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Evaluating treatment efficacy for adults: Assessment of stuttering disability
EVALUATING TREATMENT EFFICACY FOR ADULTS: ASSESSMENT OF STUTTERING DISABILITY
The propod strategy for evaluating the efficacy of’ treatment for adult\ ti ho stutter involves repeated ahse\smcnt\ ofst~ttcring and speech naturalness i’-om conversation ample\ recorded in and away from the clinic. This stl-:lteg)’ conceptualircs chronic stuttering among adult\ as ;I di\or-dcr that is hc\t vicwd and measured at three level\: impairment. disability. and handicap. .A common goal of current treatments for adult stuttering i\ the reduction or climinatlon of the disability of stuttering. Therctbre. the evaluation of treatment efi’icac~ is logically and most directly related to mea\urc\ of stuttering disability. Both basic and optional mca\ures of the diahilith, of stuttering arc propod and discussed.
INTRODUCTION In 1973 a review tering
is
Andrews, about
of behavior
a comparatively 1973.
p. 408).
the reliability
can be found
1973: mcnt.
(Coyle it was
quency tering
1975). widely
counts
There
counts
of these until
events
are now
1981
findings
measures
of stuttering
been apparent
; MacDonald that
sufficiently
(Kully
and
concerns for
and Martin.
on event-by-cvcnt
the effect\
data indicating
be misplaced
“\tuf-
on the loci ofstutteriny
recently, were
that
(Ingham
increasing
it has
low agreement
for quantifying
may
however.
example,
1979: Curlee.
stated
to measure”
of perceptual For
believed,
of stuttering
measure
clients.
frequency
that time.
evidence
In spite
and stuttering
disorder
and validity
and Mallard.
Young.
as 21primary
Since
in the literature.
some time that listeners events
therapy
simple
agrecmcnt high for
of treatment that
and
such Bohcrg.
ago-eeon fretheir with
confidence Ic)XX),
USC \tutin and
320
R. F. CURLEE
subsequent efforts to develop procedures that yield measures of satisfactory reliability have achieved only modest success to date (Cordes et al., 1992). It should be noted also that persuasive arguments have been advanced in recent years that challenge the value of listener judgments of stuttering even if those judgments were reliable. Perkins (1990) claims, for example, that a speaker’s subjective experience of the loss of control of the speech production process is the only valid indicator of the occurrence of stuttering events. Others, such as Adams and Runyan (IYSI), Freeman (l984), and Smith (l990), have argued that the events that listeners perceive as stuttering events are only a subset of the abnormal speech production events that characterize the speech of those who stutter. Such arguments have selected neuropsychological and/or neurophysiological variables, rather disruptions in speech, as the most appropriate level at which to study and describe stuttering. Stuttering has been studied at various levels of observation, from central nervous system activity to perceptions of the acoustic product of the speech production process. All levels have provided useful information, and it is not yet clear which level(s) will be most valuable to our understanding of the nature of stuttering and of how best to manage it. Different levels of observation rely on different definitions and different measures of stuttering phenomena. A useful perspective for conceptualizing and evaluating the clinical management of a chronic, behavioral disorder, which Prins (1991) applied to stuttering, is that of the World Health Organization (WHO). This model views disorders of stuttering as having three levels: I. An impairment, which would include all of the neuropsychological and neurophysiological events that immediately precede and accompany the audible and visible events of stuttering. 2. A disahili~y, which would comprise the audible and visible events that are the behavioral manifestations of stuttering. 3. A handicap, which would consist of the disadvantages that result from reactions to the audible and visible events of a person’s stuttering and that would include those of the person who stutters. This view of stuttering appears to be particularly useful for differentiating the goals of different clinical management approaches and for organizing the different measures of treatment efficacy that are pertinent to those goals. There is much more information about the speech disabilities of those who stutter than there is about the nature of their speech production disruptions or about the kinds of handicaps that may result. Indeed, the nature of the disruptions in the planning and execution of speech
ASSESSMENT
that
OF
results
in the audible
is not well-understood. of those often
who
result
handicaps 1992).
have
ber
of other
assessing
handicaps
Stuttering
Inventory
Attitudes
(Watson.
arc needed of those
posed
from 1967).
was
stutter.
derived
from
Stuttering rarely
3.
A primary
Measures of
suited Thus,
this
stuttering
current
article
of reliable
signs
of stuttering
uating The
situations
by Costello stuttering from
the clinic.
conversational several
years
even
these
few
and mcaand handito be pro-
and inferences: event
until
at other
childhood
it has
levels
of
into
adult
life
is to eliminate
OI
remissions.
procedures
events
and
that comprise
most are
are well
systematic
valid
based
focus are.
comparisons
best
who stutter.
measures
on the
of an adult
perceptual
acquainted
;I practical.
on a primary
therefore.
of adults
of treatment
the
that
who
and that
of stuttering
procedures
and time provide
with of such
appropriate
judg-
the clinical measures
way for eval-
of treatment.
assessment
and lngham adults’
from
events
that
are those observers
the efficacy proposed
10X4),
workers
strategy
behavioral
the efficacy
proposes
disability
of
stuttering.
treatment
for assessing
to
and control.
spontancou\
of the behavioral
ments across
of adult
et al.,
disubilitics.
of events
treatment
prove
scales for
of study.
as a behavioral
and visible
et
the Perception
from
assumptions
persis;ts
goal of current the audible
the disability goal
that
extended.
useful
stuttering
efficacy
prediction
well
Ingham.
and a num-
1 could
(Craig of
units
descriptions
better
behavior
decrease 4.
that
evidences
scales
treatment
less
of Communication
be apparent
the following
provide
I991
the impairments.
which
(Onslow
1980).
include
of observation.
and rate
et al..
perceptions
is best conceptualized
observation
(Gow
Inventory
of control
The
been demonstrated 2.
the
It should
levels
lo quantify
who
Stuttering
locus
and arc even
Potentially
stuttering
of employers’ 1991).
