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Stimulus Control
Jacky Maddi
Caldwell College
Presentation Overview
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What is a phobia?
How people react to phobias?
Types of phobias
Prevalence of phobias
Treatment options
Review of Article
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Stimulus Fading and Differential Reinforcement for
the Treatment of Needle Phobia in a Youth with
Autism
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Daniel B. Shabani and Wayne W. Fisher
 Journal of Applied Behavior Analysis, 2006
What is a phobia?
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Phobias are an exaggerated usually
inexplicable and illogical fear of a
particular object, class of objects, or
situation.
Defined as a medical condition in the
DSM – IV (300.29)
How do people react to phobias?
Common phobia symptoms and sensations include:
•Shortness of breath or smothering
sensation
•Palpitations, pounding heart, or
accelerated heart rate
•Chest pain or discomfort
•Trembling or shaking
•Feeling of choking
•Sweating
•Nausea or stomach distress
•Feeling unsteady, dizzy, lightheaded,
or faint
•Feelings of unreality or of being
detached from yourself
•Fear of losing control or going crazy
•Fear of dying
•Numbness or tingling sensations
•Hot or cold flashes
•Fear of fainting
The National Institute of Mental Health (NIMH)
http://www.nimh.nih.gov/health/publications/anxiety-disorders/completepublication.shtml#pub6
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The National Institute of Mental Health (NIMH)
estimates that 5-12% of Americans have phobias.
This is almost 6 million Americans. Approximately 79% of children have been estimated to have SP.
The mean age of onset depends on the type of
phobia.
Fears and phobias are common in young children.
Referral rates tend to increase in mid-to-late
childhood and early adolescence.
History
Behaviorally, phobias manifest as the
need to escape or avoid the feared
object or situation.
Phobias are twice as common in women
as men.
Similarly, children whose parents display a
higher rate of specific phobia have
higher rates themselves.
Causes
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Numerous theories about the etiology of
specific phobias have been offered among
them are:
Learning theories
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Classic conditioning: A previous neutral stimulus
has been paired with an aversive stimulus that
elicits a strong fear or emotional response.
Operant conditioning: Parents may inadvertently
reinforce the phobic behavior by providing the
child with positive or negative attention
surrounding the avoidant behavior.
Cognitive Models
 Cognitive models: Because learning
theories may not adequately explain the
development and persistence of
phobias, attention has been focused on
the role of cognition.
 Children with anxiety disorders are
more likely to display distorted and
maladaptive thoughts.
Types of Phobias
1)
2)
3)
4)
5)
Animal phobias.
Natural environment phobias.
Situational phobias.
Blood-Injection-Injury phobia.
Other phobias. This includes all phobias that
don’t fall into one of the first four categories.
Examples include fear of choking, fear of illness,
fear of injury, fear of death, and fear of clowns
Animal Type
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The fear of spiders
(arachnophobia)
and the fear of snakes
(ophidiophobia)
Natural Environment Type
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Like the fear of
heights (acrophia)
and the fear of
lightning and
thunderstorms
(astraphobia)
Situational type
Like the fear of small confined spaces
(claustrophbia)
Or being "afraid of the dark,"
(nyctophobia).
OTHER
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The fear of the
number 13
(triskaidekaphobia),
The fear of clowns
(coulrophobia).
Focus of the Article
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The fear of medical
procedures including
needles and injections
Belonephobia: fear of needles
Aichmophobia: fear of pointed
objects
Algophobia:fear of pain
Trypanophobia:fear of injections
Diabetes
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There are 20.8 million children and
adults in the United States, or 7% of
the population, who have diabetes.
http://www.diabetes.org/diabetesstatistics.jsp - American Diabetes
Association
Stimulus Fading and Differential Reinforcement for the
Treatment of Needle Phobia in a Youth with Autism
Introduction
The purpose of the study was to treat
needle phobia with behavior techniques,
stimulus fading plus a DRO,
to reduce the child’s fear and to facilitate
the treatment of a medical condition.
Method
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Participant – Oliver and 18 year old boy diagnosed
with autism, mental retardation, and Type 2 diabetes.
He attended an out patient clinic 4 days per week
for treatment of non-compliance related to his
diabetes.
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He had not allowed medical professionals to draw blood
for 2 yrs.
He had no vocal speech and communicated only through
a few manual signs.
Method
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Setting – Sessions were conducted in a
treatment room (3m X 3m) containing a
table, chairs, and assorted reinforcers
such as cookies.
Generalization sessions were conducted
in the nurses office.
Dependent Variable
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The percentage of successful trials
which was defined as:
Oliver not moving his hand more than
3cm during a 10s trial.
