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What can we learn about auditory processing from adult hearing questionnaires?
Doris-Eva Bamiou,1,2 Vasiliki (Vivian) Iliadou 3, Sthella Zanchetta,4 and Chrysa Spyridakou.1,5
From:
1 Neuro-otology Department, National Hospital for Neurology and Neurosurgery, Queen Square
London
2 UCL Ear Institute, London
3 Medical School, Aristotle University of Thessaloniki, Greece
4 Depto of Ophthalmology, Otorhinolaryngology, and Head and Neck Surgery, School of Medi-
cine of Ribeirão Preto-University of São Paulo, Sao Paolo
5 Whittington Hospital, London
This is a copy of the final, accepted manuscript prior to copy editing by the journal’s edito-
rial staff. The published version of this manuscript is available at: http://www.ingentacon-
nect.com/content/aaa/jaaa/2015/00000026/00000010/art00004
J Am Acad Audiol. 2015 Nov-Dec;26(10):824-37. doi: 10.3766/jaaa.15009.
Correspondence to: Dr Doris-Eva Bamiou, Box 127 Neuro-otology Department, National Hos-
pital for Neurology and Neurosurgery, Queen Square London WC1N 3BG UK.
Email: d.bamiou@ucl.ac.uk Tel: +44 20 3448 3135 Fax: +44 20 3448 4775
Conflicts of interest: none
Source of funding: none
Structured abstract
Background: Questionnaires addressing auditory disability may identify and quantify patients’
specific symptoms in adults with listening difficulties.
Purpose: a. to assess validity of the Speech Spatial Qualities hearing scale (SSQ), the (Modified)
Amsterdam Inventory for Auditory Disability (mAIAD) and the Hyperacusis questionnaire
(HYP) in adult patients experiencing listening difficulties in the presence of a normal audiogram
b. to examine which individual questionnaire items give the worse scores in clinical subjects
with an auditory processing disorder (APD).
Research Design: A prospective correlational analysis study.
Study Sample: Clinical subjects (N=58) referred for assessment because of listening difficulties
in the presence of normal audiometric thresholds to Audiology/ENT or Audiovestibular Medi-
cine clinics. Normal control subjects (N=30).
Data Collection & Analysis: The modified Amsterdam Inventory for Auditory Disability (mA-
IAD), Hyperacusis (HYP) questionnaires and the Speech Spatial Qualities hearing scale (SSQ)
were administered to a clinical population of non-neurological adults who were referred for audi-
tory processing assessment because of hearing complaints in the presence of normal audiogram
and cochlear function and a sample of age matched normal hearing controls before auditory pro-
cessing testing. Clinical subjects with abnormal results in at least 1 ear, in at least two tests of
auditory processing (and at least one of these tests to be non-speech) were classified as clinical-
APD (N= 39), and the remaining (16 of whom had a single test abnormality) as clinical-non APD
(N=19).
Results: The SSQ correlated strongly both with the mAIAD and the HYP and correlation was
similar within the clinical group and the normal controls. All questionnaire total scores and sub-
scores (except sound distinction of mAIAD) were significantly worse in the clinical APD vs. the
normal group, while questionnaire total scores and most subscores indicated greater listening dif-
ficulties for the clinical non-APD vs. the normal subgroups. Overall, the clinical non-APD group
tended to give better scores than the APD in all questionnaires administered. Correlation was
strong for the worse ear gaps in noise threshold with the SSQ, mAIAD, and HYP, strong to mod-
erate for the speech in babble and left ear dichotic digit test scores (at p <0.01) and weak to mod-
erate for the remaining auditory processing tests except the frequency pattern test which did not
correlate. The worse scored items in all three questionnaires concerned speech in noise questions.
This is similar to worse scored items by hearing impaired subjects as reported in the literature.
Worse scored items of the clinical group also included quality aspects of listening questions from
the SSQ, that most likely pertain to cognitive aspects of listening, such as ability to ignore other
sounds and listening effort.
Conclusions. Hearing questionnaires may help assess symptoms of adults with APD. The listen-
ing difficulties and needs of adults with APD to some extent overlap with those of hearing im-
paired listeners, but there are significant differences. The correlation of the gaps-in-noise and du-
ration pattern (but not frequency pattern) tests with the questionnaire scores indicates that tempo-
ral processing deficits may play an important role in clinical presentation.