(Wood
reactions
them.
and personal/social
(Alphonse.
(Woolf,
that different
study
impairment.
that result 198X),
with
and articulatory
flow
measures
stuttering
and Calver.
sures
I.
ofa
assessment
examples
blood
interact
intervals
durations
physiological
indices
caps
systematic
disability
and emotional
vocational.
phonation
cerebral
be useful
the
littlc
of vowel
regional
of a stuttering
who
educational,
received
variability
events
the cognitive
as those
Nevertheless,
IYE),
(Craig
as well
in significant
al..
and
and visible
Likewise.
stutter,
understood.
121
DISAHII~I’I’Y
speech Samples partners.
posttreatment,
strategy (1984) samples
is consistent
and involves
that are recorded
should
involve
extend
from
with
repeated
different pretreatment
and be supplemented
that advocated assessments
both
of
in and away
speaking samples by reports
tasks
and
through of family
322
R. F.CURLEE
members and occasional covert samples. Prior to the initiation ment, the following measures should be obtained to document ture and severity of a stuttering disability.
BASIC MEASURES
OF STUTTERING
of treatthe na-
DISABILITY
These measures are considered to be necessary components of any assessment of stuttering. They will be sufficient, however, only if no stuttering events are observed in a speech sample and if the sample’s speech naturalness ratings fall within the range of those expected of nonstuttering speakers. It should also be noted that elevated scores on the S-24 scale could indicate the need to obtain recordings of additional speech samples. If, however, the S-24 score is not elevated, no stuttering events are observed in the speech samples assessed and speech naturalness ratings are comparable to those of nonstuttering speakers, there should be no need to obtain further quantification unless there is reason to report a severity rating derived from standardized procedures. The basic, obligatory measures needed to assess a stuttering disability include: 1. frequency of stuttering (in percentage of syllables [% SS] or percent words [% WS] stuttered); 2. ratings of speech naturalness; 3. administration of the S-24 Scale (Andrews and Cutler, 1974).
OPTIONAL SEVERITY MEASURES STUTTERING DISABILITY
OF
Some of these measures should be selected to supplement the basic measures listed above whenever a sample contains stuttering events or receives elevated speech naturalness ratings. The specific measures selected should be determined by the characteristics of clients’ speech and stuttering events. For example, if a client’s longest sound prolongation or tense pause was less than a second, efforts to quantify their typical duration would likely have little clinical significance. In contrast, careful assessments of the duration of long stuttering events may provide early indications during treatment that a client’s severity of stuttering is decreasing. Even if a sample is free of stuttering events but receives elevated speech naturalness ratings, such measures as speech rate may provide insight into the reasons for the elevated rating. Many times, all of these measures may be needed. Finally, it should also be noted that additional, supplementary measures may also be
ASSESSMENT
OF DISABlI,ITY
needed in order to better assess the idiosyncratic stuttering events and patterns of speech of some clients. For example, the eye contact of many stuttering clients during conversations is frequently inappropriate, such behavior may be targeted for change in therapy. If so. it would be important to devise optional measure(s) of eye contact during video recordings of a client’s speech samples. Optional measures that will be needed most often to further quantify the severity of a stuttering disability include: I. duration of both typical and longest stuttering events (in seconds and/or number of repeated units); 2. length of typical and longest stutter-free segments of speech (in syllables or words): 3. rate of speech in syllables (SPM) or words (WPM) per minute: 4. administration of a standardized scale such as the Stuttering Severity Index (Riley. 1974).
MEASUREMENT
PROCEDURES
Descriptions of the optional severity measures listed above can be found in a number of refercnccs tc.g., Costello and Ingham. 1984). all of these measures will be used to assess the speech Ordinarily. samples of adults who stutter that were recorded prior to treatment in order to quantify a client’s stuttering disability in adequate detail. Samples obtained at termination of treatment and final posttreatment samples would utilize only those measures needed to further quantify any remaining stuttering events or unnatural speech patterns. Several of these measure are also intended to provide more sensitive indicators of changes in stuttering. both increases and decreases, during the intervention process. which may not be readily apparent in frequency of stuttering measures. Such measures (e.g., rate of speech) may also provide additional insight into the reasons for a client receiving elevated speech naturalness ratings. In contrast. the basic measures of stuttering disability are intended to indicate whether or not someone has stuttered during a recorded sample and, if so, how much. In addition. speech naturalness ratings should provide evidence of a client’s use of any compensatory speaking behaviors in the sample that sound unnatural or that draw adverse attention from listeners. Finally, the S-24 Scale is intended to suggest communication interactions away from the clinic that warrant observation and assessment. Guidelines for obtaining and interpreting these measures will be summarized briefly in the paragraphs that follow. There are no standard procedures in current use for counting stut-
324
R.F.CURLEE
tering events that are widely accepted. For example, some clinicians restrict counts to specific disfluency topologies, others count any speech disfluency that is perceived as unusual, abnormal, or effortful as stuttering. The development and adoption of a standardized set of such procedures would likely reduce at least some of the variability in stuttering counts often reported among different clinics and clinicians. Cordes et al. (1992) found that listeners who are well acquainted with the clinical signs of stuttering and who evidence high intraobserver agreement are also likely to evidence higher interobserver agreement. Consequently, the assessment procedures that will be described are best conducted by individuals with a number of years experience working with stuttering adults and who also evidence self-agreement levels consistently in excess of 0.80 when counting stuttering events. The following guidelines, which could also be used with children who stutter, illustrate one way of counting stuttering events of adults. Count only dysfluencies that are perceived as stuttered events rather than all disfluencies. Each syllable or word should be counted as either stuttered or not stuttered and should be counted only once regardless of how it was disrupted. If sounds. syllables, words, or phrases are repeated as if to facilitate initiation of the following word, only the syllable or word that follows is counted as stuttered. Count the number of syllables or words stuttered twice. If these counts agree, use that number to calculate % SS or % WS. If they do not agree, count stuttering events again and use the median or modal count for calculations. These guidelines view stuttering events to be a perceptual “threshold phenomenon” (Martin and Haroldson, 1981) and all speech events perceived to be stuttered are counted, regardless of the type of disfluency involved. This approach differs from those that define stuttering as a group of specific behaviors, typically the kernel characteristics of stuttering that were proposed by Wingate (19641, and that count only specific types of disfluencies as stuttering events. Empirical comparisons of these two approaches have found “perceptual threshold” counts to result in similar (Curlee, 1981) or higher listener agreement (Martin and Haroldson, 1981). As was noted above, there are no standardized procedures for training judges to identify stuttering events reliably or for monitoring or for recalibrating such judges’ performance following training. Consequently, there is an urgent need to develop such training and monitoring procedures or to establish special facilities that would assess recorded speech samples much as medical laboratories now assess fluid and tissue samples. In the absence of such standardization, one way to increase the precision and reliability of measurements is to rely on the
