Key Words auditory processing disorder - children - duration pattern test - pitch pattern test
INTRODUCTION
Children attending audiology clinics with reports of listening difficulties who are
found to have normal audiograms may be evaluated for an auditory processing disorder
(APD). The evaluation typically includes tests for auditory pattern recognition and
temporal processing ([ASHA, 2005 ]; [AAA, 2010 ]). Among the most common of these are variants of the pitch pattern sequence (PPS)
and duration pattern sequence (DPS) tests ([Emanuel et al, 2011 ]), consisting of sequences of three tones, one of which differs in frequency or duration
from the others ([Musiek, 1994 ]). Originally developed as tests for the auditory consequences of brain lesions ([Musiek and Pinheiro, 1987 ]; [Musiek et al, 1990 ]), PPS and DPS tests have been categorized as tests of temporal processing ([McDermott et al, 2016 ]). However, the long base duration of the tones (e.g., 500 msec), the easily discriminable
frequency (e.g., 0.5 octaves) and duration (e.g., 250 msec) differences, and the task
requirement to reproduce the correct ordering of the tones make them more appropriately
called tests of auditory pattern perception. The perception of auditory patterns is
influenced by the acoustic properties of the stimulus and by attention, working memory,
and experience ([Bregman, 1990 ]; [Alain and Woods, 1997 ]). Experience includes formal instruction (e.g., music lessons, [Kraus and Chandrasekaran, 2010 ]), statistical learning ([Skoe et al, 2015 ]), and informal sources (e.g., language exposure, [Zhang et al, 2005 ]; reading, [Walker et al, 2006 ]).
Performance of children on the PPS and DPS tests is strongly affected by the order,
timing, and number of stimuli, as well as how the sequences are presented (e.g., continuous,
discontinuous) and the type of response required ([Shin, 2003 ]). Regarding the response, a current clinical recommendation and practice ([Musiek, 2002 ]) is that a child should be asked to label the stimuli, either verbally or manually
(e.g., mouse, keypad), by pitch (e.g., high-low-low) or duration (e.g., long-short-long).
If this is not possible, the child should be encouraged alternatively to hum or gesture
the sound of the stimuli ([Musiek et al, 1994 ]; [Musiek, 2002 ]; [Weihing et al, 2015 ]; [Chermak et al, 2017 ]). It may be that labeling the stimuli involves an additional step that adds a greater
cognitive demand to the task. Both tasks share several steps including perception,
storage in and read out from working memory, and vocalic motor coding. For labeling,
an additional step of decision-making, preceding motor coding, may be necessary to
categorize the auditory stimuli (e.g., high/low pitch). Alternately, the commonly
reported co-occurrence of APD with language impairment (e.g., [Ferguson et al, 2011 ]) may limit the ability of those with lesions or delayed development to articulate
a verbal response.
Whatever the mechanism, we currently know of no experimental data comparing the influence
of response mode on test outcome for the PPS and DPS. The primary aim of this study
was to provide those data. If humming is to be used as a substitute for labeling,
the results of these two response tasks should be equal. Based on existing reports
and the aforementioned analysis, however, we hypothesized that humming would produce
superior performance. A secondary aim was to provide additional normative data on
both tests.
METHODS
Participants
Children were recruited from three primary public schools in the State of São Paulo,
Brazil, over 2 years. The children and their parents attended the Clinic School of
Speech and Hearing Therapy at Bandeirante University of São Paulo for three assessment
sessions, each of 1 hour duration and with a maximum interval of 1 week between the
sessions ([Table 1 ]). A total 452 children were assessed of whom 201 (44%; 97 girls and 104 boys) were
excluded and 23 (5%) withdrew. Of the remaining 228 children, 211 (PPS) and 198 (DPS)
completed one or both tests. Those not completing both tests had difficulty understanding
and/or performing the tasks. Approximately equal numbers of boys and girls of each
age contributed data ([Figure 1 ]).