IOA
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IOA was collected trial by trial during
27% of sessions and was always 100%
Preference Assessment
DeLeon & Iwata, 1996
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Prior to each
session, potential
edible reinforcers
were identified using
a multiple-stimuluswithout replacement
preference
assessment.
Design
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An ABAB reversal design was used. The
horizontal distance of the lancet to the
tip of Oliver’s finger varied upon
condition.
The vertical distance stayed the same
(8-10 cm).
The starting distance was 61 cm away.
Baseline
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Oliver was given a verbal and gentle
physical prompt to place his hand on
the posterboard. The therapist moved
the lancet toward his finger.
Immediately upon the therapist’s
movement, Oliver pulled his hand away.
The trial was terminated. Baseline trials
lasted 10s or less.
Stimulus Fading plus DRO
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Fading Step 1 – Oliver had his hand on the within the
outline on posterboard
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The lancet was horizontally positioned 61 cm from
Oliver’s index finger
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If he stayed within the outline for 10s he was given a
food item that he had chosen earlier.
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If he moved more than 3cm – the trial was
immediately terminated, all the materials were
removed and the experimenter turned away for 10s.
Stimulus Fading plus DRO
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Fading from each step was done after 2-3
consecutive sessions at 100%
Step F2-F7 the distances were 46, 31, 15, 8,
5, 1cm.
Step F8 10 trials with the lancet 1cm above
his index finger and an attempt to draw blood
on the 11th trial
Step F9 attempts to draw blood were
intermittent
Results
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During baseline Oliver pulled his hand
away EVERY time they tried to draw
blood.
All attempts to draw blood in Step F9
were successful. Drawing blood in the
nurses station was also successful.
Graph
Generalization and Maintenance
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A two month follow-up was conducted
in which blood draw was successful.
Oliver’s mother reported that she was
able to draw blood and measure
glucose levels on a daily basis with no
problems.
Limitations
1.) An analysis of each component was
not conducted to determine the
independent contributions of the
stimulus fading and the DRO
components.
Another limitation
The level of distress was not measured during each trial
Crying, whimpering and negative vocalizations appeared
during baseline and at the beginning of treatment but
were not there at the end or during follow-up.
A chart like this I used with typical patients to rate their
levels of anxiety.
 Low Anxiety1–19
 Medium Low Anxiety20–39
 Medium Anxiety40–59
 Medium High Anxiety60–79
 High Anxiety80–100
Programming for Generalization
based on the 9 categories of generalization
Stokes & Baer (1977)
1.) Train & Hope
There was no information on the number of therapists
used, the setting was somewhat limited, and the glucose
testing machine was always the same.
2.) Sequential Modification
Behavior change did take place in the therapy sessions and it was
generalized to the nurses station and to the home environment. It
might be useful to have trained in other locations such as a
restaurant or in the car.
Programming for Generalization
based on the 9 categories of generalization
Stokes & Baer (1977)
3.) Introduce to naturally maintaining contingencies.
I can’t think of any natural contingencies that would maintain glucose
monitoring. However, I would have liked Oliver to be able to test his blood
independently.
4.) Train sufficient exemplars
Not done. There was no mention of how many therapists were involved, if the
blood taken in the nurses office was done by a nurse, was she wearing a
uniform, gloves, mask? The equipment never changed. What if the model of
the glucose machine became obsolete?
5.) Train loosely
Nope. Could have changes the poster-board, or whether Oliver was
sitting or standing.
Programming for Generalization
based on the 9 categories of generalization
Stokes & Baer (1977)
6.) Use indiscriminable contingencies
Although I was pleased to see a preference assessment was conducted
there was no mention as to the amount of edible reinforcer was given,
a delay in giving the reinforcer was never mentioned, nor was it
mentioned if Oliver ever became satiated during the phases that
contained 20 trials.
7.) Program common stimuli
Mom or the nurse could have come into the therapy setting before Oliver
completed the study. Therapists could have continued to work with
Oliver at home before mom took over.
Programming for Generalization
based on the 9 categories of generalization
Stokes & Baer (1977)
8.) Mediate Generalization
Due to the fact that Oliver was non-verbal teaching him to self-instruct
may not be possible. Creating a activity schedule of the glucose
monitoring procedure could be beneficial in helping Oliver to
understand the process in other settings.
9.)Teaching generalization as a behavior
Reinforcement in the form of edibles or activity could be given to Oliver if
he allowed mom to test his blood sugar in another room in the house,
or an outside location.
References
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Shabani, D.B., Fisher, W.W. (2006). Stimulus
fading and differential reinforcement for the
treatment of needle phobia in a youth with
autism. Journal of applied behavior analysis,
39, 449-452.