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Contralateral induction by frequency spectrum in hallucinating schizophrenics


Abstract and Figures

Seventeen schizophrenic patients who had all experienced auditory hallucinations were compared with 14 subjects of a reference group on a test of contralateral induction. Contralateral induction means that a sound is illusively heard as coming from a location where it belongs according to its spectral content. The phenomenon is connected with a simultaneous relative elimination of masking. The schizophrenic subjects deviated from the reference group in several aspects. Some of them did not hear the sound being induced to the contralateral side, which it was for all reference subjects. Another subgroup of the schizophrenics noticed the induction unusually early with a prolonged experience of it, and finally some of them experienced the induction now and then. The aberrations were interpreted as rigidity of adaptation on the one hand and as effects of an enhanced sensitivity on the other. Discontinuity, meaning that the fluency in mental processing is broken, was interpreted to cause the ratings of the third group of schizophrenics in this sample, who heard the contralateral induction now and then. These phenomena are clearly reminiscent of descriptions in research reports, and witnessed by clinical experience of the schizophrenic disturbance. The results represent another example of discontinuous neurophysiological functions between neural systems and between individuals suffering from schizophrenia.
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Psychiatry Research 87 1999 65]75
Contralateral induction by frequency spectrum in
hallucinating schizophrenics
Olle OlssonU, Soren Nielzen
Di¨ision of Psychiatry, Department of Clinical Neuroscience, Uni¨ersity Hospital, SE-221 85 Lund, Sweden
Received 29 May 1998; received in revised form 10 November 1998; accepted 29 December 1998
Seventeen schizophrenic patients who had all experienced auditory hallucinations were compared with 14 subjects
of a reference group on a test of contralateral induction. Contralateral induction means that a sound is illusively
heard as coming from a location where it belongs according to its spectral content. The phenomenon is connected
with a simultaneous relative elimination of masking. The schizophrenic subjects deviated from the reference group in
several aspects. Some of them did not hear the sound being induced to the contralateral side, which it was for all
reference subjects. Another subgroup of the schizophrenics noticed the induction unusually early with a prolonged
experience of it, and finally some of them experienced the induction now and then. The aberrations were interpreted
as rigidity of adaptation on the one hand and as effects of an enhanced sensitivity on the other. Discontinuity,
meaning that the fluency in mental processing is broken, was interpreted to cause the ratings of the third group of
schizophrenics in this sample, who heard the contralateral induction now and then. These phenomena are clearly
reminiscent of descriptions in research reports, and witnessed by clinical experience of the schizophrenic disturbance.
The results represent another example of discontinuous neurophysiological functions between neural systems and
between individuals suffering from schizophrenia. Q1999 Elsevier Science Ireland Ltd. All rights reserved.
Keywords: Sound localization; Laterality; Masking; Auditory hallucinations
UCorresponding author. Tel.: q46-46-1738-88; fax: q46-46-1738-84.
E-mail address: O. Olsson
0165-1781r99r$ - see front matter Q1999 Elsevier Science Ireland Ltd. All rights reserved.
PII: S 0 1 6 5 - 1 7 8 1 9 9 0 0 0 4 0 - 2
O. Olsson, S. Nielzen rPsychiatry Research 87 1999 65]75
1. Introduction
1.1. Psychoacoustic background
The ability to localize sound rests on the fact
that interaural time differences ITDs from the
right to the left ear offer a phase displacement
which is liable to neurophysiological analysis. One
of the ears will as well most of the time find itself
in a shadow in relation to the other one. This
causes an interaural intensity difference IID
between the ears. These two circumstances con-
stitute the basis for a theory of localization called
‘Duplex Theory’. However, many other physical
properties determining localization of the sound
wave are watched by the analysing hearing sys-
tem. As examples may be mentioned different
high frequency filtering by the two pinnae outer
ear cartilage , which helps vertical orientation
Lackner, 1974; Guterman and Klein, 1992 , bin-
aural masking, dichotic pitch, and binaural beats
Yost and Dye, 1991 .
The acoustic phenomenon of contralateral in-
duction may occur under specific circumstances,
and it was partly described for different cases by
Egan 1958 . It consists of the fact that brain
processes compare and segregate input to the two
ears Warren and Bashford, 1976 . This means,
for example, that a tone, noise, or complex sound
presented to one ear may-be localized to the
middle or opposite side, if on the opposite side
there is a simultaneous stimulation with spectral
components corresponding to the former side.
The phenomenon is related to masking, release
from masking, fusion, fission, and possibly other
mechanisms, but constitutes a separate feature as
well. It may be most importantly seen as a com-
pound process based on spatial estimates of con-
flicting cues in the spectral domain for the two
ears. Spatial origin is important as a cue for
auditory scene analysis, but can be overwhelmed
by other cues. Therefore, contralateral induction
may be studied best in strict laboratory situations.