Keywords: auditory processing, questionnaires, hearing, auditory processing disorder, central
auditory processing disorder, gaps-in-noise
Abbreviations:
mAIAD: modified Amsterdam Inventory for Auditory Disability
HYP: Hyperacusis questionnaire
SSQ: Speech Spatial Qualities hearing scale
CAPD: Central Auditory Processing Disorder
APD: Auditory Processing Disorder
AAA: American Academy of Audiology
ASHA: American Speech & Hearing Association
ENT: Ear Nose & Throat physician
NHNN: National Hospital for Neurology and Neurosurgery
INTRODUCTION
Approx. 4% of working age adults (Hind et al, 2011) and up to 10% of all adults (Kumar et al.,
2007) who present to Audiology departments with complaints of significant listening difficulties
have normal pure tone thresholds. A proportion of these patients give abnormal performance on
complex psychoacoustic tests, and in the absence of a neurological lesion, their listening difficul-
ties are attributed to functional deficits in sound processing within the extended central auditory
nervous system (Moore et al, 2013). This clinical presentation is categorised as Auditory Pro-
cessing Disorder (APD, category H93.25 in ICD-10). However, the vast majority of these pa-
tients will be dismissed with no further testing beyond an audiogram and with no management
recommendations (Kumar et al, 2007). Yet, even adults with an early APD diagnosis since child-
hood continue to complain of significant auditory and related psychosocial difficulties in later
years (Del Zoppo et al, 2014).
Diagnosis of APD is based primarily on a behavioural psychoacoustic test battery evaluating dif-
ferent aspects of auditory processing (i.e. temporal processing, pitch discrimination, speech in
noise/babble perception, binaural integration). The diagnostic tests serve as tools that inform the
individualised management and intervention approach, by defining the nature and severity of the
auditory processing deficits and disorder (Bamiou et al, 2006; AAA, 2010). However, while tests
may establish the relationship between the acoustic signal and the subjective percept under labo-
ratory conditions, laboratory tests in general do not reflect the communication difficulties the pa-
tient is faced with in the everyday dynamic acoustic environment (Gatehouse and Noble, 2004).
Questionnaires addressing auditory disability may be used in addition to tests, in order to identify
and quantify patients’ specific symptoms in real life, guide diagnostic test choice and help in-
form choice of additional appropriate strategies and interventions that aim to either ameliorate
the auditory problem directly, or lessen its impact, on an individual basis (Bamiou et al, 2006;
Dillon et al, 2012).
There are a few paediatric questionnaire studies of APD (e.g., Iliadou and Bamiou, 2012), their
results, however, may not be directly extrapolated to adults with APD, particularly as there are
well documented age related changes in auditory processing and related skills. Questionnaires
specifically designed for APD in adults are lacking. In the absence of validated adult APD self
report measures, existing adult questionnaires that assess auditory performance and disability in
adults with peripheral hearing impairments may be of clinical value when assessing adults with
APD. This is because adults with a variety of APD presentations present with some similar com-
plaints to hearing impaired adults, for example with difficulties in speech in noise perception, or
localisation of sounds (Meijer et al, 2003; Noble and Gatehouse, 2006; Spyridakou et al, 2012;
Bamiou et al, 2012). Application of these questionnaires to the APD population may help identi-
fy patients’ symptoms in a more structured and validated manner and extend on the spontaneous
symptom report by the patient during clinical assessment and history taking.
In the present study we chose to include two questionnaires validated on hearing impaired adults,
the modified Amsterdam Inventory for Auditory Disability (mAIAD), and the Speech Spatial
Qualities hearing scale (SSQ). This choice was driven by three factors: i. Both mAIAD and SSQ
questionnaires contained several questions for speech in noise hearing, which is the main reason
for referral to our adult APD clinic ii. Both questionnaires had been previously used in other clin-
ical populations with normal audiometric thresholds and/or auditory processing deficits, and had
demonstrated differences between a normal and clinical groups (Neijenhuis et al, 2003; Bamiou
et al, 2012; Banh and Pichora-Fuller, 2012) and iii. Published questionnaire results of hearing
impaired populations were available for comparison with the present study’s clinical group.
The mAIAD (Kramer et al, 1995; Meijer et al, 2003) assesses the patient’s auditory performance
in typical communication situations with regards to speech intelligibility in noise and in quiet,
auditory localisation skills, recognition and detection of sound abilities. The mAIAD has been
used in a few studies of adults with APD. Neijenhuis et al (2003) assessed hearing disability in
24 otherwise neurologically normal adults with a suspected auditory processing disorder, i.e. pa-
tients who complained of hearing difficulties despite the presence of a normal audiogram and
speech in quiet audiometry, as part of a validation study for a central auditory test battery. 68% of
these adults gave abnormal results (scores below the 90th percentile of the normal control group)
in the central auditory test battery. Neijenhuis et al found that, as a group, the subjects with an
auditory processing disorder reported significantly more complaints regarding hearing abilities
than normal controls for all five factors assessed by the Amsterdam Inventory, with speech in
noise and sound localization as the most frequently reported difficulties. In a pilot study of 10
adult subjects with developmental APD and 12 normal controls (Spyridakou et al, 2012), that
used the mAIAD in addition to a hyperacusis questionnaire that was developed in order to quan-
tify auditory hypersensitivity (Khalfa et al, 2002), significant differences in all mAIAD and hy-
peracusis scores were reported between the two groups, while the questionnaire scores correlated
with speech in babble and TEOAE suppression test results. The mAIAD was further adminis-
tered in a study of 21 adults with stroke of the auditory brain and 23 normal age and hearing
matched controls (Bamiou et al, 2012). The study found significant differences in sound localisa-
tion and recognition between the two groups, and again questionnaire scores correlated with di-
chotic digits and pattern test results.