ASSESSMENT
OF DISABILITY
325
central tendency of repeated measures as was proposed in the above guidelines. Ratings of speech naturalness should utilize the procedures described by Martin and colleagues (1984). Those portions of recorded speech samples that are assessed for frequency of stuttering events should also be rated in terms of speech naturalness every 30 set by at least three to five independent raters. The median rating of each segment should be used to determine both the median and range of all ratings during a sample and should be compared to the ratings obtained from nonstuttering speakers. It should be noted that speech naturalness ratings need to be obtained from a much larger number of nonstuttering speakers so that the resulting data base will likely encompass the range of fluent and nonfluent speakers in the nonstuttering population. Such data would also permit the reporting of stuttering adults’ speech naturalness ratings as standard z-scores, which would also facilitate comparison of a client’s ratings to those of the nonstuttering population. Administration of the S-24 Scale (Andrews and Cutler, 1974) is included as a basic measure because of the need to select extra-clinic communication settings that may be troublesome for adults who stutter. Thus, this scale is not used to evaluate clients’ attitudes about speaking but rather as an indicator of the types of speaking tasks and situations that may be causing a client current stuttering difficulties. Scale items that are scored “1” can be utilized to identify the type and number of extra-clinic samples that need to be obtained, especially during transfer and follow-up assessments, so that arising or persisting difficulties with stuttering can be monitored and evaluated appropriately.
SAMPLES Prior to the initiation of treatment, at least two in-clinic conversations should be videotaped, one face-to-face, the other via telephone. Each should include at least 500 words, or 7.50 syllables, of the client’s speech. Neither conversational partner should be familiar to the client, and each sample should include segments intended to be stressful. Oral reading samples should also be recorded if it is reported that this task poses special difficulties or is of special importance to the client. At least three samples of similar length should be recorded away from the clinic. One should involve a conversational partner who is familiar to the client and who will be able to continue as a conversational partner through posttreatment samples. Remaining samples should be selected from those reported to be especially difficult for the client or those that elicited “ 1” responses from the client on the S-24 Scale. Large
326
R. F. CURLEE
differences in frequency of stuttering across samples (e.g., >25%) may indicate the need for replicating or obtaining additional samples. If an intensive treatment schedule (e.g., >I5 hr weekly) is utilized to establish speech that is free of stuttering, initial sampling procedures should be repeated before beginning transfer training if the efficacy of transfer training is to be evaluated. If a less intensive treatment schedule is utilized, outside clinic samples with the familiar partner and of one problematic situation should be recorded on alternate weeks until the client is ready for transfer training. At that time, initial sampling procedures should be replicated if the effect of transfer training is to be assessed. During transfer training, samples of at least two extra-clinic conversations should be recorded regularly until treatment is terminated. Early in training, such samples should be recorded at least weekly and should include one with the familiar conversation partner until there is no stuttering and speech naturalness ratings are within normal limits (WNL) for four consecutive samples. Later, only monthly samples may need to be recorded so long as speech naturalness ratings remain WNL and no stuttering events are observed on any sample. Additional recordings would be used to sample those reported as troublesome by the client or those that are suspected as problematic based on monthly administrations of the S-24 Scale. With prior written permission of the client, monthly covert samples can be used to evaluate a client’s speech when he or she is presumed to be unaware of being assessed. Initial sampling procedures should be repeated at termination of transfer training and at 6-month and yearly intervals thereafter so long as contact with clients is maintained.
SUMMARY The strategy that has been proposed for evaluating treatment efficacy relies on assessments of a client’s stuttering disability from recorded speech samples obtained in different settings prior to and at regular intervals during and following treatment. It was argued that stuttering is, in essence, a behavioral event, that current treatment procedures focus on modifying or eliminating these behavioral events, and that the perceptual judgments of experienced, reliable observers provide the most valid way of measuring any changes that occur in these behavioral events during therapy. This strategy is also consistent with the WHO model of chronic behavioral disorders in that it views adult stuttering as consisting of an impairment, a disability, and a handicap. Several basic and optional measures of stuttering severity and speech naturalness were proposed for determining the extent to which a stut-
ASSESSMENT
tcring
disability
ir\ not clear should
327
OF L>ISAHIL,ITY
decreases
if changes
bc described
during
the course
occurring
of treatment.
in speaking
as “treatment
behavior
Although
during
in “speech
or as an increase
effects”
it
thcrapq
the measures proposed are intended to quantify any such skills.” “treatment effects” or changes in “speech skills” that may occur. Thus. if samples recorded in a clinical setting are compared to those recorded away from the clinic, the generality of such “treatment cffecty” or the extent to which a client can employ his or her “speech skills”
;ICI-ass settings
sample
settings
can bc assessed. These recordings do need to client encounter\ routinely during activities of daily living as well as those reported to bc ;I problem. or suggc\ted as problematic by the S-24 scale. in order to increase the representativeness of the samples assessed. I:inally, comparisons samples recorded at regular intervals over time permit assessment of the permanence of “treatment effects” or the durability ofa client’s “speech skills.” From that
;I
of
one pcr\pectivc.
increases
uralness
indicate
would
other.
a need for
about
the efficacy
in stuttering ;I relapse
further
and/or
in
“speech
skill”
of the treatment
training.
employed
in speech nat-
decreases
“treatment
effects”:
Of
from
course.
the
inferences
can be drawn
from
either
perspective. The
assessment
about lized will
not provide
fails who
speech
singly
during
for
current
[ 1992]).
when
(e.g..