In everyday life it is a useful means to avoid
confusion of spatial origin of sounds Bregman,
1990 .
Neurophysiologically, the nervous system con-
structs percepts by collected and purified infor-
mation from the two ears. Bushy cells in the
anterior ventral cochlear nucleus put their elec-
trical discharge representing specific frequencies
into the same phase, and thereby a safe bilateral
system of transmitting ITD differences is consti-
tuted. IID differences are treated by a circuitry
involving basically the anterior ventral cochlear
nucleus, the lateral superior oliva, and the medial
nucleus of the trapezoid body Brugge, 1988 . The
coding of lateralization takes place by unilateral
and contralateral inhibition, facilitation, and
adaptation under the influence of superimposed
efferent activity. In this process various forms of
coding are used by the nervous system, effectu-
ated by the sensitivity of cells for stimulus-rate
variations, by synchronization coincidences, and
by cells especially developed to react to amplitude
modulation, phase modulation, and frequency
ŽLindemann, 1986; Hafter et al., 1988; Schreiner
and Langner, 1988; Yin and Chan, 1988 .
A possibility to trace the origin of lateralization
in humans is offered by the study of brainstem
auditory evoked potentials in combination with
other methods. Levin et al. 1993 have traced
deficient acuity of localization in patients with
multiple sclerosis due to different lesions in the
superior olivar complex-trapezoid body system,
the ventral acoustic stria, and the nuclei of the
lateral lemniscus. Spatial tuning within superior
levels is based on this primary information and is
elaborated within colliculus inferior and cortex
Ehret, 1988; Middlebrooks, 1988 . The circuitry
serving processes like masking are but incom-
pletely elucidated. The same applies to the
phenomenon of contralateral induction. However,
contralateral induction is considered to be a pri-
mary psychoacoustical process, dominantly han-
dled at evolutionarily low levels in the brain stem
Hafter et al., 1988 .
1.2. The schizophrenic context
Few studies on schizophrenics and sound local-
ization have been performed. In a study by
O. Olsson, S. Nielzen rPsychiatry Research 87 1999 65]75
Gruzelier and Hammond 1979 , dichotic stimula-
tion and various verbal and non-verbal tests were
used to assess hemispheric differences. An indica-
tion of deficient pathways to the left hemisphere
was obtained and the hippocampus was assumed
to be implicated due to results of impaired short-
term memory retrieval and efferent control of
sensory input.
In a study by Bruder and Yozawitz 1979 no
evidence of abnormal auditory lateralization
asymmetries was noticed. Guterman and Klein
1992 described deficiencies of vertical localiza-
tion ability among schizophrenics. There was a
different function between pinnae-dependent and
ITD-dependent information, compared to normal
subjects. Lackner 1974 took the body position
Fig. 1. Display of the experimental situation. Top left distractor sound, top right target sound.
O. Olsson, S. Nielzen rPsychiatry Research 87 1999 65]75
into acount. Schizophrenics seemed to have a
deficient ability to correctly localize a sound when
asked to relate it to the proprioceptive experi-
These studies suggest that there are subtle
differences of various complex functions in
schizophrenics with regard to localization tasks,
although no indications of basic hearing function
deficits, such as threshold differences, etc., are
found. It might therefore be reasonable to as-
sume that the psychophysical task planned for the
present study will cause a difference betweeen
healthy subjects and schizophrenics, due to its
challenge of an integrated grouping function.
The schizophrenic auditory hallucination dif-
fers from organic, epileptic or toxic hallucinations
Walter et al., 1990; Steinberg et al., 1998 . In the
beginning of the illness there are primary delu-
sions and misperceptions reminiscent of elemen-
tary psychoacoustical disturbances. These may
consist of hearing minute sounds as disturbingly
loud, distorted or impossible to locate. Not until
later stages of the illness are the hallucinations
interpreted in constant patterns, and filled with
content Conrad, 1958 .
The rationale for this study is the assumption
that primary schizophrenic disturbances might ex-
press themselves in processes demanding a group-
ing activity of the percept by the brain. This may
apply to individuals with auditory hallucinations
in their past history, where auditory function is
involved in the development of psychopathologi-
cal symptoms. An experiment offering a conflict
between localization and recognition of a sound,
depending on its spectral content, will be used.
2. Aims of the study
The aim of this study is to investigate the
functioning of a psychoacoustic separation
process, where the perception of localization is
‘released’ by the influence of a second sound.
Cues of frequency content ‘extract’ the first sound
from its original location. This is called contralat-
eral induction. It is assumed that schizophrenics
Fig. 2. Frequency distribution of individuals who have heard
the movement of the target sound right towards the distrac-
Ž. Ž .
tor left . Unfilled bars sreference group ns14 and filled
bars sschizophrenics ns17 .
with auditory hallucinations in their past history
will show impairments of this integrative function.