Table 1
Schedule of Assessment Sessions and Order of Testing
First Session
Second Session
Third Session
Parent questionnaire (10)
PPS – Humming, Right (8)[* ]
DPS – Pointing, Right (7)[* ]
General behavior, speech (15)
PPS – Humming, Left (6)
DPS – Pointing, Left (5)
Pure tone audiometry (15)
PPS – Labeling, Right (8)[* ]
DPS – Labeling, Right (7)[* ]
Speech recognition quiet (5)
PPS – Labeling, Left (6)
DPS – Labeling, Left (5)
Acoustic immittance (10)
Note: Testing order was not counterbalanced. Approximate time taken for each element of
the battery is indicated (in minutes).
* Including 2-min practice.
Figure 1 Age and gender distribution of the children tested.
At Session 1, parents completed an extensive background questionnaire developed at
the Clinic. The 45-item questionnaire covered pregnancy history, general health, illnesses,
ear problems, developmental and educational history, and current abilities. All children
taking the PPS and DPS (see “Procedure”) were right handed, aged 7 years to 11 years
11 months (mean age = 9 years 4 months). Audiometric assessment and PPS and DPS testing
were conducted in a sound-attenuated booth. All children had normal hearing defined
as pure tone thresholds ≤15 dB HL at octave frequencies 250–8000 Hz and tympanograms
with peak compensated static acoustic compliance 0.4–1.6 mmhos and tympanometric peak
pressure of −100 to +50 daPa in both ears. They also had ≥92% word recognition performance
in each ear (in quiet, 40 dB above pure tone average threshold at 500, 1000, and 2000
Hz). In this test, the children repeated 25 monosyllabic words presented to each ear
open-set ([Russo and Santos, 2011 ]). Other inclusion criteria for the PPS and DPS testing were that all children spoke
Portuguese as their first and only language, and had no formal musical training or
any known language, learning, neurologic, psychiatric, or behavioral disorder, abnormal
pregnancy and/or perinatal history, or delayed neuropsychomotor or otologic history,
as determined through the parental questionnaire, completed during the first assessment
session ([Table 1 ]). [Figure 2 ] shows the proportion of children excluded for each reason.
Figure 2 Proportion of children excluded because of each criterion (see “Methods”). The total
number of exclusions was 201.
The same researcher/examiner (first author SAB) performed all these initial screens
and all the PPS and DPS evaluations. This researcher is a speech/language pathologist
and audiologist with experience in speech, language, and hearing assessment and central
auditory processing assessment. She also developed the instructions, applied the tests,
and judged and analyzed the responses. Use of a single researcher reduced variability
but did not enable an assessment of interrater reliability.
Procedure
Both PPS and DPS tests were presented from the Auditec Inc. audio DVD (Child Version,
6–9 years old, 1997) connected to an audiometer (Interacoustic AC40) using calibrated
TDH-39 circumaural headphones (ISO-398-1, ISO-398-8). For the PPS (Session 2, [Table 1 ]), 30 trials of three consecutive 500 msec duration high (1430 Hz) or low (880 Hz)
frequency tones with 300 msec interstimulus interval, 10 msec rise–fall time, were
presented monaurally at 50 dB HL. The interval between the trials was 10 sec. Six
different frequency patterns were presented ten times in random order, first to the
right then to the left ear: high-high-low, high-low-low, high-low-high, low-high-high,
low-high-low, and low-low-high. For the first 30 trials to each ear, the child was
asked to hum the sequence and for the next 30 trials, they provided verbal labels
(e.g., “high-low-high”). The examiner provided verbal instruction before each set
of test trials (humming, label) using, typically, two to three trials (but up to ten
trials) repeated by the child to ensure the child understood the task.
DPS (Session 3, [Table 1 ]) procedure was nearly identical to PPS. Each trial presented three 1000 Hz tones
of long (500 msec) or short (250 msec) duration. The interval between the tones was
300 msec, and the interval between the trials was 6 sec. The tones were combined in
six different patterns of duration: long-long-short, long-short-short, long-short-long,
short-long-long, short-long-short, and short-short-long. Initially, humming was tried
as a response mode for DPS, but children appeared to have difficulty with this task,
and the examiner also had difficulty judging their responses. For an alternative,
nonverbal response, the children instead indicated the duration pattern first by pointing
successively at short and long objects placed in front of them. After this pointing
response, the children provided a verbal label (e.g., “long-short-short”). To explain
these tasks, the examiner raised her fingers coinciding with the stimulus order and
explained the necessary response. Again, two to three practice trials were typically
delivered to confirm understanding of the task.