Prins which
sufficient,
were
observed
treatment.
This
kind
of information.
studies
could
that
procedures.
in isolation
procedures
found
be
tcstcd
in
or even
in the client’s which
treatments
be obtained
would
for
through
evaluate
the
to be most
a series
effects
effective
is
chronic
and combination.
appropriately
or
for adults
known
that
design
OLII- undcr-
compare
not
are necessary.
uti-
strategy
it works
treatments
and it is
of current
were
this
to expand
succeeds.
of procedures
arc to be improved,
could
needed
most
if the cft’icacy
of those
studies
example.
information that
the changes
and after
individual
the generality subject
For
provides
procedures Unfortunately.
;I treatment
or in combination.
single-subject
treatment’s
stutters.
of information why
significance
stuttering
who
described
treatment
and Andrews
responsible
of critical
was
of a variety
Neilson
procedures.
adult
not.
consist
and
partly
the kind
it does
stutter
[ IYE]
client
of the reasons
when
that
of the specific
\vith a specific
standing
of
strategy
the cf’ficacy
of ;I Then.
in singlc-
controlled
group
studies. Treatment
could
also
stuttering tering skill\
failures.
which
provide
crucial
therapies.
When
and increasing practiced
treatment
speech
in therapy
have
reccivcd
information
for
little
systematic
improving
is not effective
naturalness.
when
OCCLKS incon\istcntly.
in reducing
transfer when
study,
the cff‘icacy
of
stut-
of the speech there
are post-
328
R. F. CURLEE
treatment relapses in speaking performance, it is not known if the fault lies with the treatment procedures, with a clinician’s application of those procedures, with the level of speech skill achieved by the client, with the client’s practice habits or motivation, or with some other variable(s). Initial research in this area could employ detailed case studies to help identify variables that might be contributing to treatment failures of specific clients that would then be followed by single-subject studies that modified those variables identified in order to confirm or rule-out their significance. Alternatively, if stuttering events that are perceived by listeners are only an incomplete, perhaps unrepresentative subset of the population of speech production events of those who stutter, further insight into treatment failures might be obtained from observations that focus on the impairment level of stuttering. It is possible, for example, that the neuropsychological and neurophysiological events that precede and accompany the audible and visible speech events of stuttering may affect the extent to which speech skills acquired in treatment will be used outside of treatment, the extent to which such speech skills are performed automatically, and/or the extent to which a stuttering disability, and its handicaps, will be resolved permanently. Systematic assessments of the efficacy of the treatments utilized by a profession are essential to the maintenance of the clinical integrity of any profession. Few disorders pose greater challenges to the assessment of treatment efficacy than does stuttering. Nevertheless, it is of critical importance that a standard set of procedures be adopted for evaluating the treatment outcomes of adults who stutter so that significant variations in such outcomes, from one procedure or clinic to another, can be reliably identified. In addition, it is similarly important that systematic studies be initiated to identify the specific therapy procedures that contribute the most to successful treatment outcomes and the variables that are largely responsible for treatment failures. Otherwise, it is unlikely that our treatment of adults who stutter will improve substantially in the foreseeable future. ACKNOWLEDGMENT Preparation of this article was supported in part by National Institute of Child Health and Human Development NIH grant 2 R44 HD2620902A1.
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ASSESSMENT
329
OF DISARIL,ITY
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of
ASSESSMENT OF DISABILITY
Wood.
F.,
Stump.
D..
McKeehan.
( 1980) Patterns ofrcgional ing aloud by stutterer\ dence for inadequate &
LA,I,qutrgc~,
Rcccived
9.
33I
A..
S.. and Proctor.
both on and oft‘ haloperidol left frontal
activation
141-144.
and accepted
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cerebral blood tlow during attempted
January
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medication:
during stuttering.
J.
rcadEviHrtrirl
The propod strategy for evaluating the efficacy of’ treatment for adult\ ti ho stutter involves repeated ahse\smcnt\ ofst~ttcring and speech naturalness i’-om conversation ample\ recorded in and away from the clinic. This stl-:lteg)’ conceptualircs chronic stuttering among adult\ as ;I di\or-dcr that is hc\t vicwd and measured at three level\: impairment. disability. and handicap. .A common goal of current treatments for adult stuttering i\ the reduction or climinatlon of the disability of stuttering. Therctbre. the evaluation of treatment efi’icac~ is logically and most directly related to mea\urc\ of stuttering disability. Both basic and optional mca\ures of the diahilith, of stuttering arc propod and discussed.
INTRODUCTION In 1973 a review tering
is
Andrews, about
of behavior
a comparatively 1973.
p. 408).
the reliability
can be found
1973: mcnt.
(Coyle it was
quency tering
1975). widely
counts
There
counts
of these until
events
are now
1981
findings
measures
of stuttering
been apparent
; MacDonald that
sufficiently
(Kully
and
concerns for
and Martin.
on event-by-cvcnt
the effect\
data indicating
be misplaced
“\tuf-
on the loci ofstutteriny
recently, were
that
(Ingham
increasing
it has
low agreement
for quantifying
may
however.
example,
1979: Curlee.
stated
to measure”
of perceptual For
believed,
of stuttering
measure
clients.
frequency
that time.
evidence
In spite
and stuttering
disorder
and validity
and Mallard.