3. Methods
3.1. Stimuli
Two stimuli were created, one to be used as
target and the other as distractor. The first was
constructed in MATLAB 5.1 by collecting 12
sinewaves 100, 200, 300, 400, 500, 600, 700, 800,
900, 1000, 1100, and 1200 Hz . The second was
combined of five sinewaves 100, 200, 400, 800,
and 1200 Hz . All sinewaves had the same ampli-
tude and starting phase angle. The envelope fol-
lows the formula:
The rise time becomes 0.16 s, the decay time
0.27 s, as the total duration was set to 0.5 s. These
O. Olsson, S. Nielzen rPsychiatry Research 87 1999 65]75
values were chosen in order to avoid distortion in
the experiment due to too short rise times.
3.2. Equipment
The stimulus was constructed by the use of the
software MATLAB 5.1 , Signal Processing Tool-
box and a Macinthosh Quadra 650 with a built-in
Power PC 601 card. The stimuli were sampled
into a Kurzweil K2000 and MIDI-controlled by
the software Digital Performer on a Macintosh
LCIII. The stimuli were presented via a Teac
W-900RX cassette tape recorder and a Yamaha
CA610 amplifier with two Heybrook HB1 loud-
3.3. Procedure
The subjects were seated in a laboratory at a
distance of 1.5 m from each loudspeaker. The
azimuth angle between the loudspeakers was 908
Fig. 1 .
They were presented with a written instruction
describing target and distractor, and the mode of
presentation. Thereafter, they had the opportu-
nity to listen to the separate sounds and were
asked to discuss the experiment with the test
leader in order to ensure that they had under-
stood the meaning of the experiment.
The test was divided into 16 presentations. In
each of them the distractor the 12 partial sound
was delivered through the left loudspeaker, first
with 0 dB. From the second presentation an in-
crease by 4.5 dB in amplitude was made from the
base value of 39 dB arriving at 76 dB at the
eighth presentation. The amplitude of the ninth
presentation was equally 76 dB and then the
amplitude decreased by 4.5 dB until the 16th
presentation. The target the five partial sound
was presented simultaneously through the right
loudspeaker at a constant amplitude of 68 dB.
The subjects were asked to mark a 0 when they
could hear the target clearly coming from the
right loudspeaker and an X if they heard it move
towards the left one. When the SPL of the dis-
Table 1
Some identifying and background variables of the subjects with schizophrenic symptoms
Ind. Age Sex Medication No. of Duration of DSM-IV No. of months
Ž. Ž.
no. mgrweek admissions illness years diagnosis as inpatient
1 44 M Zuclopenthixole 4 11 295.30 8
decanoate, 100
2 37 F Zuclopenthixole 5 8 295.10 3
decanoate. 50
3 35 M Clozapine, 4200 7 7 295.30 15
4 34 F Clozapine, 350 8 4 295.30 14
5 22 F Perphenazine, 84 1 3 295.10 1
6 27 F Clomipramine, 525 4 8 295.40 15
746M ]1 10 295.90 1
8 36 F Roxiam, 4800 2 9 295.30 1.5
9 38 M Roxiam, 5250 10 12 295.30 17
10 46 M Haloperidol 5 4 295.30 1
depot, 50
11 30 F Perphenazine, 280 6 4 295.30 6
12 31 F Perphenazine, 280 4 5 295.30 4
13 28 F Clozapine, 2100 6 12 295.30 8
14 32 M Clozapine, 1750 6 7 295.30 13
15 49 F ]0 1 295.30 0
16 33 M Clozapine, 1750 2 12 295.30 7
17 34 M Perphenazine, 84 1 2 295.30 3
aMsmale and Fsfemale.
O. Olsson, S. Nielzen rPsychiatry Research 87 1999 65]75
Table 2
Number of Xs perception of contralateral induction for 16 presentations to the test groups
12345 6 7 8 9 10111213141516
RG0002 5 710141211 7 21000
S 134813151314141310109551
x0.01 1.09 1.98 2.42 3.70 3.75 0.09 1.09 0.56 0.85 0.17 4.68 5.42 2.98 2.98 0.01
P0.92 0.30 0.16 0.12 0.05 0.05 0.92 0.30 0.81 0.77 0.90 0.03 0.02 0.08 0.08 0.92
RG, reference group ns14 .
S, schizophrenics ns17 .
O. Olsson, S. Nielzen rPsychiatry Research 87 1999 65]75
tractor becomes equal to, or louder than the
target, the sounds are generally perceived as one
sound coming from the middle or from near the
3.4. Subjects
Seventeen former in-patients at the University
Hospital in Lund were asked to take part in the
study. The inclusion criteria were: a diagnosis of
schizophrenia with typical schizophrenic auditory
hallucinations in the past history, but no present
hallucinations during testing. The diagnosis should
have been established on clinical examination by
a senior medical doctor. It had to comply with the
criteria of schizophrenic psychosis as defined in
DSM-IV American Psychiatric Association, 1994,
pp. 285]286 . Exclusion criteria were organic
brain diseases, alcohol or drug abuse, or the
presence of additional psychiatric diagnoses. A
formal consent was ascertained in accordance with
the requirements of the ethical committee LU
171-94 . Table 1 presents the patient sample.