The SSQ evaluates auditory disability in real life complex listening situations. It was designed in
order to assess “more complex and dynamic aspects of hearing capacity”, and informed by audi-
tory scene analysis principles (Gatehouse and Noble, 2004). It has been widely used in hearing
loss patients (Noble and Gatehouse, 2006; Douglas et al 2007; Tyler et al, 2009; Potts et al, 2009;
Martin et al, 2010) but it has also been found to be as effective in comparing younger and older
adults with normal hearing thresholds at least up to and including 3000Hz (Banh and Pichora-
Fuller, 2012).
A third questionnaire that was included in the present study was chosen in view of our previous
findings that adults with Auditory Processing Disorder report symptoms of hyperacusis (Spyri-
dakou et al, 2012), our own anecdotal observations that (non-autistic) children with APD fre-
quently report hypersensitivity to some loud sounds, and reports that the majority of patients ex-
periencing hyperacusis have normal pure tone audiometric thresholds (Brandy and Lynn, 1995).
On this basis we decided to include a hyperacusis (HYP) questionnaire (Khalfa et al, 2002) that
has been validated in the general population. . The HYP quantifies and characterises the clinical
phenomenon of hyperacusis over the emotional, social and attentional dimensions and it provides
a cut-off score for clinically significant hyperacusis.
The present study aimed to evaluate and characterise listening skills and difficulties measured
through these three questionnaires (mAIAD, hyperacusis and SSQ) in a clinical group of non-
neurological adults who were referred for auditory processing assessment because of hearing
complaints in the presence of normal audiogram, vs a sample of age matched normal controls.
Comparison of scores of all three administered questionnaires between the clinical and the nor-
mal controls was conducted to assess whether the questionnaires can separate the clinical sub-
groups vs. the normal group. We also assessed whether performance on the three instruments
was correlated. As SSQ is the most widely used for auditory disability (Gatehouse and Noble,
2004), the other two questionnaires were compared against it.
A secondary aim was to explore criterion validity, by correlating questionnaire scores with an-
other measure that is well established and accepted in the field (Garson, 2013). Since there is no
gold standard for auditory processing tests, currently used clinical tests of auditory processing,
from test categories proposed by ASHA (2005) and American Academy of Audiology (2010)
were used for this purpose and an exploratory criterion validity assessment was performed by
assessing correlation of the questionnaire scores with the diagnostic auditory processing test re-
sults.
Finally, we examined which individual items in the three questionnaires gave the worse scores
(indicating greater levels of difficulty) in the clinical population and whether these differed from
the worse scored items by the hearing impaired population as reported in the literature. This was
done in order to gain some initial understanding of listening aspects that may separate the APD
from the hearing impaired client group, but also to inform future content validation of other
questionnaires, specifically developed to assess this population which will need to incorporate all
facets of the construct of auditory processing related listening skills (Cronbach and Meel, 1955).
We hypothesised that there is a good correlation between the different questionnaire instru-
ments and also correlation between auditory symptoms as reported by SSQ, MAIAD, hyperacu-
sis instruments and speech & non-speech based auditory processing tests.
MATERIAL AND METHODS
Patient recruitment
Ethics approval was obtained from the National Research Ethics Committee of the National
Hospital for Neurology and Neurosurgery (NHNN) (Registration number 09/H0716/ 46). All re-
cruited subjects gave informed signed consent. We recruited clinical subjects who were referred
for assessment because of listening difficulties in the presence of normal audiometric thresholds
to the audiology/ENT or audiovestibular medicine clinics at the Whittington, Royal National
Throat Nose & Ear Hospital and the National Hospital for Neurology Neurosurgery.
Inclusion criteria were: English as first language, age 18-60 years old, normal hearing on pure
tone audiometry (thresholds ≤ 20dB bilaterally at octave frequencies of 0.5-8kHz), past history
of schooling within mainstream education and absence of a prior history of neurological disorder.
Exclusion criteria were psychiatric or cognitive disorder previously diagnosed or identified dur-
ing the clinical interview or history of head injury, stroke, or other neurological disorder.
Normal control subjects were recruited from all grades of hospital staff, students, and patient
friends with the same inclusion and exclusion criteria as for patient subjects and no listening dif-
ficulties complaints.
Test protocol
After consent, a medical history was obtained for otological and audiological problems, medical,
family and social history, followed by clinical otoscopy.