Young.
as 21primary
Since
in the literature.
some time that listeners events
therapy
simple
agrecmcnt high for
of treatment that
and
such Bohcrg.
ago-eeon fretheir with
confidence Ic)XX),
USC \tutin and
320
R. F. CURLEE
subsequent efforts to develop procedures that yield measures of satisfactory reliability have achieved only modest success to date (Cordes et al., 1992). It should be noted also that persuasive arguments have been advanced in recent years that challenge the value of listener judgments of stuttering even if those judgments were reliable. Perkins (1990) claims, for example, that a speaker’s subjective experience of the loss of control of the speech production process is the only valid indicator of the occurrence of stuttering events. Others, such as Adams and Runyan (IYSI), Freeman (l984), and Smith (l990), have argued that the events that listeners perceive as stuttering events are only a subset of the abnormal speech production events that characterize the speech of those who stutter. Such arguments have selected neuropsychological and/or neurophysiological variables, rather disruptions in speech, as the most appropriate level at which to study and describe stuttering. Stuttering has been studied at various levels of observation, from central nervous system activity to perceptions of the acoustic product of the speech production process. All levels have provided useful information, and it is not yet clear which level(s) will be most valuable to our understanding of the nature of stuttering and of how best to manage it. Different levels of observation rely on different definitions and different measures of stuttering phenomena. A useful perspective for conceptualizing and evaluating the clinical management of a chronic, behavioral disorder, which Prins (1991) applied to stuttering, is that of the World Health Organization (WHO). This model views disorders of stuttering as having three levels: I. An impairment, which would include all of the neuropsychological and neurophysiological events that immediately precede and accompany the audible and visible events of stuttering. 2. A disahili~y, which would comprise the audible and visible events that are the behavioral manifestations of stuttering. 3. A handicap, which would consist of the disadvantages that result from reactions to the audible and visible events of a person’s stuttering and that would include those of the person who stutters. This view of stuttering appears to be particularly useful for differentiating the goals of different clinical management approaches and for organizing the different measures of treatment efficacy that are pertinent to those goals. There is much more information about the speech disabilities of those who stutter than there is about the nature of their speech production disruptions or about the kinds of handicaps that may result. Indeed, the nature of the disruptions in the planning and execution of speech
ASSESSMENT
that
OF
results
in the audible
is not well-understood. of those often
who
result
handicaps 1992).
have
ber
of other
assessing
handicaps
Stuttering
Inventory
Attitudes
(Watson.
arc needed of those
posed
from 1967).
was
stutter.
derived
from
Stuttering rarely
3.
A primary
Measures of
suited Thus,
this
stuttering
current
article
of reliable
signs
of stuttering
uating The
situations
by Costello stuttering from
the clinic.
conversational several
years
even
these
few
and mcaand handito be pro-
and inferences: event
until
at other
childhood
it has
levels
of
into
adult
life
is to eliminate
OI
remissions.
procedures
events
and
that comprise
most are
are well
systematic
valid
based
focus are.
comparisons
best
who stutter.
measures
on the
of an adult
perceptual
acquainted
;I practical.
on a primary
therefore.
of adults
of treatment
the
that
who
and that
of stuttering
procedures
and time provide
with of such
appropriate
judg-
the clinical measures
way for eval-
of treatment.
assessment
and lngham adults’
from
events
that
are those observers
the efficacy proposed
10X4),
workers
strategy
behavioral
the efficacy
proposes
disability
of
stuttering.
treatment
for assessing
to
and control.
spontancou\
of the behavioral
ments across
of adult
et al.,
disubilitics.
of events
treatment
prove
scales for
of study.
as a behavioral
and visible
et
the Perception
from
assumptions
persis;ts
goal of current the audible
the disability goal
that
extended.
useful
stuttering
efficacy
prediction
well
Ingham.
and a num-
1 could
(Craig of
units
descriptions
better
behavior
decrease 4.
that
evidences
scales
treatment
less
of Communication
be apparent
the following
provide
I991
the impairments.
which
(Onslow
1980).
include
of observation.
and rate
et al..
perceptions
is best conceptualized
observation
(Gow
Inventory
of control
The
been demonstrated 2.
the
It should
levels
lo quantify
who
Stuttering
locus
and arc even
Potentially
stuttering
of employers’ 1991).
(Wood
reactions
them.
and personal/social
(Alphonse.
(Woolf,
that different
study
impairment.
that result 198X),
with
and articulatory
flow
measures
stuttering
and Calver.
sures
I.
ofa
assessment
examples
blood
interact
intervals
durations
physiological
indices
caps
systematic
disability
and emotional
vocational.
phonation
cerebral
be useful
the
littlc
of vowel
regional
of a stuttering
who
educational,
received
variability
events
the cognitive
as those
Nevertheless,
IYE),
(Craig
as well
in significant
al..
and
and visible
Likewise.
stutter,
understood.
121
DISAHII~I’I’Y
speech Samples partners.
posttreatment,
strategy (1984) samples
is consistent
and involves
that are recorded
should
involve
extend
from
with
repeated
different pretreatment
and be supplemented
that advocated assessments
both
of
in and away
speaking samples by reports
tasks
and
through of family
322
R. F.CURLEE
members and occasional covert samples. Prior to the initiation ment, the following measures should be obtained to document ture and severity of a stuttering disability.