The reference subjects were recruited among
medical students and staff. There were eight fe-
males and six males, the mean age being 29 with
Eight patients with panic disorder, according to
the criteria of DSM-IV, were additionally in-
cluded in the study. Their ages ranged from 30 to
55 years, and there were five females and three
4. Results
The frequency distribution of all individuals
divided into a schizophrenic black bars and a
reference group white bars is presented in Fig. 2
and Table 2.
Obviously, schizophrenics differ from the sub-
jects of the reference group in the beginning
presentation 1]6 of the experiment and in the
end presentation 12]16 . There is a statistically
significant difference between the group of refer-
ence subjects and that of schizophrenics
ŽKolmogorov]Smirnov tested for the entire dis-
tribution, Zs2, Ps0.03 . In other words, some
of the schizophrenic patients must experience the
movement of the target earlier than the reference
subjects do, and some of them hear the pheno-
menon longer than the reference subjects. How-
ever, where contralateral induction becomes com-
plete among the reference subjects around pre-
sentation 8 , it is also at hand among most of the
schizophrenics. The irregularity of the frequency
distribution of the schizophrenics calls for a closer
analysis regarding the existence of different rat-
ing strategies in subgroups see Table 3 . It turns
out that one subgroup ns7 seems to experi-
ence the contralateral induction in a quite normal
way. For two individuals no contralateral induc-
tion seems to take place, and they experience the
target sound as coming from the right loud-
speaker all the time. A few schizophrenics ns4
start earlier and keep their impression of a fused
sound to late stages. Finally, four individuals hear
the target sound coming from the right and the
left loudspeaker intermittently.
In order to test the validity of the rating proce-
dure among the schizophrenics, a comparison was
made with data achieved in another experiment
performed by all subjects on the same occasion.
This experiment was one of streaming which is a
test on grouping of high and low sounds depend-
ing on amplitude Nielzen and Olsson, 1997 . It
was similarly organized in 16 presentations. It
turned out that the schizophrenic probands could
be sorted out in the same different rating sub-
groups as in the present study. A Mann]Whitney
test between streaming and contralateral induc-
tion regarding the different response categories
Žno recognition of target phenomenon, starting to
hear it earlier, and hearing it intermittently
yielded Z, corrected for ties sy2.154; Ps0.03.
The rating responses are therefore not random,
but varying, depending on different experiments.
A test was made to look for a possible influ-
ence of anxiety on test results. The compari-
son was made on a sample of anxiety patients
Ž. Ž .
ns8 , the reference group ns14 , and the
schizophrenic group ns17 . A Kruskal]Wallis
variance test showed a difference at a highly
significant level Hs12; d.f.s2; Ps0.0002 . A
pair-wise comparison by Mann]Whitney tests
between the three groups gives the following re-
O. Olsson, S. Nielzen rPsychiatry Research 87 1999 65]75
Table 3
The distribution of the individual schizophrenic probands regarding different strategies of perception
Normal No induction Earlyrlate Induction now and then
Ind. no. 1, 2, 9, 10, 14, 3, 11 4,6,7,8 5, 12, 13, 16
15, 17
sult: schizophrenicsranxiety patients; Z, cor-
rected for ties sy3; Ps0.002, anxietyrrefer-
ences; Z, corrected for ties sy6; Ps0.0001,
schizophrenicsrreferences; Z, corrected for ties
sy3; Ps0.0005. The mean number of presen-
tations, when the movement was identified was
about the fifth for the reference subjects, about
the sixth for the schizophrenics, and the eighth
for the anxiety group.
This means that schizophrenics and anxiety
patients tend to hear the phenomenon late and
much too late, respectively cf. Section 5 .
Comparisons were further performed on clini-
cal measures Table 1 , but no correlations or
differences were statistically significant. There
were also no age differences. Sex, however, dif-
ferentiated the ratings. Schizophrenic women
differed from women in the group of reference
subjects in a statistically significant way
Mann]Whitney, Ps0.0001 . Schizophrenic men
differed from men in the group of reference
subjects, in the same direction as schizophrenic
women, but in a non-significant way Mann]
Whitney, Ps0.25 .
Although several schizophrenic subjects seem
to perceive the contralateral induction in a nor-
mal way, there is a considerable number of them
who do not. This circumstance necessitates fur-
ther considerations and a discussion Table 3 .
5. Discussion
Contralateral induction operates on the condi-
tion that a target sound may he relocated in the
hearing system by an inducing sound. For this to
happen, the inducer must contain the same fre-
quency components as the target and it must
supply the nervous system with sufficient energy
high amplitude . The induction will not occur if
the target and inducer do not have exactly the
same duration, phase, and envelope Bregman,
1990 . On the psychoacoustic level one percept is
extracted from its original position and relocated
to a surrounding where there is pattern evidence
of similarity. This process is intimately connected
with masking.