Questionnaires
Subjects were given three validated questionnaires to complete prior to auditory processing as-
sessment:
a.The modified Amsterdam Inventory for Auditory Disability-mAIAD (Kramer et al, 1995;
Meijer et al, 2003) that consists of 28 questions that assess five domains: speech intelligibil-
ity in noise - SiN (question numbers: 7 ,24,18,1,13), speech intelligibility in quiet- SiQ
( question numbers : 14 ,19 ,11, 12, 8) auditory localization- Loc (question numbers: 15 ,3 ,
26 ,20 ,9 ), distinction/recognition of sound - Dist (4, 5, 6, 17, 22, 23, 25,28), detection of
sound- Det (question number: 27,16,21,2,10). Questions were scored on a 4 point response
scale ranging from almost never (indicating greatest difficulty and scored 0 point), occa-
sionally (1 point), frequently (2 points), almost always (indicating least difficulty and
scored 3 points). Subscores and total score were calculated as the average of total scores for
each subscale and for the entire inventory.
b.The 14 item Hyperacusis Questionnaire - HYP (Khalfa et al, 2002) assesses attentional,
social and emotional aspects of hyperacusis on a 4 point scale ranging from no symptoms (0
points) to a lot of symptoms (3 points). A total score was calculated by adding up the re-
sponses. Scores over 28 indicate clinically significant hyperacusis.
c.The Speech, Spatial and Qualities of Hearing Scale (SSQ) (Gatehouse and Noble 2004)
has 50 items and consists of 3 sections: speech (questions 1- 14), spatial (questions 1-17)
and qualities of hearing (questions1-19) with the third section referring to qualities of sound
segregation and identification, and other characteristics of hearing experience. The scoring
system uses the ruler representation from 0 (complete inability) to 10 (greater ability).
Scores for each subscale and for the entire SSQ were calculated as averages of the respons-
es.
Test battery
During the next step all subjects had the following tests in a single test session (with breaks in
between). Tests were conducted in a sound treated booth and with calibrated equipment:
Standard pure tone audiometry (British Society of Audiology-BSA 2011) was conducted at
octave levels across 250 to 8000 Hz with a GSI 61 audiometer with TDH -50 earphones (Grason-
Stadler, Guymark Uk Limited, Veronica House West Midlands UK) .
Tympanometry (BSA 1992) was obtained with a 226 Hz probe signal maintained at 85dB SPL
in the sealed ear canal using a GSI-33 Middle Ear Analyser (Grason-Stadler, Guymark Uk Lim-
ited, Veronica House West Midlands UK). Normal results were middle ear pressure >/= 150
mmH2O and compliance > 0.3cc.
Transient Evoked Otoacoustic Emissions -TEOAEs (Kemp et al. 1992) were conducted with
the ILO 88/92 Otodynamic Analyser system (Otodynamics Ltd, Hatfield, Hertfordshire UK).
Click stimuli with a 50/s repetition rate and 80db SPL peak reception level were delivered via a
probe in the ear canal. The inner ear responses were recorded automatically over 20 ms post
stimulus recording time and FFT spectrum analysis and average waveform were calculated au-
tomatically. A normal response was overall TEOAE amplitude ≥ 6 dB in at least three adjacent
frequency bands.
Central Auditory Processing tests (AP tests) were chosen on the basis of recommendations by
the American Academy of Audiology (AAA, 2010) and the British Society of Audiology (BSA,
2011) to include both speech and non-speech, behavioural and objective tests that tap into differ-
ent auditory processes. Tests included:
The Speech in babble test (SiB). This is a low redundancy speech in babble type noise test. The
SiB is presented on a calibrated computer using Matlab software (MathWorks, Cambridge UK)
with Sennheiser headphones (Sennheiser UK, Marlow, Buckinghamshire, UK). There are 8 in
total phonemically and phonetically balanced word lists, recorded by a female native Southern-
English speaker with a Received Pronunciation (RP) accent, that contain a total of 230 words
that are equally easy/hard to recognise, compiled from an already existing database from the de-
partment of phonetics and linguistics (University College of London) (Kalikow et al, 1977; Brad-
low and Pisoni, 1999). The words are presented in the background of a 20-talker babble noise,
derived from the UCH/Middlesex Hospital Video LaserDisc 1993: IHR babble.wff(.wav) sam-
pled 23-May-96: 22.05 kHz, 16-bit file (66 dB(A) RMS sample values): 15s. This babble is
mixed from recordings of twenty different talkers at approximately equal levels. Two randomly
selected monosyllabic consonant vowel consonant word lists in a background of multi-talker
babble are presented to each ear (i.e. each ear is tested twice). The signal to noise ratio during the
test is varied adaptively. A threshold value is obtained, calculated by the Matlab software as the
mean signal to noise ratio of 70.7% correct performance criteria (2:1 rule) from the final (six to
eight) reversals. An extended normative data study revised the cut off mean value for both ears at
4.4 dB signal to noise ratio.
The remaining central auditory processing tests were recorded on a compact disc that was played
on a Sony XE 270 CD player (Sony Europe Limited, The Heights, Brooklands, Weybridge UK)
and routed via the GSI 61 diagnostic audiometer to TDH-50 earphones. The stimuli were pre-
sented at 50 dB sensation level relative to the pure tone audiometry 500-1000 Hz average pre-
sented to each ear independently. A brief practice session preceded each test. Tests included a
dichotic speech (dichotic double digits) (Musiek 1983; Musiek et al, 1991), temporal pattern
(frequency and duration pattern) tests (Musiek and Pinheiro 1987; Musiek et al, 1990) and tem-
poral resolution (gaps in noise) (Musiek et al, 2005). (All CDs provided courtesy of Professor
Musiek).