BASIC MEASURES
OF STUTTERING
of treatthe na-
DISABILITY
These measures are considered to be necessary components of any assessment of stuttering. They will be sufficient, however, only if no stuttering events are observed in a speech sample and if the sample’s speech naturalness ratings fall within the range of those expected of nonstuttering speakers. It should also be noted that elevated scores on the S-24 scale could indicate the need to obtain recordings of additional speech samples. If, however, the S-24 score is not elevated, no stuttering events are observed in the speech samples assessed and speech naturalness ratings are comparable to those of nonstuttering speakers, there should be no need to obtain further quantification unless there is reason to report a severity rating derived from standardized procedures. The basic, obligatory measures needed to assess a stuttering disability include: 1. frequency of stuttering (in percentage of syllables [% SS] or percent words [% WS] stuttered); 2. ratings of speech naturalness; 3. administration of the S-24 Scale (Andrews and Cutler, 1974).
OPTIONAL SEVERITY MEASURES STUTTERING DISABILITY
OF
Some of these measures should be selected to supplement the basic measures listed above whenever a sample contains stuttering events or receives elevated speech naturalness ratings. The specific measures selected should be determined by the characteristics of clients’ speech and stuttering events. For example, if a client’s longest sound prolongation or tense pause was less than a second, efforts to quantify their typical duration would likely have little clinical significance. In contrast, careful assessments of the duration of long stuttering events may provide early indications during treatment that a client’s severity of stuttering is decreasing. Even if a sample is free of stuttering events but receives elevated speech naturalness ratings, such measures as speech rate may provide insight into the reasons for the elevated rating. Many times, all of these measures may be needed. Finally, it should also be noted that additional, supplementary measures may also be
ASSESSMENT
OF DISABlI,ITY
needed in order to better assess the idiosyncratic stuttering events and patterns of speech of some clients. For example, the eye contact of many stuttering clients during conversations is frequently inappropriate, such behavior may be targeted for change in therapy. If so. it would be important to devise optional measure(s) of eye contact during video recordings of a client’s speech samples. Optional measures that will be needed most often to further quantify the severity of a stuttering disability include: I. duration of both typical and longest stuttering events (in seconds and/or number of repeated units); 2. length of typical and longest stutter-free segments of speech (in syllables or words): 3. rate of speech in syllables (SPM) or words (WPM) per minute: 4. administration of a standardized scale such as the Stuttering Severity Index (Riley. 1974).
MEASUREMENT
PROCEDURES
Descriptions of the optional severity measures listed above can be found in a number of refercnccs tc.g., Costello and Ingham. 1984). all of these measures will be used to assess the speech Ordinarily. samples of adults who stutter that were recorded prior to treatment in order to quantify a client’s stuttering disability in adequate detail. Samples obtained at termination of treatment and final posttreatment samples would utilize only those measures needed to further quantify any remaining stuttering events or unnatural speech patterns. Several of these measure are also intended to provide more sensitive indicators of changes in stuttering. both increases and decreases, during the intervention process. which may not be readily apparent in frequency of stuttering measures. Such measures (e.g., rate of speech) may also provide additional insight into the reasons for a client receiving elevated speech naturalness ratings. In contrast. the basic measures of stuttering disability are intended to indicate whether or not someone has stuttered during a recorded sample and, if so, how much. In addition. speech naturalness ratings should provide evidence of a client’s use of any compensatory speaking behaviors in the sample that sound unnatural or that draw adverse attention from listeners. Finally, the S-24 Scale is intended to suggest communication interactions away from the clinic that warrant observation and assessment. Guidelines for obtaining and interpreting these measures will be summarized briefly in the paragraphs that follow. There are no standard procedures in current use for counting stut-
324
R.F.CURLEE
tering events that are widely accepted. For example, some clinicians restrict counts to specific disfluency topologies, others count any speech disfluency that is perceived as unusual, abnormal, or effortful as stuttering. The development and adoption of a standardized set of such procedures would likely reduce at least some of the variability in stuttering counts often reported among different clinics and clinicians. Cordes et al. (1992) found that listeners who are well acquainted with the clinical signs of stuttering and who evidence high intraobserver agreement are also likely to evidence higher interobserver agreement. Consequently, the assessment procedures that will be described are best conducted by individuals with a number of years experience working with stuttering adults and who also evidence self-agreement levels consistently in excess of 0.80 when counting stuttering events. The following guidelines, which could also be used with children who stutter, illustrate one way of counting stuttering events of adults. Count only dysfluencies that are perceived as stuttered events rather than all disfluencies. Each syllable or word should be counted as either stuttered or not stuttered and should be counted only once regardless of how it was disrupted. If sounds. syllables, words, or phrases are repeated as if to facilitate initiation of the following word, only the syllable or word that follows is counted as stuttered. Count the number of syllables or words stuttered twice. If these counts agree, use that number to calculate % SS or % WS. If they do not agree, count stuttering events again and use the median or modal count for calculations. These guidelines view stuttering events to be a perceptual “threshold phenomenon” (Martin and Haroldson, 1981) and all speech events perceived to be stuttered are counted, regardless of the type of disfluency involved. This approach differs from those that define stuttering as a group of specific behaviors, typically the kernel characteristics of stuttering that were proposed by Wingate (19641, and that count only specific types of disfluencies as stuttering events. Empirical comparisons of these two approaches have found “perceptual threshold” counts to result in similar (Curlee, 1981) or higher listener agreement (Martin and Haroldson, 1981). As was noted above, there are no standardized procedures for training judges to identify stuttering events reliably or for monitoring or for recalibrating such judges’ performance following training. Consequently, there is an urgent need to develop such training and monitoring procedures or to establish special facilities that would assess recorded speech samples much as medical laboratories now assess fluid and tissue samples. In the absence of such standardization, one way to increase the precision and reliability of measurements is to rely on the
ASSESSMENT
OF DISABILITY
325
central tendency of repeated measures as was proposed in the above guidelines. Ratings of speech naturalness should utilize the procedures described by Martin and colleagues (1984). Those portions of recorded speech samples that are assessed for frequency of stuttering events should also be rated in terms of speech naturalness every 30 set by at least three to five independent raters. The median rating of each segment should be used to determine both the median and range of all ratings during a sample and should be compared to the ratings obtained from nonstuttering speakers. It should be noted that speech naturalness ratings need to be obtained from a much larger number of nonstuttering speakers so that the resulting data base will likely encompass the range of fluent and nonfluent speakers in the nonstuttering population. Such data would also permit the reporting of stuttering adults’ speech naturalness ratings as standard z-scores, which would also facilitate comparison of a client’s ratings to those of the nonstuttering population. Administration of the S-24 Scale (Andrews and Cutler, 1974) is included as a basic measure because of the need to select extra-clinic communication settings that may be troublesome for adults who stutter. Thus, this scale is not used to evaluate clients’ attitudes about speaking but rather as an indicator of the types of speaking tasks and situations that may be causing a client current stuttering difficulties. Scale items that are scored “1” can be utilized to identify the type and number of extra-clinic samples that need to be obtained, especially during transfer and follow-up assessments, so that arising or persisting difficulties with stuttering can be monitored and evaluated appropriately.
