mm) mounted up to 15.24 cm apart on flexible nonconductive material. During the 3-year period covered in this report, the vast majority of the participants wore distanced electrodes.

Each participant wore from one to five GED sets (each consisting of battery, shock generator, and associated electrode), depending on the decision of the participant’s clinician. Each remote control unit sent a signal to only one particular GED shock generator and that shock generator was connected to one electrode on the participant’s body. When a participant wore more than one GED set, the therapist possessed a separate remote control for each set. In these cases, on any given application the participant did not know which electrode would deliver the skin-shock (i.e., which remote control device the staff member would employ).

Procedure

There were two phases, baseline followed by treatment.

Baseline (Positive Programming). Upon admission, functional assessments were completed for each participant. These suggested functions that were varied among individuals and were sometimes multiple and unknown.

To take account of the various possible functions, all environments and staff procedures were designed so that regardless of what event or events might function as a reinforcer on any given instance of the behavior, inadvertent or deliberate reinforcement of undesired behaviors would be avoided or minimized. In particular, systems were set up, and staff were trained, to insure that (1) any inadvertent reinforcement from positive or negative attention would be minimized or avoided whenever problem behaviors occurred; (2) any escape from demands that inevitably had to occur after a problem behavior was displayed, would also be minimized or avoided; and (3) desired tangible items or activities would never be arranged or allowed as the immediate consequence of a problem behavior. All participants were taught how to gain attention, escape from work, and obtain desired items or activities through appropriate and easily executed behaviors.

The participant’s clinician reviewed daily behavior frequencies and frequency trends over time. As the clinicians prescribed and adjusted combinations of antecedent, reinforcement, extinction, response cost, and other procedures, they were able to see the effects of these changes in the charted data and make compensating adjustments when required. This amounted to an ongoing, in vivo functional analysis in the natural environment.

During the baseline phase, a variety of positive programming procedures were employed to decrease the aggressive behavior and to teach alternative desired behaviors. Each participant had DRO/DRA contracts in which, if the participant avoided displaying the problem behaviors during a certain period of time or activity, and also displayed desired behaviors in their place, reinforcers would be earned. Typically, each participant had multiple overlapping contracts covering different stimulus situations and periods (transport, overnight, less-than-a-day length, multiple-day length, etc.). The length of the contracts was gradually lengthened whenever possible. When a participant passed a contract, he/she was given points, tokens, or immediate access to desired items or activities. By passing a sufficient number of contracts, students could advance to higher level classrooms and residences with more privileges, gain more independence, and/or earn a part-time or full-time paid job inside or outside JRC.

Participants also received points, tokens, and other reinforcers on an intermittent basis throughout the day (essentially on an intermittent, momentary DRA schedule) provided they were “on contract” and engaging in appropriate behavior at the time the reinforcer was delivered.

Points, tokens, and direct access to reinforcers could also be earned by learning new academic, self-care and vocational skills and by responding appropriately to programmed stimuli, sometimes designed to represent stimuli that trigger problem behaviors, presented at various points during the day.

Points and tokens could be turned in for access to one or more of the following: money (participants could earn as much as $30 per week); field trips; the Reward Corner of the classroom;  the Big Reward Store, which was an arcade-type room with pool table, pinball machines, video games etc.; the internet; the Contract Store, which was a retail “store” with a variety of items for sale; items in the Classroom Reward Box; weekly field day activity, including barbecue and other desired activities; extra phone calls to parents and friends; opportunity to watch TV, play video games, or listen to music using entertainment consoles in the participants’ bedrooms and living rooms; etc.

Other procedures included functional communication training, training in social skills, self-instruction in academic skills using personal computers as teaching machines (Skinner, 1958), and vocational training. Higher functioning participants were given behavioral counseling, self-management training, a course in behavioral psychology presenting a simplified version of the concepts presented in Skinner’s “Science and Human Behavior” (Skinner, 1953), and weekly behavioral chart shares with other participants/students.

Every item or activity that the participants might enjoy was used as a contingent reward to encourage desired behavior. Undesired behavior resulted in money or point fines and/or a loss of privileges previously earned. Extremely dangerous behaviors were contained using emergency restraint and protective equipment. In some cases, mechanical restraint was employed to insure the participant’s safety.

Treatment (Add Skin-Shock). In this phase, all of the positive procedures employed during the baseline phase continued to be used and adjusted by the clinicians; however, all topographies listed under the aggression category were now also “consequated” with a single GED application as soon after they occurred as possible. The normal procedure for administering a GED application required the staff member to enlist a second staff member to insure that (a) the person about to administer the GED had selected the correct recording sheet for the participant, (b) the topography that had just occurred (or which was still occurring) had been pre-identified on that recording sheet as being a treatment target, (c) the consequence (GED) was the correct consequence for that topography, and (d) the person administering had selected the correct remote control for the participant. These requirements introduced a slight delay in the administration of the consequence; however, the gains in insuring proper execution of the procedure were judged to be worth the slight delay involved.