The Dichotic Digits test (DDT) (Musiek 1983; Musiek et al, 1991). The test is composed of nat-
urally spoken single digits from 1 to 9, excluding 7. A different pair of digits is given simultane-
ously to each ear and the listener has to repeat all four digits. The outcome measure is the per-
centage of correct responses for each ear. Normal scores are 90% or better for each ear (R DDT-
right ear results, L DDT- left ear results) (Musiek et al, 1991). After a brief practice session, the
listeners were administered a list of 40 paired digits in each ear.
Frequency pattern test (FPT) (Musiek and Pinheiro 1987). The test stimuli consist of 3 tone
burst sequences, which are a combination of low (880 Hz) and high frequency (1122Hz) tones at
300 ms inter-stimulus intervals. Each sequence is composed of two bursts of the same and one
burst of a different frequency. The listener is required to name the sequence (e.g, high-high-low).
The outcome measure is the percentage of correct responses. Normal scores are 80% or better. A
total of 20 patterns were presented monaurally to each ear.
Duration pattern test (DPT) (Musiek et al, 1990). The test stimuli consist of 3 tone burst se-
quences, which are a combination of long (500 ms) and brief duration (250 ms) tones of 1000
Hz. Each sequence is composed of two bursts of the same and one burst of a different duration at
300 ms inter-stimulus intervals. The listener is required to name the sequence (e.g, short-long-
short). The outcome measure is the percentage of correct responses. Normal scores are 70% cor-
rect or better. A total of 20 patterns were presented monaurally to each ear.
Gaps in Noise test (GIN) (Musiek et al, 2005). In this test the patient is monaurally presented
with a 6 second burst of white noise in which 0 - 3 gaps of varying duration (2ms to 20ms) are
embedded. The patient has to identify the number of gaps in each noise burst. This test provides
two scores, the correct detection score (percent of correct answers) and the gap detection thresh-
old, which is defined as the shortest gap duration that the patient can correctly identify in 50% of
the trials (i.e., in 3 out of 6 trials for each gap duration). Normal results are a threshold of 6 ms or
better and a correct score of 50% or better (from our own normative data collected from 40 nor-
mal adults aged 20-55 years).
Suppression of TEOAEs by contralateral noise - SUPP (Ceranic et al, 1998; Spyridakou et al,
2012) was conducted as a potential “objective” index for speech in noise abnormalities, and/or
hyperacusis, since human studies have proposed that the suppression effect, thought to be medi-
ated via the medial olivocochlear bundle, may enhance speech intelligibility in the presence of
background noise (Kumar and Vanaja, 2004; Brown et al., 2010), while abnormal suppression
correlated with hyperacusis reports in a traumatic brain injury population (Ceranic et al, 1998).
SUPP was conducted on the ILO 88/92 Otodynamic Analyser System using an evoking click
with and without suppressive contralateral noise. A SUPP value is calculated by subtracting
TEOAEs response in noise from TEOAE response in quiet, and a value equal to or greater than
1dB is taken as normal.
Classification of clinical subjects: Clinical subjects with abnormal results in at least 1 ear, in at
least two tests of auditory processing (AND at least one of these tests to be non-speech) were
classified as clinical-APD (American Academy of Audiology, 2010), while the remaining pa-
tients as clinical-non APD.
Statistical analysis
The IBM Statistical Package for the Social Sciences –SPSS program version 22 (Armonk, NY:
IBM Corp) was used. Regression was conducted between the questionnaires (with the SSQ as
independent variable) to assess validity, while non-parametric testing (independent samples
Kruskal-Wallis tests) were conducted to assess differences between the clinical APD, the clinical
non-APD and normal control groups. A Spearman rho cross tabulation was conducted with ques-
tionnaire total scores with worse ear auditory processing test results. Finally, the 6 individual
items (or more if scores were equal) with the worse scores in the mAIAD, SSQ and HYP ques-
tionnaires were identified for each subgroup and tabulated against worse scored items reported in
the literature for hearing impaired adults when such data were available.
RESULTS
Participant characteristics.
58 clinical and 30 control subjects were recruited and tested. All had normal audiometric thresh-
olds, tympanograms and TEOAEs. 39 of the clinical subjects were classified as clinical –APD
(see "Classification of clinical subjects" for criteria used). The remaining clinical subjects had a
single test abnormality in one or both ears and were classified as clinical - non APD. Normal
control subjects all gave normal auditory processing test results. Age and gender of clinical and
normal control subjects are summarised in table 1.
Clinical vs non clinical groups.
Table 2 summarises questionnaire results in the study groups. All scores were significantly worse
in the clinical APD group, followed by the Clinical non-APD group and significantly better
scores were found in the normal control group p<0.001 for all variables with the exception of
distinction/recognition of sound of the mAIAD where significance was at p<0.01. Eleven (out of
56) clinical subjects (8 with APD) had a clinically significant score of >28 for hyperacusis (Khal-
fa et al, 2012), while all controls gave normal scores.