This study was undertaken on the assumption
that schizophrenia is connected with perceptual
disturbances including primary psychoacustical
malfunctioning. Such a disturbance may be of
importance for further investigations regarding
relations to localization processes and auditory
Before further discussion of the present results,
a few aspects may be discussed regarding method-
Some researchers claim that schizophrenics are
not able to handle a test situation. The impact of
the illness may be considered to hamper the
results due to lack of attention, preoccupation of
symptoms, motoric incapability, etc. On the other
hand, schizophrenics sometimes perform better
than normal subjects do, as Hemsley 1993
pointed out in connection with cognitive experi-
A comparison was made between the present
psychoacoustic test and another one cf. Section
4 performed at the same time by the same
schizophrenic subjects. It showed that the rating
responses varied from experiment-to-experiment
at a statistically significant level. This supports the
validity of the rating performance of the
schizophrenic probands. The reliability was fur-
ther checked by comparisons made in this and
earlier psychoacoustic experiments. No statisti-
O. Olsson, S. Nielzen rPsychiatry Research 87 1999 65]75
cally significant differences from reference sub-
jects were found on this general level, which
supports the existence of a sufficient reliability.
However, there still remains a question whether
the schizophrenics rate according to what is really
heard or in response to their subjective impres-
sion, influenced by interfering mental processing.
This question, inherent in most studies of percep-
tion, could only be answered by means of comple-
mentary correlative studies with various objective
It is likewise necessary to consider the fact that
ratings may be influenced not only by the
schizophrenic illness but by other background
factors. Generally, the impact of schizophrenia is
much greater than any other psychiatric illness as
seen from many investigations of this kind. The
influence of other background factors such as
age, sex, education, etc., is usually still less than
the influence of schizophrenia Nielzen, 1982;
Steinberg, 1986 . In order to test the possible
influence of a common confounding symptom,
namely anxiety, a sample of eight panic disorder
patients was included for the purpose of compar-
ison. It turned out that schizophrenics, anxiety
patients, and subjects of the reference groups
differed significantly. The subjects of the anxiety
group tended to rate a hearing of the contralat-
eral effect much later than the subjects of the
other two groups. Furthermore, a computation of
correlation with other psychoacoustical tests per-
formed at the same occasion showed no signifi-
cant correlations between anxiety and schizo-
phrenic subjects.
No statistically significant differences were
observed for any of the available clinical mea-
sures. An explanation may be that the inclusion
criteria limited the sample to a narrow group of
mainly paranoid schizophrenics, even perhaps
mostly phonemic paraphrenics. The lack of sig-
nificant influences from symptoms, medication,
duration of illness, etc., could mean that the
altered perception depends on more fundamental
factors of the illness. Age also had no significant
influence on the ratings, but there was an interac-
tion by sex. The schizophrenic women contribute
more to the group differences than schizophrenic
men do. Evidently, there are sex-related factors
that enhance the contralateral induction. A gen-
eral sensitivity factor in women could be one, but
the question requires further studies to be an-
The major finding of the study is that these
schizophrenics respond differently compared to
the subjects in the reference group. In order to
try to understand what the difference means, a
closer look at details of the rating responses has
to be taken.
Four subgroups of rating strategies among the
schizophrenics were identified. One of these sub-
groups showed a pattern coinciding with the re-
sponses in the reference group. The meaning of
this finding is that contralateral induction func-
tions in a normal way. The main hypothesis of the
study has to be rejected regarding these patients.
The majority of the patients in this study show
other patterns of rating, indicating that in certain
cases of schizophrenia there might still be some
disturbing influence upon mechanisms determin-
ing contralateral induction.
Two schizophrenics never heard any move-
ment. The suspicion that they were subjected to
some bias could be strong. However, one must
realize that not hearing the induction means that
the subject manages to hear the target sound in
the right loudspeaker all the time. This does not
occur for any non-schizophrenic person, or most
other schizophrenics. It implies such a strong
release from masking that induction is inhibited.
A psychoacoustic way of explaining what may
have happened is that for these schizophrenics,
recognition of the sound character, by suppress-
ing masking, has a priority over localization.
The third group is characterized by hearing the
movement of the target earlier, and holding onto
this percept for a long time. In opposition to the
former group, the schizophrenics in this group are
more ready to fuse the target and the inducer
than the reference group is. For these patients
masking has a dominant role.
In the last group there are four subjects who
mark an experience of the moving target in an
inconsistent way, thus noting the phenomenon
now and then. In one case there is even a motion
towards the distractor in the first presentation,
when no stimulation is given in the left speaker.