Some participants wore more than one GED, and up to a maximum of five GEDs, if it was necessary to consequate attempts by the participant to remove the equipment or interfere with the application, and/or where the participant would otherwise defeat much of the effect of the skin-shock by tensing the muscles in the affected area prior to the application. Electrodes were rotated to different skin locations at the end of each hour and after a skin-shock was applied.

In certain cases, when equipment failure or other factors prevented the administration of the skin-shock, a verbal reprimand was substituted.

During the treatment phase, each time the student displayed an aggressive behavior, the staff member who administered the GED recorded the apparently-triggering stimulus as well as other setting information on the participant’s daily recording sheet. This information was used by the clinician in his or her ongoing in vivo functional analysis of the aggressive behavior.

All 65 participants were included in the Treatment phase. A total of 56 were started on skin-shock using the GED-1, and 9 were started using the GED-4. The decision as to which to start with was made by the clinician, and depended on factors such as the seriousness and severity of the problem behavior, the participant’s previous history, and the need to maximize the likelihood of rapid and effective treatment.

In two cases, the GED-1 was employed first and the participant was later switched to the GED-4 either because the GED-1 was judged to be insufficiently effective in treating the aggression, or because it was insufficiently effective in treating one or more of the other behavior categories that were being treated concurrently.

Results

Chart display.

Individual charts showing weekly totals for the participants’ aggressive behaviors are presented in Figure 1. There is one chart for each participant and each participant is identified as Participant 1, Participant 2, etc. The charts are multiply/divide charts in which a relative change (e.g., a doubling, tripling, or halving) occupies a constant up-down distance anywhere on the chart. Each vertical line represents 1 week and heavy vertical lines represent every 5th week. A dashed vertical phase line indicates the week during which the participant’s treatment program was supplemented with the GED-1 or GED-4. These charts are very similar, but not identical¹, to the weekly version of the Standard Celeration Chart (Pennypacker, Guiterrez and Lindsley, 2003) that is employed in Precision Teaching (Lindsley, 1990).

The data point for each “skin-shock insertion-week”—i.e., the week within which the GED procedure was introduced—has been omitted because the total for that week, which was based on one or more days from both the baseline and treatment phases, belonged in neither phase. The data for those weeks are provided in the Appendix. Similarly, in the two cases in which a participant was changed from the GED-1 to the GED-4 during the treatment phase, the data point for the week during which the change was made has been omitted because the total for that week, which was based on one or more GED-1 days as well as one or more GED-4 days, belonged in neither condition. The data for those weeks also, are provided in the Appendix.

The charts are arranged vertically in a single column according to the date on which the GED was added to the participant’s program. As a result, the charts are displayed in what amounts to a multiple-baseline-across-participants display with the intervention line (that shows the introduction of the GED) jogging to the right after each chart to show the passage of time before the next participant started on the GED.

Casual inspection of these charts shows that the supplemental use of the GED was effective in decelerating aggression in almost every single case. This is particularly true when one takes into account the fact that on these charts (when displayed at 100% size on a computer screen) a vertical distance of approximately 6.35 mm (1/4 in) upwards or downwards, represents a doubling or halving, respectively, of the frequency.

Figure 1.  The weekly frequency of aggressive behaviors for each participant between June 1^st, 2003 and May 30, 2006.

Trends during baseline

Table 2 summarizes the trends seen during the baseline (positive programming) phase. In 42 participants (67% of the 63 cases where there was sufficient information to characterize the trend), the frequency was either increasing (accelerating) or flat when CSS was introduced. In the remaining 21 cases, even though the behavior was decreasing in frequency (decelerating), CSS was introduced because the behavior was too dangerous to be allowed to occur at the frequency it was showing.

Table 2

Trends of aggressive behavior during baseline

Decelerative effect of CSS on aggressive behaviors

To analyze CSS’s decelerative effect, we examined: (1) the initial effect on frequency associated with CSS introduction; (2) the overall chart patterns found during the treatment phase; (3) the overall decelerative effect seen when all baseline data is compared with all treatment data; and (4) the changes in trends from baseline to treatment.

Initial effect on frequency. In almost every chart in Figure 1, the GED is shown to produce two separable effects. It causes an immediate decrease in frequency (jump down) right after it is introduced, and this is followed by some other trend over the succeeding weeks.² We chose to measure these immediate jump downs by plotting the trend (celeration) lines for both the baseline and treatment data, and measuring the vertical distance between the end of the baseline celeration line and the beginning of the treatment celeration line. If there was more than one trend during baseline or treatment, we used the last trend in the baseline data and the initial trend in the treatment data.

Figure 2 shows how this was done, for example, in the case of participant 13. The size of the jump down at the time of CSS introduction is the same up/down distance as the distance between 1 and 85 on the vertical scale of the multiply/divide chart in Figure 2. Therefore the jump would be characterized as a “÷ 85” (read “divide 85”) jump down which means that the frequency divided by a factor of 85. Table 3 shows the jump down that occurred immediately after CSS insertion for each participant. It shows that median jump down was ÷26, meaning that the weekly frequency made an immediate decrease by a factor of 26.

Figure 2. Sample weekly chart showing calculation of frequency jump down

Table 3

Frequency jump downs occurring immediately after CSS insertion (organized by magnitude)