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Patient-Based Outcomes in Patients With Primary Tinnitus Undergoing Tinnitus Retraining Therapy
Julie A. Berry, MD;
Susan L. Gold, MAud, CCC SLP-A;
Ellen Alvarez Frederick, MAud, CCC-A;
William C. Gray, MD;
Hinrich Staecker, MD, PhD
Arch Otolaryngol Head Neck Surg. 2002;128:1153-1157.
ABSTRACT
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Objective To determine whether the Tinnitus Handicap Inventory (THI), a validated
patient-based outcomes measure, may improve our ability to quantify impact
and assess therapy for patients with tinnitus.
Design Nonrandomized, prospective analysis of 32 patients undergoing tinnitus
retraining therapy (TRT). Assessment tools included comprehensive audiology,
a subjective self-assessment survey of tinnitus characteristics, and the THI.
Tinnitus Handicap Inventory scores were assessed at baseline and 6 months
following TRT.
Results Baseline analysis revealed significant correlation between the subjective
presence of hyperacusis and higher total, emotional, and catastrophic THI
scores. Tinnitus Handicap Inventory scores correlated with subjective perception
of overall tinnitus effect (P<.001). Mean pure-tone
threshold average was 17.4 dB, and mean speech discrimination was 97.0%. There
were no consistent correlations between baseline audiologic parameters and
THI scores. Following 6 months of TRT, the total, emotional, functional, and
catastrophic THI scores significantly improved (P<.001).
Loudness discomfort levels also significantly improved (P .02).
Conclusions There is significant improvement in self-perceived disability following
TRT as measured by the THI. The results confirm the utility of the THI as
a patient-based outcomes measure for quantifying treatment status in patients
with primary tinnitus.
INTRODUCTION
TINNITUS IS a common and potentially debilitating disorder that can
have a profound impact on patients' lives. It is estimated to affect approximately
36 million Americans, or about 17% of the general population.1 Unfortunately,
efforts at understanding and treating this disorder have been limited by an
inability to objectively assess tinnitus and its sequelae. For example, attempts
to find a relation between subjective improvement and psychoacoustical descriptions
of tinnitus have not been successful.2-3 The
development of patient-based outcome measurements is significantly improving
our ability to objectify perceived disability and better quantify the impact
of conditions such as tinnitus in which manifestations are largely subjective.
Furthermore, changes in these outcome measures allow a more statistically
rigorous assessment of treatment efficacy. For example, the use of nonvalidated
subjective tinnitus ratings scales allows assessment of improvement only within
a particular patient. The use of broadly validated scales allows comparisons
between patients and even between institutions.
Of the various tinnitus-specific self-assessment tools available, the
Tinnitus Handicap Inventory (THI) is desirable for its ease of administration,
incorporation of functional as well as emotional constructs, good construct
validity, and strong internal consistency and test-retest reliabilities.4-5 The THI is a 25-item survey that provides
a total score and 3 subscale scores. The functional subscale (11 items) addresses
role limitations in the areas of mental, social/occupational, and physical
functioning (eg, difficulty concentrating and trouble falling asleep). The
emotional subscale (9 items) includes a range of affective responses to tinnitus,
such as feelings of depression, anger, and anxiety. The catastrophic subscale
(5 items) reflects the most severe reactions to tinnitus, such as desperation,
loss of control, and failure of coping mechanisms. The THI has been used to
assess response to an array of treatment modalities for tinnitus.6-8
While various surveys and questionnaires have been applied to rehabilitative
treatments such as cognitive-behavioral therapy,9 to
our knowledge, there has been no patient-based outcomes analysis of response
to habituation-based counseling. The following investigation addresses self-perceived
disability in patients undergoing tinnitus retraining therapy (TRT), a directive
counseling method aimed at habituation of both the reaction to tinnitus and
the perception of the tinnitus signal itself.10-11 The
aim or TRT is to actively change the way the patient thinks about tinnitus
and reverse the distress produced by tinnitus. Wearable low-level broadband
noise generators, which do not produce a masking signal, are used to facilitate
habituation.
The goals of this study were to quantify the impact of tinnitus in a
population of patients with primary tinnitus by comparing a set of audiologic
parameters, validated patient-based THI results, and responses to a subjective
self-assessment survey of tinnitus characteristics. Additionally, we wished
to apply the THI in a prospective assessment of the therapeutic efficacy of
TRT.
PATIENTS, MATERIALS, AND METHODS
PATIENT SELECTION
Thirty-two patients of the University of Maryland Tinnitus and Hyperacusis
Center, Baltimore, were prospectively studied between October 1999 and January
2001. Prior to initiation of the TRT protocol as described by Jastreboff et
al,11 patients underwent a standardized intake
assessment including a full history and physical examination by an otolaryngologist
and magnetic resonance imaging with gadolinium to rule out retrocochlear disease.