Order inversion, omission, and insertion of tones in the patterns were common incorrect
responses on both tasks ([Musiek, 1994 ]) and all response modes. As mentioned earlier, humming responses can be difficult
to perceive by the examiner, particularly by an inexperienced examiner and even in
the PPS. This point is taken up further in the “Discussion.”
The study was approved by the Research Ethics Committee of the Analysis of Research
Projects at the Hospital of the Clinics, Medical School, University of São Paulo.
Analysis
Descriptive statistics were used to summarize sample demographics and outcome measurements.
All scores of each child in both tests and ears and all response modes were calculated
by the number and percentage of correct answers. The difference between the test scores
and ear effect was checked by paired t -test or Wilcoxon signed-rank test based on whether the difference distribution was
approximately normally distributed.
For PPS humming scores, a two-part model including repeated measures was used to control
for a significant “ceiling” effect. In the first part, repeated measures analysis
using logistic regression was used to model the probability of a 100% score and, in
the second part, repeated measures analysis using generalized linear mixed models
(GLMM) was conducted to predict scores other than full scores (i.e., <100%). A log-normal
transformation on the test score was applied in the second part. PPS labeling, DPS
pointing, and DPS labeling scores were analyzed by repeated measures analysis using
GLMM by PROC GLIMMIX controlling for age and gender. The within-subject factor was
ear. The age was centralized at 7 years. The possible interaction effects were also
explored in all models.
Spearman rank order correlation was calculated to assess the relationships among the
test scores. Data were analyzed using SAS statistical software, version 9.3 (SAS Institute,
Cary, NC). A two-sided significance level was set at 0.05.
RESULTS
The highest scoring test was PPS humming, followed by PPS labeling, DPS pointing and
DPS labeling ([Figure 3 ]; [Table 2 ]). Significant ear differences were identified in all four tests, as indicated by
the linear regressions fitted to the data in [Figure 3B–D ] and the mean data in [Table 2 ]. For PPS humming ([Figure 3A ]), the left ear score was slightly higher, whereas right ear test scores were substantially
higher in the other three tests (PPS labeling, [Figure 3B ]; DPS pointing, [Figure 3C ]; and labeling, [Figure 3D ]). To facilitate comparison across samples and studies, we show in [Table 3 ] median scores and confidence intervals for each test across age and gender.
Figure 3 PPS and DPS test results by ear and sex. Number of correct responses for each ear
of each girl (female) and boy (male) responding by (A) Humming, (B, D) Labeling, or
(C) Pointing. Maximum score for each test was 30. Linear regression lines were fitted
to the PPS and DPS data that were symmetrically distributed about the mean.
Table 2
Sample (n = 228) Age, Mean Scores (% Correct), and Comparison between Tested Ear
Variable
Test Statistics, p Value
Age (years), Mean (SD)
9.3 (1.5)
Range
7–11.9
Male, n%
119 (52.2)
PPS
n = 211
Humming
Mean (SD)
Right ear
90.4 (10.1)
S = 1,013, p = 0.038[* ]
Left ear
91.3 (10.9)
Labeling
Right ear
74.6 (21.4)
t
(210) = 4.79, p < 0.0001[† ]
Left ear
70.4 (24.7)
DPS
n = 198
Pointing
Mean (SD)
Right ear
55.5 (23.3)
t
(197) = 4.52, p < 0.0001[† ]
Left ear
50.6 (25.2)
Labeling
Right ear
53.7 (23.4)
t
(197) = 5.81, p < 0.0001[† ]
Left ear
48.3 (24.7)
SD = standard deviation.
* Wilcoxon signed-rank test.
† Paired t -test.