SAMPLES Prior to the initiation of treatment, at least two in-clinic conversations should be videotaped, one face-to-face, the other via telephone. Each should include at least 500 words, or 7.50 syllables, of the client’s speech. Neither conversational partner should be familiar to the client, and each sample should include segments intended to be stressful. Oral reading samples should also be recorded if it is reported that this task poses special difficulties or is of special importance to the client. At least three samples of similar length should be recorded away from the clinic. One should involve a conversational partner who is familiar to the client and who will be able to continue as a conversational partner through posttreatment samples. Remaining samples should be selected from those reported to be especially difficult for the client or those that elicited “ 1” responses from the client on the S-24 Scale. Large
326
R. F. CURLEE
differences in frequency of stuttering across samples (e.g., >25%) may indicate the need for replicating or obtaining additional samples. If an intensive treatment schedule (e.g., >I5 hr weekly) is utilized to establish speech that is free of stuttering, initial sampling procedures should be repeated before beginning transfer training if the efficacy of transfer training is to be evaluated. If a less intensive treatment schedule is utilized, outside clinic samples with the familiar partner and of one problematic situation should be recorded on alternate weeks until the client is ready for transfer training. At that time, initial sampling procedures should be replicated if the effect of transfer training is to be assessed. During transfer training, samples of at least two extra-clinic conversations should be recorded regularly until treatment is terminated. Early in training, such samples should be recorded at least weekly and should include one with the familiar conversation partner until there is no stuttering and speech naturalness ratings are within normal limits (WNL) for four consecutive samples. Later, only monthly samples may need to be recorded so long as speech naturalness ratings remain WNL and no stuttering events are observed on any sample. Additional recordings would be used to sample those reported as troublesome by the client or those that are suspected as problematic based on monthly administrations of the S-24 Scale. With prior written permission of the client, monthly covert samples can be used to evaluate a client’s speech when he or she is presumed to be unaware of being assessed. Initial sampling procedures should be repeated at termination of transfer training and at 6-month and yearly intervals thereafter so long as contact with clients is maintained.
SUMMARY The strategy that has been proposed for evaluating treatment efficacy relies on assessments of a client’s stuttering disability from recorded speech samples obtained in different settings prior to and at regular intervals during and following treatment. It was argued that stuttering is, in essence, a behavioral event, that current treatment procedures focus on modifying or eliminating these behavioral events, and that the perceptual judgments of experienced, reliable observers provide the most valid way of measuring any changes that occur in these behavioral events during therapy. This strategy is also consistent with the WHO model of chronic behavioral disorders in that it views adult stuttering as consisting of an impairment, a disability, and a handicap. Several basic and optional measures of stuttering severity and speech naturalness were proposed for determining the extent to which a stut-
ASSESSMENT
tcring
disability
ir\ not clear should
327
OF L>ISAHIL,ITY
decreases
if changes
bc described
during
the course
occurring
of treatment.
in speaking
as “treatment
behavior
Although
during
in “speech
or as an increase
effects”
it
thcrapq
the measures proposed are intended to quantify any such skills.” “treatment effects” or changes in “speech skills” that may occur. Thus. if samples recorded in a clinical setting are compared to those recorded away from the clinic, the generality of such “treatment cffecty” or the extent to which a client can employ his or her “speech skills”
;ICI-ass settings
sample
settings
can bc assessed. These recordings do need to client encounter\ routinely during activities of daily living as well as those reported to bc ;I problem. or suggc\ted as problematic by the S-24 scale. in order to increase the representativeness of the samples assessed. I:inally, comparisons samples recorded at regular intervals over time permit assessment of the permanence of “treatment effects” or the durability ofa client’s “speech skills.” From that
;I
of
one pcr\pectivc.
increases
uralness
indicate
would
other.
a need for
about
the efficacy
in stuttering ;I relapse
further
and/or
in
“speech
skill”
of the treatment
training.
employed
in speech nat-
decreases
“treatment
effects”:
Of
from
course.
the
inferences
can be drawn
from
either
perspective. The
assessment
about lized will
not provide
fails who
speech
singly
during
for
current
[ 1992]).
when
(e.g..
Prins which
sufficient,
were
observed
treatment.
This
kind
of information.
studies
could
that
procedures.
in isolation
procedures
found
be
tcstcd
in
or even
in the client’s which
treatments
be obtained
would
for
through
evaluate
the
to be most
a series
effects
effective
is
chronic
and combination.
appropriately
or
for adults
known
that
design
OLII- undcr-
compare
not
are necessary.
uti-
strategy
it works
treatments
and it is
of current
were
this
to expand
succeeds.
of procedures
arc to be improved,
could
needed
most
if the cft’icacy
of those
studies
example.
information that
the changes
and after
individual
the generality subject
For
provides
procedures Unfortunately.