Correlation between questionnaires.
As the clinical non-APD group (in which participants had 1 APD test abnormality only) showed
significant differences from the normal group on all three questionnaires, and in view of the
presence of several different set of diagnostic criteria for APD, for purposes of correlation analy-
sis, subjects of the clinical non-APD and the clinical APD group were grouped together as the
clinical group.
The mAIAD correlated with the SSQ with Spearman Rho .745 at p <0.001 (see figure 1). The
HYP correlated with the SSQ with Spearman Rho = -.712 at p<0.001 (see figure 2). For both
correlations, it was not solely the clinical or the normal group that drove the correlation (see fig-
ures 1 and 2).
Criterion validity: cross tabulation of questionnaire scores with auditory processing test
results.
All individual Central Auditory Processing Tests showed statistically significant correlations
with overall scores of each of the three questionnaires on listening difficulties. There was a
strong relationship between the GIN worse score and all three questionnaires and slightly less so
with the worse ear SiB and left ear DDT (table 3).
Additional analysis: FPT correlation with single questionnaire items.
The only central auditory processing test that did not show any significance with each of the
three questionnaires was the Frequency Pattern Test (FPT). Additional analysis with Spearman's
rho of individual mAIAD items that may be linked with frequency discrimination abilities (items
mAIAD6, 22, 25, 28, and SSQ quality5, 7) were conducted. While these items strongly corre-
lated with each other at the 0.01 p level and with Spearman rho exceeding .5, the worse ear FPT
weakly correlated at the 0.05 level with mAIAD 6 (can you recognize melodies?), SSQ quality 5
(do you find it easy to distinguish different pieces of music?) and 7 (when you listen to music,
can you make out which instruments are playing?).
Individual items with lowest scores and comparison with hearing impaired published data
The 6 questions with the worse average scores were identified for the mAIAD (table 4) and SSQ
(table 5) for the study groups and are presented against such scores reported for hearing impaired
subjects (recalculated for the mAIAD from Hallberg et al, 2008).
From these two tables, the single items that yielded a worse mean average score in the clinical
APD group than in the hearing impaired group was the SSQ quality item 19: “Can you easily
ignore other sounds when trying to listen to something?” (Gatehouse and Noble, 2004) with
mean 3.4, SD 2.6 in the APD vs. mean 5.3 SD 3.1 in the hearing impaired group, and a statisti-
cally significant difference between the two groups at p= 0.001.
The worse scored items from the Hyperacusis questionnaire for the total clinical group and clini-
cal subgroups are presented in table 6. The worst scored item for the entire clinical group was
“listening to conversations in noise”.
DISCUSSION
This study sought to assess the clinical presentation of APD in a non-neurological adult popula-
tion with reported listening difficulties in the presence of normal audiogram and cochlear func-
tion vs. normal controls. The clinical APD group gave significantly worse scores than the normal
group in all questionnaires and subscales (except distinction of sounds of mAIAD). Speech in
noise was a greater concern than speech in quiet on the mAIAD, and listening to speech was a
greater concern than localisation of sounds in both mAIAD and SSQ, similar to other studies in a
variety of populations with APD (Blaettner et al, 1989; Neijenhuis et al, 2003; Spyridakou et al,
2012; Bamiou et al, 2013). From the 56 clinical subjects, 8 with diagnosed APD and 3 without
had a clinically significant score hyperacusis, without clinically significant tinnitus. They were
dully sent to hearing therapy for management of their symptoms (by means of counselling, sound
therapy and/or other practical advice as appropriate on a case by case basis). Hyperacusis is at-
tributed to an increased central response gain in subcortical brain regions that compensates for
the reduced sensory input in the presence of peripheral auditory damage (Knipper et al., 2013). It
may also occur due to pathological intensity encoding at later stages of auditory processing be-
yond the auditory cortex, in the presence of neurological lesions (Boucher et al, 2015). The clini-
cal subjects with hyperacusis did not have any overt peripheral auditory deficits. Their report of
hypersensitivity to loud sounds may be a behavioural marker for impaired intensity processing at
higher stages of the auditory pathway.
Overall, the clinical non APD group (who had 1 AP test abnormality) was broadly similar with
the clinical APD group (who had at least 2 test abnormalities), but slightly less impaired on the
basis of the questionnaire scores, indicating that there is a continuum for APD, as others have
suggested (Phillips et al, 2010). The diagnostic yield for APD varies widely depending on which
set of criteria are being used, as there is no consensus on diagnostic criteria (Wilson and Arnott,
2013). Dillon et al (2012) argue that even a single test abnormality or comparatively low perfor-
mance in the presence of listening difficulties consistent with this abnormality would be a mean-
ingful finding when a predetermined test battery is being used. We would thus argue that a clini-
cal subject with a single test abnormality as well as abnormal scores on these validated hearing
questionnaires ought to receive appropriate intervention, that should be decided on the basis of
both questionnaire and test results. In subjects with significant disability on the questionnaires
but normal AP test results cognitive/psychological factors ought to be considered and excluded,
however in the absence of any overt cognitive/psychological problems, and when it is not possi-
ble to further investigate with additional AP test tailored to the patients symptoms (Griffiths et al,
2010) management e.g. with listening strategies would be of benefit.