Table 3
Median (5%, 95%) Scores for Each Test (out of 30) as a Function of Age and Sex (Ears
Averaged)
Age
PPS – Humming
DPS – Pointing
Girls
Boys
Girls
Boys
7
27 (21, 30)
29 (20, 30)
9 (4, 22)
14 (9, 29)
8
28 (17, 30)
29 (22, 30)
10 (5, 22)
15 (8, 25)
9
29 (22, 30)
28 (21, 30)
13 (7, 24)
23 (11, 29)
10
28 (23, 30)
29 (24, 30)
15 (8, 22)
22 (12, 27)
11
28 (24, 30)
28 (22, 30)
14 (5, 22)
21 (14, 28)
PPS – Labeling
DPS – Labeling
7
16 (7, 25)
25 (14, 29)
9 (5, 21)
13 (6, 26)
8
16 (7, 26)
23 (10, 29)
9 (5, 23)
16 (8, 25)
9
25 (11, 29)
26 (15, 29)
12 (6, 23)
23 (10, 28)
10
25 (18, 29)
27 (17, 30)
14 (8, 24)
19 (11, 28)
11
20 (9, 27)
28 (14, 30)
11 (5, 23)
23 (12, 28)
A major “ceiling” effect was observed in performance on the PPS humming test; 26.5%
(56/211) children scored 30/30 (i.e., 100%) correct in the right ear humming test
and 37.9% (80/211) in the left ear. For two-part modeling ([Table 4 ]), results for the first part showed that the left ear was associated with a significantly
higher probability of obtaining a 100% PPS humming test score than the right ear.
In the second part, for scores <100%, age had a marginally significant, positive linear
relationship with log humming test score (p = 0.05). No gender difference was found on this test.
Table 4
PPS Humming
Model 1: 100%
Model 2: <100%
Age
0.26
0.05
Sex
0.89
0.33
Ear
0.0004
0.57
Note: p values from repeated measures two-part model. Model 1 was a repeated measures analysis
using logistic regression to predict the probability of full score (i.e., all 30 correct;
100%). Model 2 was a repeated measures analysis using GLMM to predict test scores
less than 30 (<100%).
For all three remaining tests (PPS labeling, DPS pointing, and DPS labeling), older
children had higher scores than younger children, boys had significantly higher scores
than girls, and scores were higher in the right than in the left ear ([Table 5 ]). For PPS labeling, there was a weak but significant interaction between age and
gender, with younger girls performing relatively better than older girls. A significant,
positive linear relationship was found between age and test score for each test ([Figure 3 ]). Note that the PPS labeling test results also had a marked ceiling effect. However,
the GLMM analysis is robust for this variance heterogeneity and nonnormality and showed
good fit indices.
Table 5
Significant p Values from Repeated Measures GLMM Analysis
PPS Labeling
DPS Pointing
DPS Labeling
Age
0.005
<0.0001
<0.0001
Age * Sex
0.021
Sex
0.016
0.016
0.016
Ear
<0.0001
<0.0001
<0.0001
All four test scores were significantly, positively related ([Figure 4 ]; [Table 6 ]). The humming score was only weakly correlated with other tests (ρ = 0.17–0.34),
likely due to the strong ceiling effect. PPS labeling scores were moderately correlated
(ρ = 0.60–0.68) with DPS tests. The two DPS test scores were strongly associated (ρ
= 0.76–0.85). The test scores between the two ears were also strongly correlated,
with ρ ranging from 0.72 to 0.85.
Figure 4 Scatter plots between scores on each test using different response modes (Humming/pointing,
Labeling) and different ears (left, right).
Table 6
Spearman Rank Order Correlation (ρ) among Test Scores
PH_Right
PH_Left
PL_Right
PL_Left
DP_Right
DP_Left
DL_Right
PH_Left
0.72
PL_Right
0.23
0.32
PL_Left
0.26
0.34
0.84
DP_Right
0.20
0.22
0.60
0.61
DP_Left
0.24
0.30
0.65
0.68
0.81
DL_Right
0.17
0.25
0.60
0.62
0.80
0.83
DL_Left
0.18
0.27
0.66
0.67
0.76
0.85
0.85
Note: All p values were significant (p < 0.05); strong associations (>0.7) are in bold font. PH = PPS humming; PL = PPS
labeling.
DISCUSSION
Performance on these commonly used PPS and DPS tests varied in a number of ways. Older
children performed better than younger children on both tests. Children of all ages
performed better on the PPS than on the DPS. They also performed better when asked
to hum the tones they had heard than when asked either to point at concrete objects
representing the tones or to label the tones verbally. Boys performed better than
girls on all tests except the humming test. Stimulation of the right ear gave better
results than stimulation of the left ear in three of four tests. Finally, ceiling
effects were apparent in the PPS, particularly for older children. Despite these differences,
performance of individual children on the two tests was highly correlated.