AUDIOLOGIC TESTING
Standard audiologic testing included audiometry for pure-tone average
(PTA) and speech discrimination score (SDS), reflex testing, and otoacoustic
emission testing. Specialized audiometric tests included pitch matching as
well as determination of dynamic range, loudness discomfort level (LDL), and
loudness matching and minimum masking levels. The specific audiologic parameters
analyzed in this investigation were PTA and SDS, LDL, and loudness matching
and minimum masking levels. Audiology was repeated at the 6-month visit. Scores
for LDL were only remeasured on patients who had positive test scores at the
first visit. All patients completed an initial subjective survey of tinnitus
characteristics specifically analyzed for the duration of the tinnitus, percentage
of time aware of the tinnitus, and the subjective presence or absence of hyperacusis
(as manifested by sound tolerance problems). Patients completed a follow-up
version at the 6-month visit.
TINNITUS HANDICAP INVENTORY
The THI was administered at the initial visit and 6 months following
counseling and the incorporation of desensitization via sound generators.
Each of the 25 items had 3 potential answers, with "yes" assigned 4 points;
"sometimes," 2 points; and "no," 0 points. This yielded a total score ranging
from 0 to 100, with 0 being asymptomatic and 100 being the worst constellation
of complaints. Maximum scores for the emotional, functional, and catastrophic
subscales were 36, 44, and 20, respectively. Permission for the use of this
survey was obtained.
STATISTICAL ANALYSIS
All statistical analyses were performed using Statistical Program for
the Social Sciences 9.0 (SPSS Inc, Chicago, Ill). Correlation analysis was
performed using a linear regression model providing Pearson product-moment
correlation values and associated 1-tailed significance values. Significance
values for comparison between initial and 6-month scores were generated using
a simple paired samples t test. A P value of .05 or less was considered significant.
RESULTS
BASELINE ASSESSMENT
The mean ± SD age of the study population was 54.5 ± 11.0
years, ranging from 18 to 76 years; 78% were men. Table 1 summarizes the baseline audiologic parameters, THI scores,
and subjective tinnitus characteristics of the study population. The mean
PTA and SDS were within the normal range. The mean right and left LDL scores
were 103.8 and 102.7, respectively. The mean duration of tinnitus was approximately
7.4 years, with a broad range of 1 month to 32 years. Subjective sound tolerance
problems were present in more than one half of the baseline population. Average
baseline THI scores were higher in our patient population than in previously
published reports (Table 2).
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Table 1. Baseline Audiologic Parameters, Tinnitus Handicap Inventory
Scores, and Subjective Tinnitus Characteristics*
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Table 2. Tinnitus Handicap Inventory Scores at Initial Visit Compared
With Published Norms*
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Pearson correlation and significance values between baseline THI scores
and audiologic parameters are given in Table 3. There
were no consistent statistically significant correlations. A comparison of baseline THI scores and subjective tinnitus characteristics
is given in Table 4. This reveals
a significant correlation between the subjective presence of sound tolerance
problems and higher total THI scores (r = 0.368; P = .04) as well as higher emotional (r = 0.392; P<.03) and catastrophic subscale
scores (r = 0.382; P = .03).
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Table 3. Pearson Product-Moment Correlations Among Baseline Tinnitus
Handicap Inventory Scores and Audiologic Parameters*
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Table 4. Pearson Product-Moment Correlations Among Baseline Subjective
Tinnitus Characteristics and Tinnitus Handicap Inventory Scores
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OUTCOMES FOLLOWING TRT
A comparison of audiologic parameters at the initial visit and the 6-month
follow-up after TRT intervention is given in Table 5. Right and left PTA and SDS remained within normal limits.
Nine patients initially presented with tinnitus and hyperacusis (as determined
by LDL scores). In these patients the LDL showed a statistically significant
improvement following TRT (P<.05).
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Table 5. Comparison of Audiologic Parameters Between Baseline and 6-Month
Visits Following Tinnitus Retraining Therapy*
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A comparison of THI scores between the initial visit and the 6-month
follow-up is shown in Figure 1.
After 6 months of TRT, there was a highly significant improvement in the THI
total score and all 3 subscale scores (P<.001).
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Comparison on Tinnitus Handicap Inventory scores between initial
visit and 6 months following tinnitus retraining therapy (N = 32). Error bars
indicate SD.
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COMMENT
SELECTION OF PATIENT-BASED OUTCOMES MEASURES
The need to define better the impact of tinnitus and to quantify treatment
response more accurately has led to the introduction of a variety of validated,
patient-based outcome measures. An initial challenge was to identify the optimal
assessment tool for use in our particular study population that would most
appropriately quantify the expected functional, emotional, and psychosocial
improvements following TRT. While the available tinnitus-specific instruments
generally demonstrate good internal consistency reliability, there are a number
of limitations. The Tinnitus Cognitions Questionnaire, designed to assess
negative and positive cognitions associated with tinnitus, and the Tinnitus
Reaction Questionnaire, designed specifically to measure psychological distress,
may be too narrow in scope.12-13 The
Tinnitus Effect Questionnaire is relatively broad14 but
is among those instruments that fail to differentiate clearly between tinnitus
disability (functional limitations) and handicap (psychosocial impact).15 The Tinnitus Handicap Questionnaire (THQ), developed
in 1990 by Kuk et al,16 is a 27-item questionnaire
that quantifies the social, emotional, and physical sequelae of tinnitus (factor
1), hearing deficiencies (factor 2), and the patient's view of the tinnitus
(factor 3). The overall internal consistency reliability was high, as determined
by a Cronbach  of .94; however, of the subscales only factor 1 and
factor 2 had good reliability. The THI was developed in 1996 by Newman et
al4 to meet criteria not fulfilled by previous
patient-based outcome measures. The total scale yielded excellent internal
consistency (Cronbach of .93), with moderately high consistency for
the emotional, functional, and catastrophic subscales. Construct validity
analysis revealed low correlation between the THI results and pitch and loudness
ratings and a weak but significant correlation between the total, emotional,
and functional scores and both the Beck Depression Inventory and the Modified
Somatic Perception Questionnaire. There was a strong correlation between the
THI and subjective symptom scales for annoyance, sleep, depression, and concentration.