The strongest correlations observed between the questionnaires and AP tests were with the non-
speech threshold estimation gaps in noise test, the consonant-vowel-consonant word in babble
test, and the dichotic digits left ear score. The GIN (Musiek et al, 2005) is a relatively newer test,
with lesser cognitive demands than other tests of the APD clinical test battery, in that the respon-
dent is asked to press a button rather than produce an oral response, and is not required to re-
member the sound sequence. Additionally it allows threshold estimation by providing six trials
for each gap duration and may be assessing a more sensory processing element than other tempo-
ral tests (Iliadou et al, 2014). Temporal processing has consistently emerged as a single factor
(for temporal sequencing tasks, Domitz and Schow, 2000) or combined factor (for masking tasks,
Ahmmed et al 2012) in paediatric factor analysis studies that investigate what are the key audito-
ry and/or non-auditory factors that underpin auditory behavioural test performance. Temporal
processing ability correlates well with laboratory speech in noise test performance in adult sub-
jects (Helfer and Vargo, 2009), and a modest correlation between the SiB and GIN was similarly
observed in our study. The GIN thus appears efficient in tapping into real life patient reported
listening difficulties and may index a low level auditory (temporal) processing component to ac-
count for subject speech in noise deficits and reported symptoms.
Of interest, there was a dissociation between FPT and DPT correlation with questionnaire scores,
in that DPT showed modest correlation, while FPT didn’t. A separate correlation was between
the FPT and single questionnaire items that were expected to depend on skills important for this
test. This showed that the FPT correlated only at the 0.05 level with mAIAD 6 (can you recog-
nize melodies?), SSQ quality 5 (do you find it easy to distinguish different pieces of music?) and
SSQ quality 7 (when you listen to music, can you make out which instruments are playing?). In
paediatric studies, temporal ordering as indexed by the FPT emerges as 1 out of 4 factors ac-
counting for the APD presentation (Domitz and Schow 2000). However, in normal developing 11
year old children, the unique residual variance explained by sequence analysis, irrespective of IQ
and after accounting for shared variance, is only 4% for sequencing in pitch domain and 6% in
the time domain (Grube et al, 2012). In view of these studies, it would be expected that both
DPT and FPT would show some modest correlations with the patient reported symptoms. The
dissociation in DPT and FPT results might indicate that, in this adult population, temporal pro-
cessing is more relevant for good listening skills than pitch processing, since the only difference
between DPT and FPT is the need to differentiate between duration vs. frequency of the tones
that constitute the sequence. This would also fit with the finding of a strong questionnaire corre-
lation with GIN, and with studies that show duration discrimination and the ability to make use
of rhythmic cues to decrease with age (Fitzgibbons and Gordon-Salant, 1995).
The dichotic test left ear score may tap into cognitive aspects of listening including memory and
attention (Hugdahl et al, 2009; Ahmmed et al, 2014). Recent neuroimaging studies show differ-
ences in frontal eye field activation (and thus in attentional bias) in children with right vs left ear
advantage in dichotic word tests, as well as diffusion tensor imaging findings indicating either
enhanced efferent or potentially decreased afferent connectivity of the frontal eye field with sub-
cortical regions, which could underpin the ear advantage finding at a sensory processing level
(Schmithorst et al, 2014). The finding of a moderate correlation of the left DDT with all three
questionnaire instruments would indicate that it may serve as a functional measure of listening,
that incorporates both attentional and sensory aspects of listening. The finding that the only ques-
tionnaire item in which APD subjects scored worse than hearing impaired subjects (as reported in
the literature) was the SSQ quality item asking how well they could ignore sound when listening
to something else would indicate that conducting the DDT by focusing attention to a single ear
response mode might be more appropriate for this population.
In terms of individual questionnaire items, the (quality aspect) ability to ignore other sounds, was
the only item with a significantly worse score in the clinical APD group than the hearing im-
paired (Gatehouse and Noble, 2004) by more than 1 unit in a 10 point scale (p= 0.001). This was
rated as top third most difficult item by the total clinical group, but only rated 22nd most difficult
by the hearing impaired population. The worse scored items by APD clinical subjects were oth-
erwise similar to those of hearing impaired listeners (Gatehouse and Noble 2004; Hallberg et al,
2008) and included questions such as speech items 10, 12 and 14 of the SSQ that address divided
and/or rapidly shifting attention. Scores in these items in the APD group were slightly better to
those of unaided hearing impaired listeners, but only by less than 1 unit in a 10 point scale for the
SSQ. Other worse scored items also included other quality aspects of listening from the SSQ,
that most likely pertain to cognitive aspects of listening, such as listening effort and concentra-
tion. The worst scored hyperacusis questionnaire items for the entire clinical group similarly in-
cluded items that could relate to cognitive effort/ cognitive load by noise (items 4, 12, 3). Imag-
ing studies indicate that listening to speech in noise test performance correlates strongly with ac-
tivation of frontal “cognitive” brain networks, in addition to primary auditory cortex, across the
age span (Wong et al, 2009; Schmithorst et al, 2011). Such activation of cognitive brain networks
is thought to be a compensatory mechanism for poor sensory processing (Wong et al, 2010).