Sampling and Normalization
Although this was not intended to be a normalization study, it raised some general
questions about recruitment of children for clinical trials of hearing tests and about
published normalization values for the PPS and DPS. Because of strict inclusion and
exclusion criteria, nearly half the children recruited did not start or complete the
test battery. Who is a “typical” child? It depends on the aim of the study. Here,
we were primarily interested in comparing performance across tests, stimuli, and response
modes, so selecting a relatively able group of children seemed appropriate. However,
these children could not be regarded as “typical.” For a study focusing on normalization,
it is important to recruit across the entire ability range, including population proportionate
numbers of children who may be disabled or have other participation difficulties.
In this well-powered study, we found some relatively subtle differences that may not
have been observed with a smaller or more heterogeneous sample. For example, we found
small but highly significant right ear advantages for all tasks except the humming
task, where a much smaller left ear advantage, obscured by the ceiling effect, was
seen. It appears that previous studies of “frequency pattern tests” (FPTs) have not
observed an ear advantage ([Weihing et al, 2015 ]). Differences between boys and girls were also seen in three of four tests and these
have, likewise, not been previously reported. The number of boys and girls excluded
before testing was about equal, so that was not the source of the performance differences
reported. We do not know of any other reason why boys performed better.
The large sample used here provided age-related estimates of performance on the PPS
and DPS that may have clinical interest. [Musiek (2002) ] and [Weihing et al (2015) ] have presented FPT “norms” of 40%, 65%, 72%, and 75% based on age (8, 9, 10, 11+
years old). FPT stimuli differed from the present study in frequency of the high pitch
stimulus (1122 versus 1430 Hz), duration (150 versus 500 msec), and interstimulus
interval (200 versus 300 msec). In each respect, the PPS tests we used should be easier
for the children to perform than the FPT tests. Nevertheless, their values are roughly
in line with the labeling data here, expressed as percentages (regression line), except
at the lower end (mean left and right, 7, 8, 9, 10, 11 years old; 54%, 77%, 73%, 78%,
84%). For the humming response, by contrast, our data are more like [Musiek’s (1994) ] adult data, “mean” of 88–92% with little age-related change due to the dominant
ceiling effect, also found in another recent, independent, and even larger clinical
service study ([Moore et al, 2017 ]). For the DPS, equivalent age “norms” for the data presented here were 37%, 45%,
48%, 61%, and 67%. A major reservation concerning the use of these or any other percentage-based
norms is that parametric statistics are clearly inappropriate for ceiling results.
The PPS humming data, for example, make little sense to report as means and standard
deviation ([Tables 2 ] and [3 ]). The other scores were less affected, but the PPS labeling scores of the older
children were also hitting ceiling. A detailed critique of percentage scores is provided
by [Tomlin et al (2014) ]. A further complication is that, according to [Tomlin et al (2014) ], the FPT normalization data are “cutoff scores” rather than a measure of central
tendency as used here. Agreed standards for reporting of normalization are much needed.
Maturation
Almost all studies of the development of hearing have shown superior performance in
older than in younger children and almost all those studies have suggested an end
point of maturation between 6 and 12 years ([Werner, 2007 ]; [Moore et al, 2011 ]; [Sanes and Woolley, 2011 ]). Analysis of the data shown here suggested that performance on the PPS humming
task changed marginally from 7 to 11 years of age. For the other tasks, performance
varied substantially between individuals, but there was a relatively steady, linear,
and significant increase across this age range, suggesting that further development
into adolescence was likely, as shown in a few studies ([Huyck and Wright, 2011 ]; [Sanes and Woolley, 2011 ]). Generally, our ability to observe maturation depends critically on the task. It
is a very demanding requirement for tests such as DPS or FPT with fixed response levels
(i.e., nonadaptive) to avoid floor or ceiling effects across a wide range of ages
and abilities. This point is discussed further in the following textfor the present
study, but a previous study ([Moore et al, 2010 ]) examined the maturation of auditory temporal and spectral resolution in a very
large, cross-sectional sample of 6- to 12-year-old children using two methods. Using
one method, they found typical, substantial, and asymptotic maturation when performance
was measured on each one of five tests. However, when a different method was used
that compared performance between two versions of each task (e.g., the duration of
a gap between a tone and a following masking noise), keeping the cognitive demands
essentially identical, “no” maturation was seen. Further details of this experiment
are provided in the next section and in [Moore (2012) ]. This result suggested that measuring sensory maturation using a single behavioral
test can produce potentially misleading results. We may assume that the test measures
maturation of a sensory attribute (e.g., auditory temporal processing). But this study
showed no change with age when nonauditory performance factors were eliminated.