O. Olsson, S. Nielzen rPsychiatry Research 87 1999 65]75
One would be inclined to assign these aberrations
to the influences of random factors, but it is
important to remember that the probands had
been acquainted with the experiment by listening
to it just before testing. Similar patterns of rating
have been noted in perceptual experiments by
other researchers on schizophrenic psychophysi-
ology, and they have been interpreted as signs of
regression, which coincides with the clinical symp-
tom discontinuity Smith et al., 1972 .
A few unquestionable basic phenomena are
connected with the schizophrenic disease. One is
dishabituation, a lack of adaptation to new sti-
muli. Not hearing contralateral induction may be
interpreted as an effect of this phenomenon.
Those who start to hear it early are obviously
sensitive, another undisputed attribute connected
with the disease. Thirdly, perceptual discontinuity
is an uncontroverted feature of the disease. Those
who heard the induction now and then may show
precisely this disturbance.
Important parts of systems serving the mecha-
nism of localization operate in the brainstem.
They are structurally separated from systems in-
volved in the analysis of frequency, envelope, and
other features. The differences found here con-
trast to the current neurophysiological models of
explanations of schizophrenia. These are focused
on prefrontal cortex, the limbic system, and the
left temporal cortex. In view of the sparse litera-
ture on schizophrenia and psychoacoustics, forth-
coming research efforts in this field will in time
give valuable information about more neural net-
works related to schizophrenic symptoms.
To conclude, the results show that aberrant
perception of contralateral induction occurs in
this schizophrenic group in eight of 17 probands.
The schizophrenic probands have shown one type
of disturbance response strategy in the present
experiment, but a different one in another psy-
choacoustic test. There seems to be an intraindi-
vidual variation in schizophrenic influences of
different psychoacoustic mechanisms. Overall, the
study has shown aberrations reminiscent of some
characteristic schizophrenic perceptual aberra-
tions, dishabituation, sensitivity, and discon-
American Psychiatric Association, 1994. Diagnostic and Statis-
tical Manual of Mental Disorders. 4th ed., Washington,
Bregman, A.S., 1990. Aditory Scene Analysis. The Perceptual
Organization of Sound. MIT Press, Cambridge, Mas-
Bruder, G.E., Yozawitz, A., 1979. Hemisphere asymmetries of
function in psychopathology. In: Gruzelier, J. Ed. , Central
Auditory Processing and Lateralization in Psychiatric
Patients. Elsevier Science Publishers, Amsterdam, pp.
Brugge, J.F., 1988. Stimulus coding in the developing auditory
system. In: Edelman, G.M., Gall, E.W., Cowan, W.M. Eds. ,
Auditory Function. Neurobiological Bases of Hearing. A
Neurosciences Institute Publ., Wiley Interscience, New
Conrad, K., 1958. Die beginnende Schizophrenie. Versuch
einer Gestaltanalyse des Wahns. Georg Thieme Verlag,
Egan, J.P., 1958. The effect of noise in one ear upon the
loudness of speech in the other. Journal of the Acoustical
Society of America 20, 58]62.
Ehret, G., 1988. Frequency resolution spectral filtering and
integration on the neuronal level. In: Edelman, G.M., Gall,
E.W., Cowan, W.M. Eds. , Auditory Function. Neurobio-
logical Bases of Hearing. A Neurosciences Institute Publ.,
Wiley Interscience, New York.
Guterman, Y., Klein, E., 1992. The role of head movement
and pinnae in auditory localization in schizophrenia and
psychosis. Schizophrenia Research 6, 67]73.
Gruzelier, J., Hammond, N., 1979. Hemisphere asymmetries
of function in psychopathology. In: Gruzelier, J. Ed. ,
Lateralised Auditory Processing in Medicated and Unmed-
icated Schizophrenic Patients. Elsevier Science Publishers,
Amsterdam, pp. 603]636.
Hafter, E.R., Buel, T.N., Richards, V.N., 1988. Onset-coding
in lateralization: its form, site, and function. In: Edelman,
G.M., Gall, E.W., Cowan, W.M. Eds. , Auditory Function.
Neurobiological Bases of Hearing. A Neurosciences Insti-
tute Publ., Wiley Interscience, New York.
Hemsley, D.H., 1993. A simple or simplistic? cognitive model
for schizophrenia. Behaviour Research and Therapy 31 7 ,
Lackner, J.R., 1974. Changes in auditory localization during
body tilt. Acta Otolaryngologica 77, 19 ]28.
Lindemann, W., 1986. Extension of a binaural cross-correla-
tion model by contralateral inhibition. I. Simulation of
lateralization of stationary signals. Journal of the Acousti-
cal Society of America 80 6 , 1608 ]1622.
Levin, R.A. et al., 1993. Effects of multiple sclerosis brainstem
lesions on sound lateralization and brainstem auditory
evoked potentials. Hearing Research 68 1 , 73]88.