;I treatment
or in combination.
single-subject
treatment’s
stutters.
of information why
significance
stuttering
who
described
treatment
and Andrews
responsible
of critical
was
of a variety
Neilson
procedures.
adult
not.
consist
and
partly
the kind
it does
stutter
[ IYE]
client
of the reasons
when
that
of the specific
\vith a specific
standing
of
strategy
the cf’ficacy
of ;I Then.
in singlc-
controlled
group
studies. Treatment
could
also
stuttering tering skill\
failures.
which
provide
crucial
therapies.
When
and increasing practiced
treatment
speech
in therapy
have
reccivcd
information
for
little
systematic
improving
is not effective
naturalness.
when
OCCLKS incon\istcntly.
in reducing
transfer when
study,
the cff‘icacy
of
stut-
of the speech there
are post-
328
R. F. CURLEE
treatment relapses in speaking performance, it is not known if the fault lies with the treatment procedures, with a clinician’s application of those procedures, with the level of speech skill achieved by the client, with the client’s practice habits or motivation, or with some other variable(s). Initial research in this area could employ detailed case studies to help identify variables that might be contributing to treatment failures of specific clients that would then be followed by single-subject studies that modified those variables identified in order to confirm or rule-out their significance. Alternatively, if stuttering events that are perceived by listeners are only an incomplete, perhaps unrepresentative subset of the population of speech production events of those who stutter, further insight into treatment failures might be obtained from observations that focus on the impairment level of stuttering. It is possible, for example, that the neuropsychological and neurophysiological events that precede and accompany the audible and visible speech events of stuttering may affect the extent to which speech skills acquired in treatment will be used outside of treatment, the extent to which such speech skills are performed automatically, and/or the extent to which a stuttering disability, and its handicaps, will be resolved permanently. Systematic assessments of the efficacy of the treatments utilized by a profession are essential to the maintenance of the clinical integrity of any profession. Few disorders pose greater challenges to the assessment of treatment efficacy than does stuttering. Nevertheless, it is of critical importance that a standard set of procedures be adopted for evaluating the treatment outcomes of adults who stutter so that significant variations in such outcomes, from one procedure or clinic to another, can be reliably identified. In addition, it is similarly important that systematic studies be initiated to identify the specific therapy procedures that contribute the most to successful treatment outcomes and the variables that are largely responsible for treatment failures. Otherwise, it is unlikely that our treatment of adults who stutter will improve substantially in the foreseeable future. ACKNOWLEDGMENT Preparation of this article was supported in part by National Institute of Child Health and Human Development NIH grant 2 R44 HD2620902A1.
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ASSESSMENT
329
OF DISARIL,ITY
Alphonse, P. The effect of speech motor training on stutterers’ physiology. In: Spcrc,ll Motor Control ctnd Strrttcrin,q (Peters, Hulstijn, W.. eds.). Amsterdam: Elsevier Science, 1991.
speech H. and
Cutler, J. (1974) Stuttering therapy: The relation in symptom level and attitude, JorrrttnI c?f‘Spc~c~ch B Hcctritlg Disorders. 39. 3 13-3 IY.
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Cordes, A., Ingham, R.. Frank. P.. and Ingham. J. ( IYY2) Time-interval analysis of interjudgc and intra.judge agreement for stuttering event -judgments. Jo~trnrrl of’ Sprcch & Hctrrin,q Rcscrtrch. 35. 483-4Y4. Costello,
J.. and Ingham.
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In: W.,
Craig. A., and Calver, Studies of perception
P. (1941) Following up on treated stutterers: of fluency and job status. Jotrrnrrl c?f‘Spccch & Hcnritt,q Rcscrr~~~l~. 34, 27Y-284.
Craig. A., Franklin, J.. and Andrews. G. (lYX4) A scale to measure locus of control of behaviour. British Jortrtlctl c?f’Mctiictrl Psyc~hology, 57. 173-180. Coyle, M.. and Mallard, A.R. (1979) Word-by-word analysis of observer agreement utilizing audio and audiovisual techniques. Jortrnul c?f’Flrtc~ncy Disorders,
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agreement
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F. Laryngeal
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lngham, R., and Andrews. G. (1973) Behavior therapy and stuttering: A review. Journal of.5pccc.h & HrarinR Disorders, 38, 405-44 I. Kully. D.. and Boberg, E. (1988) An investigation of inter-clinic agreement in the identification of fluent and stuttered syllables. Journal of' Flrrcttcy Disorders, 13, 309-3 1X.
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Prins, D. Theories of stuttering as event and disorder: Implications for speech production processes. In: Speech Motor Control and Stuttering (Peters, H., Hulstijn, W., and Starkweather, C.W., eds.). Amsterdam, Elsevier, 1991, pp. 571-580. Prins, D. Management of stuttering: Treatment of adolescents and adults. In: Stuttering and Related Disorders of Fluency (Curlee, R., ed.). New York: Thieme Medical Publishers, 1992, pp. 115-138. Riley, G. (1974) A stuttering severity instrument for children Journal of Speech & Hearing Disorders, 27, 314-322. Smith, A. (1990) Toward a comprehensive mentary. Journal of Speech 6; Hearing
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Watson, J. (1988) A comparison of stutterers’ and nonstutterers’ affective, cognitive and behavioral self-reports. Journal of Speech & Hearing Research, 3 1, 377-385. Wingate, Speech Woolf,
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G. (1967) The assessment
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Journal
avoidance
of
ASSESSMENT OF DISABILITY
Wood.
F.,
Stump.
D..
McKeehan.
( 1980) Patterns ofrcgional ing aloud by stutterer\ dence for inadequate &
LA,I,qutrgc~,
Rcccived
9.
33I
A..
S.. and Proctor.
both on and oft‘ haloperidol left frontal
activation
141-144.
and accepted
Sheldon,
cerebral blood tlow during attempted
January
1993.
medication:
during stuttering.
J.
rcadEviHrtrirl