Task Effects
We found that humming the tone pattern generally produced better performance in the
same child than either articulating the attributes of the tones (labeling) or pointing
to physical representations of their duration. This suggests that different mechanisms
are involved in these responses and that, contrary to current APD recommendations
([Musiek, 2002 ]), results from humming should not clinically be combined with or be a substitute
for results obtained from the usual labeling task. However, these various response
tasks may be useful in further research to identify brain regions involved in normal
and impaired auditory processing, for example in future studies using magnetic resonance
imaging to help determine the role of various auditory and multimodal cortical areas
in processing pattern sequence signals and performing the tests.
It is well understood in psychoacoustics that presenting a multiple choice task with
minimal need to understand the properties of the stimulus gives more reliable and
better performance. For example, three- or four-interval forced choice frequency discrimination
tasks, asking the listener to pick the odd one out, are preferable to tasks requiring
choice of the “higher pitched” stimulus ([Amitay et al, 2006 ]). To measure task performance, it is also preferable to use adaptive procedures
that track the listeners’ threshold rather than predetermined step sizes and “percent
correct” measures. These procedures give a more unbiased estimate of task performance
by avoiding ceiling effects and minimizing the cognitive demands of the task. They
are also more efficient because they provide fewer “easy” trials that provide minimal
evidence about ability. With current availability of good quality sound delivery via
laptop or tablet computers, there is an urgent need to develop future tests for auditory
processing using these basic design features. [Grube et al (2012) ] provide an example of how pitch pattern and other auditory sequence tasks may be
tested this way. Although humming may be a desirable response output in terms of lack
of postperceptual effort, it rests on the ability of the child to accurately reproduce
the stimulus and the ability of the tester to interpret the hum.
Pitch and duration pattern tests generally use a labeling response as the default
mode of responding ([Musiek et al, 2011 ]; [Weihing et al, 2015 ]). Although pattern tests may have a place in the assessment of higher level function
([ASHA, 2005 ]), tasks that rely on labeling a tonal stimulus should be avoided in testing hearing,
at least for children and other special populations such as the elderly or those with
known cognitive difficulties. Labeling adds a further level of difficulty to the response
that is distinct from the skill to be measured, auditory perception. It is increasingly
recognized that cognitive function is inextricably linked with all auditory tasks,
even nonspeech tests using the psychoacoustic procedures described previously. For
some tests, notably those involving speech perception, decoding and understanding
the speech signal is an unavoidable aspect of the task. But for both nonspeech and
speech tests, an assessment of auditory processing should aim to minimize attention,
memory, language, and learning effects. This can be achieved to a considerable extent
by using “derived” or “subtraction” techniques, as described previously ([Moore et al, 2010 ]; [Moore, 2012 ]) and in other recent papers ([Dillon et al, 2014 ]; [Cameron et al, 2016 ]), where the cognitive elements are to a large extent cancelled out by subtracting
two similar versions of the same test that vary only in the critical auditory element
of interest. This design should become a standard element of clinical and research
tests.
Studies of patients with lesions of the central auditory nervous system have shown
that performance on PPS-like tests is affected in a smaller proportion of patients
than is performance on DPS-like tests, leading to a suggestion that these tests involve
different functional processes ([Musiek et al, 1990 ]). However, we found that performance on the PPS and DPS tests was highly correlated
among the large sample of high functioning children examined in this study. The limiting
factor for observing this relationship appeared to be a ceiling effect of the PPS
test rather than a functional difference between children. It is possible that the
previous results reflected the greater difficulty of the DPS together with an overall
poorer performance of the patients, resulting in more of them scoring below the “cutoff”
(2 standard deviation < normal mean).