O. Olsson, S. Nielzen rPsychiatry Research 87 1999 65]75
Middlebrooks, J.C., 1988. Auditory mechanisms underlying a
neural code for space in the cat’s superior colliculus. In:
Edelman, G.M., Gall, E.W., Cowan, W.M. Eds. , Auditory
Function. Neurobiological Bases of Hearing. A Neuro-
sciences Institute Publ., Wiley Interscience, New York.
Nielzen, S., 1982. Music, Mind and Mental Illness. Doctoral
thesis. Lund, Sweden.
Nielzen, S., Olsson, O., 1997. Perceputal grouping due to pitch
and amplitude in hallucinating schizophrenics. Psy-
chopathology 30, 140]148.
Schreiner, C.E., Langner, G., 1988. Coding of temporal pat-
terns in the central auditory nervous system. In: Edelman,
G.M., Gall, E.W., Cowan, W.M. Eds. , Auditory Function.
Neurobiological Bases of Hearing. A Neurosciences Insti-
tute Publ., Wiley Interscience, New York.
Smith, G.J.W., Ruuth, E., Franzen, G., Sjoholm, L., 1972.
Intermittent regressions in a serial afterimage experiment
as signs of schizoprenia. Scandinavian Journal of Psy-
chology 13, 27]33.
Steinberg, R., 1986. Musikpsychopathologie. Musikalischer
Ausdruck und Psychische Krankheit. Doctoral thesis.
Munchen, Germany.
Steinberg, R., Flesch, M., Ghunter, W., 1998. Psychophysiolog-
ical remarks on hallucinations with special attention to
music. In: Nielzen, S., Olsson, O. Eds. , Clinical Psychoa-
coustics-Schizophrenia. Lund University Press, Lund, Swe-
Yin, T.C.T., Chan, J.C.K., 1988. Neural mechanisms underly-
ing interaural time sensitivity to tones and noise. In: Edel-
man, G.M., Gall, E.W., Cowan, W.M. Eds. , Auditory
Function. Neurobiological Bases of Hearing. A Neuro-
sciences Institute Publ., Wiley Interscience, New York.
Yost, W.A., Dye, R.H., 1991. Properties of sound localization
by humans. In: Altschuler, R.A. et al. Ed. , Neurobiology
of hearing. The Central Auditory System. Raven Press,
Ltd., New York, pp. 389]410.
Walter, H., Podreka, I., Steiner, M., Suess, E., Benda, N.,
Hajji, M., Lesch, O.M., Musalek, M., Passweg, V., 1990. A
contribution to classification of hallucinations. Psy-
chopathology 23, 97]105.
Warren, W.M., Bashford, J.A., 1976. Auditory contralateral
induction: an early stage in binaural processing. Perception
and Psychophysics 20 5 , 380 ]386.
... Algunos estudios han evidenciado que los pacientes que tienen esquizofrenia podrían procesar los estímulos acústicos de una manera inusual o alterada a nivel del tallo cerebral [22][23][24][25][26][27][28][29][30][31][32] . ...
... Sin embargo, a pesar de la abundante evidencia sobre esta disfunción, los resultados aún son equívocos. Contradictoriamente, algunos estudios han obtenido resultados normales 24,25 , mientras otros han detectado alteraciones, como, por ejemplo: ausencia de ondas, aumento de latencias, disminución de amplitudes, e incluso ausencia total de respuestas [26][27][28][29] . Curiosamente, se han asociado ABR anormales con la presencia de alucinaciones auditivas 28 , un síntoma distintivo en la mayor parte de los pacientes esquizofrénicos 30 . ...
Full-text available
La esquizofrenia es un trastorno mental crónico que afecta aproximadamente al 1% de la población mundial. Diagnosticar este trastorno se puede tornar difícil debido a que los criterios diagnósticos son complejos y sus síntomas se pueden presentar en una gran variedad de formas. Por lo tanto, se hace necesario contar con herramientas que ayuden a los médicos en su esfuerzo por diagnosticar este trastorno rápida y objetivamente. Algunos estudios han mostrado que estos pacientes podrían procesar los estímulos acústicos de una manera alterada a nivel subcortical. Sin embargo, a pesar de la abundante evidencia neurofisiológica sobre esta disfunción, los resultados aún son equívocos. En este trabajo se realiza una revisión exhaustiva de la literatura donde se abordan los resultados de los diferentes estudios neurofisiológicos publicados sobre el tema, así como las posibles causas de sus diferencias. Y por último, se analizan futuras técnicas, así como el impacto que tendrían en la práctica clínica en caso de ser validadas.
... Although the majority of tone-matching studies have investigated pitch discrimination, similar deficits are observed for detection of intensity (Donde et al., 2020a;Holcomb et al., 1995;Jonsson and Sjostedt, 1973), duration (Donde et al., 2020a;Jonsson and Sjostedt, 1973), or location (Matthews et al., 2013;Olsson and Nielzen, 1999;Perrin et al., 2010;Perrin et al., 2018). In one study that utilized the Montreal Battery for Assessment of Amusia (Kantrowitz et al., 2014b), 45% of participants with schizophrenia were classified as "amusical" vs. 9% of healthy comparison individuals. ...