However, cognitive loading may also disrupt sensory processing and encoding. Task-irrelevant
auditory input may engage attentional resources in older adults and result in unsuccesful sensory
encoding in the visual domain (Stevens 2008) while dual visual-auditory tasking may similarly
impair auditory perception (Mattys, Palmer 2015). A high concern for cognitive related aspects
of listening in the APD group could thus reflect a greater demand placed on cognitive resources,
because of degraded sensory auditory processing. Alternatively, it may reflect a greater vulnera-
bility of this population for attention engaging by task irrelevant stumuli, resulting in or con-
tributing to this clinical presentation. In our experience, patients who present to the APD clinic
report additional cognitive type listening concerns (e.g. regarding selective attention, working
memory or dual tasking) that are not addressed by existing questionnaires developed for hearing
impaired patients. Our study’s findings together with our (anecdotal) observations indicate that
cognitive aspects of listening should be explored further by additional questions in any future
adult APD questionnaire, while it would be of interest to assess how adult patient reported listen-
ing difficulties correlate with cognitive assessment scores, to understand better this clinical pre-
sentation.!
What are potential implications of our findings for clinical practice? Firstly, these questionnaires,
in addition to a (normal) audiogram may help reliably identify adults with suspected APD who
require further assessment before type of intervention is decided. They may also identify the
specific patient difficulties in real life contexts and thus supplement the diagnostic evaluation
process and help inform management. An intriguing question is whether documentation of listen-
ing difficulties on questionnaires would suffice to guide some limited at least management. Dil-
lon et al (2012) argues that real-life listening difficulties, in the presence of a normal audiogram,
can be addressed by nonspecific management advice such as preferential sitting or frequency
modulation systems, regardless if the cause for this presentation is or isn’t APD. This argument is
made in an attempt to remind that clinical practice calls for management decisions, regardless of
unresolved issues between the exact link between central auditory processing and attention/cog-
nition. Indeed, there is a growing body of evidence to indicate that a bottom up remote micro-
phone hearing aid (RMHA) provision intervention ameliorates patient/observer reported listen-
ing disability but also non-auditory symptoms and behaviours in a range of clinical populations
(Johnston et al 2009; Rance et al 2010; Schafer et al 2013). The SSQ and mAIAD could thus po-
tentially be used to identify adults who would benefit by simple interventions such as listening
strategies provision and to measure outcome. However, a proper study ought to assess whether
provision of an RMHA system could be decided solely on the basis of listening questionnaire
results: would RMHA systems successfully redress patient reported listening difficulties of indi-
viduals with normal results on speech in noise and other AP tests, or would these individuals
benefit more by other means of treatment such as counselling? For the purposes of choosing dis-
order (or deficit) specific driven remediation, further assessment would be required (Bamiou et
al, 2006; Dillon et al, 2012), in order to decide the need for analytic (ie targeting bottom-up sen-
sory processing) and/or synthetic auditory training (ie targeting top-down linguistic and other
higher order functions), as classified by Sweetow and Palmer (2005). For example, a worse
baseline speech in noise test performance predicts better training outcome (Song et al, 2011), jus-
tifying the need to recommend such training to those who fail speech in noise tests. While ques-
tionnaires may not suffice to inform choice of these specific forms of remediation, they may help
assess outcome, in terms of real life listening benefits. In addition, they may help decide whether
auditory perceptual or cognitive improvements drive the listening benefits by correlating im-
proved listening scores with improvement in different disorder specific tasks.
In conclusion, hearing questionnaires are a necessary adjunct for the assessment of adults with
suspected APD. This study shows that they can successfully separate adults with APD from nor-
mal controls. Administering these questionnaires following different interventions and manage-
ment may provide more data on correlation with evaluation of auditory processing; overcoming
possible limitations of the present study. The profile of APD adults may to some extent be sepa-
rated from those with hearing impairment. The correlation of the majority of central auditory
processing tests with overall score results of SSQ, mAIAD and HYP questionnaires shows that
auditory processing psychoacoustical tests and questionnaires on listening difficulties measure
the same elements. The correlation of a relatively low level task such as the gaps-in-noise with
the questionnaire scores together with the dissociated findings of DPT, but not FPT correlation,
with questionnaire scores may indicate that temporal processing deficits play a significant part in
this clinical presentation. Questionnaire evaluation may thus help inform evaluation adding to a
better understanding of the disability experienced.
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List of figures
Figure 1. Scatterplot of mAIAD total score vs. SSQ total score in the normal and clinical study
groups.
Figure 2. Scatterplot of Hyperacusis total score vs. SSQ total score in the normal and clinical
study groups.
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