Study Limitations
The test order was fixed in this study ([Table 1 ]). A preferable design would have been to pseudorandomize the test order between
the various conditions in a Latin Square design to ensure each test occurred in each
order of presentation. In general, no systematic differences were found between tasks
or ears as a function of test order. Right ear performance was generally better than
that of left ear but, for the humming task, left ear performance was superior to that
of right ear among those scoring 100%. It is possible that this left ear superiority
was a learning effect, as right and left ear humming were, respectively, the first
and second pattern sequence tests administered. In the third session, performance
did not differ significantly between the pointing and labeling tasks ([Table 2 ]).
We used the “child” PPS that, as elaborated previously, is easier than the more commonly
used FPT ([Tomlin et al, 2014 ]). It is therefore likely that the difference in score reported here between the
humming and labeling versions of the PPS would be less marked in the FPT, assuming
that humming scores would not reach ceiling as readily with the more difficult task.
Finally, the reliability of producing and judging a hummed response is largely uncontrolled.
This issue could be addressed to some extent by using two or more “observers” (test
staff), but the general point is that participant-selected, quantitative measures
(e.g., two alternative forced choice; [Grube et al, 2012 ]) are preferable to subjective opinion of either the participant or the examiner.
Clinical Implications
Future use and interpretation of pitch and duration pattern tests should not combine
data from humming tones with other forms of response. Because of the ceiling effects
in PPS, even in 7-year-olds, it may not be advisable to use the humming response at
all. One advisory on this conclusion is, however, that the sample tested here was
clearly not representative of the general population. Thus, although some use may
be made of these data for normalization purposes, it seems likely that many children
who did not pass our stringent inclusion criteria could have brought the mean scores
down and simultaneously reduced the ceiling effect, as found in studies of children
with impaired reading performing the PPS ([Walker et al, 2006 ]) and those using more difficult tone pattern tasks ([Tomlin et al, 2014 ]). The age of the child should also be borne in mind when interpreting the results
and, for the tasks used in this study, gender and stimulated ear were also important,
in contrast to the findings of [Willeford (1985) ] and [Musiek (1994) ].
A final question is whether these and other tests of simple auditory function are
useful for diagnosing and managing APD. We live in an acoustically busy and complex
world, with sounds coming at us from all directions. Speech is the principal sound
we listen to, and that speech is commonly masked by other speakers. Although sound
patterns are clearly of importance in perceiving speech, for example, by segregating
speech into auditory objects ([Bregman, 1990 ]), it seems a big difference between the complexity and rapid modulations of everyday
speech and the very slow modulations and spectral purity of the PPS, DPS, and other
commonly used tone pattern tests ([Emanuel et al, 2011 ]). Further research might focus on the relation between these tests and more functionally
meaningful indices of hearing. A recent study that performed such a comparison showed
modest but significant correlations between the FPT ([Musiek, 1994 ]) and functional benchmarks of listening ability and reading fluency ([Tomlin et al, 2015 ]). These correlations were similar to those achieved by the subtests of the Listening
in Spatialized Noise-Sentences Test, a speech-in-noise test that has many features
of real-world sound listening ([Cameron and Dillon, 2007 ]). All auditory processing (AP) test scores were, however, poorer predictors of the
benchmark measures than tests of nonverbal IQ and auditory working memory ([Tomlin et al, 2015 ]). It may, therefore, be asked whether the weaker correlations obtained with the
benchmarks by the AP tests ([Tomlin et al, 2015 ]) were due to the auditory or to the cognitive demands of the AP tests.
CONCLUSION
Asking children to hum the tone pattern in the PPS produced generally better performance
than articulating the attributes of the tones (labeling). In the DPS, pointing to
objects did not produce any benefit over labeling. Performance on both tests improved
with age. Group performance on the PPS was better than that on the DPS, but individual
performance on the two tests was highly correlated.
Abbreviations
AP:
auditory processing
APD:
auditory processing disorder
ASHA:
American Speech-Language-Hearing Association
DL:
DPS labeling
DP:
DPS pointing
DPS:
duration pattern sequence
FPT:
frequency pattern test
GLMM:
generalized linear mixed models
PPS:
pitch pattern sequence