The profile was normalized on a well-distributed mix of patients, including
those with primary tinnitus and tinnitus associated with hearing loss (see Table 2 for normative values). Test-retest
reliability was subsequently validated on a series of 29 patients with primary
tinnitus.5 Correlations between the test and
retest values ranged from 0.84 to 0.94. These desirable characteristics led
to the selection of this outcome measure for our investigation. A recent study
by Baguley et al17 examined the convergent
validity of the THI and the Tinnitus Questionnaire and concluded that that
these 2 questionnaires had good convergent validity of their total scores
but the THI subscores may not be as significant.
The THI total and subscale scores in our population were higher than
those obtained during initial THI development and during further validation
on a primary tinnitus population (Table
2). This was not entirely surprising, since one would expect that
a tinnitus and hyperacusis specialty center may attract a more profoundly
affected group of patients than those seen in a general audiology outpatient
clinic, from which the original normative values were derived.
AUDIOLOGY, THI SCORES, AND SUBJECTIVE TINNITUS CHARACTERISTICS IN PATIENTS
WITH PRIMARY TINNITUS
Initial audiologic data revealed normal PTAs and SDSs, confirming the
primary nature of the tinnitus in our population. There was no association
between severity of THI scores and PTA or SDS. Additionally, there were no
associations between loudness matching or minimum masking level and THI scores.
Thus, as previously demonstrated, the impact of tinnitus on a patient's well-being
appears to be independent of the psychoacoustical properties of the tinnitus.
Alternatively, there may be insufficient sensitivity of the THI to reflect
subtle changes in audiologic parameters.
THE EFFECT OF HYPERACUSIS
Our audiometric definition of hyperacusis is an LDL less than 100-dB
hearing loss. The average LDL in our baseline population was greater than
100-dB hearing loss. In contrast, 60% of our patients subjectively complained
of sound tolerance problems. The correlations between the subjective presence
of sound tolerance problems and higher THI total, emotional, and catastrophic
scores reiterate the significance of perceived disability in a primary tinnitus
population. The disparity in psychoacoustical and subjective assessment of
hyperacusis is consistent with previous studies1, 3 and
underscores the need for patient-based assessments.
PATIENT-BASED OUTCOMES FOLLOWING TRT
Tinnitus retraining therapy is a systematic clinical protocol that proposes
that both auditory and nonauditory centers are involved in clinically relevant
tinnitus. Positron emission tomography has been used to map tinnitus-specific
activity to auditory and prefrontal-temporal cortices as well as the limbic
system.18 According to this model, the brain
can be retrained to remove the negative emotional association given to the
tinnitus signal (habituation of the reaction). Decreasing the contrast between
the tinnitus signal and random background activity within the neural pathways
with low level, broadband sound further facilitates habituation (habituation
of perception). The goal of TRT is to remove the perception of tinnitus from
the patient's consciousness by initiating and facilitating the process of
habituation. The therapeutic efficacy of TRT has been challenged in the past
because of the lack of appropriate outcomes data.19-20
Our results reveal a significant improvement in THI total scores following
6 months of TRT counseling and the implementation of sound generator devices.
Although our sample size is small, every patient enrolled was followed up,
and changes in the THI total score were significant. These prospective results
thus suggest that TRT is effective in reducing some of the distressing effects
associated with tinnitus. Longer duration and larger multi-institutional studies
should be initiated to confirm this trend. The use of broadly validated patient-based
outcomes measures such as the THI will allow accurate comparisons between
patients and between institutions, which is a major limitation of other subjective,
nonvalidated surveys when absent. Furthermore, such an instrument allows for
the possibility of test-retest evaluation following TRT intervention. In conclusion,
TRT improves self-perceived disability induced by chronic tinnitus as reflected
by improved THI total score after 6 months of TRT.
AUTHOR INFORMATION
Accepted for publication March 21, 2002.
Corresponding author and reprints: Hinrich Staecker, MD, PhD, Otolaryngology–Head
and Neck Surgery, University of Maryland Medical System, 16 S Eutaw St, Suite
500, Baltimore, MD 21201-1619 (e-mail: hstaecker{at}smail.umaryland.edu).
From the Tinnitus and Hyperacusis Center, Division of Otolaryngology–Head
and Neck Surgery, Department of Surgery, University of Maryland Medical System,
Baltimore.
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