Schizophrenia is a major mental disorder that affects approximately 1% of the population worldwide. Cognitive deficits are a key feature of the disorder and a primary cause of long-term disability. Over the past decades, significant literature has accumulated demonstrating impairments in early auditory perceptual processes in schizophrenia. In this review, we first describe early auditory dysfunction in schizophrenia from both a behavioral and neurophysiological perspective and examine their interrelationship with both higher order cognitive constructs and social cognitive processes. Then, we provide insights into underlying pathological processes, especially in relationship to glutamatergic and N-methyl-D-aspartate receptor (NMDAR) dysfunction models. Finally, we discuss the utility of early auditory measures as both treatment targets for precision intervention and as translational biomarkers for etiological investigation. Altogether, this review points out the crucial role of early auditory deficits in the pathophysiology of schizophrenia, in addition to major implications for early intervention and auditory-targeted approaches.
... Additionally, several strands of evidence show that non-verbal basic auditory functions are also impaired in SZ. For instance, patients present with large significant disturbances in tone-matching tasks consisting of discriminating non-verbal sounds according to their psychoacoustic features, such as pitch (Donde et al., 2017;Donde et al., 2019), location (Olsson and Nielzen, 1999), intensity (Holcomb et al., 1995) and dynamic streaming (McLachlan et al., 2013) perception. Critically, such basic perceptual impairments can lead to misinterpretation of the social intent conveyed through speech prosody (Leitman et al., 2010). ...
Patients with schizophrenia (SZ) display deficits in both basic non-verbal auditory processing and source-monitoring of speech. To date, the contributions of basic auditory deficits to higher-order cognitive impairments, such as source-monitoring, and to clinical symptoms have yet to be elucidated. The aim of this study was to investigate the deficits and relationships between basic auditory functions, source-monitoring performances, and clinical symptom severity in SZ. Auditory processing of 4 psychoacoustic features (pitch, intensity, amplitude, length) and 2 types of source-monitoring (internal and reality monitoring) performances were assessed in 29 SZ and 29 healthy controls. Clinical symptoms were evaluated in patients with the Positive And Negative Syndrome Scale Compared to the controls, SZ individuals in showed significant reductions in both global basic auditory processing (p<.0005, d=1.16) and source-monitoring (p<.0005, d=1.24) abilities. Both deficits correlated significantly in patients and across groups (all p<.05). Pitch processing skills were negatively correlated with positive symptom severity (r=-0.4, p<.05). A step-wise regression analysis showed that pitch discrimination was a significant predictor of source-monitoring performance. These results suggest that cognitive mechanisms associated with the discrimination of basic auditory features are most compromised in patients with source-monitoring disability. Basic auditory processing may index pathophysiological processes that are critical for optimal source-monitoring in schizophrenia and that are involved in positive symptoms.
... In the 1990s, our studies on automatic grouping of complex sound stimuli [3] showed that individuals with the diagnosis of schizophrenia reported aberrant perception of complex psy- choacoustic test sounds (auditory illusions) such as discontinuous streaming of tones [4], continuity illusion [5], and contralateral induction [6]. The aberrances indicate a disturbance of automatic sorting in the midbrain of schizophrenics. ...
This is from a book on acoustical, psychophysiological and perceptual aspects with a focus on biological methods to date.
... Prior studies have suggested that patients suffering from schizophrenia and ADHD may process certain sound stimuli in the brainstem in an unusual or aberrant manner [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Some studies have suggested that when these patient groups have been examined with brainstem audiometry, the resulting brainstem audiograms have displayed illness-specific aberrations [9,14,17,21]. ...
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Psychiatric disorders, such as schizophrenia, attention deficit hyperactivity disorder (ADHD), and bipolar disorder, may sometimes be difficult to diagnose. There is a great need for a valid and reliable diagnostic tool to aid clinicians in arriving at the diagnoses in a timely and accurate manner. Prior studies have suggested that patients suffering from schizophrenia and ADHD may process certain sound stimuli in the brainstem in an unusual manner. When these patient groups have been examined with the electrophysiological method of brainstem audiometry, some studies have found illness-specific aberrations. Such aberrations may also exist for patients suffering from bipolar disorder. In this study, we will examine whether the method of brainstem audiometry can be used as a diagnostic tool for patients suffering from schizophrenia, ADHD, and bipolar disorder. The method includes three steps: (1) auditory stimulation with specific sound stimuli, (2) simultaneous measurement of brainstem activity, and (3) automated interpretation of the resulting brain stem audiograms with data-based signal analysis. We will compare three groups of 12 individuals with confirmed diagnoses of schizophrenia, ADHD, or bipolar disorder with 12 healthy subjects under blinded conditions for a total of 48 participants. The extent to which the method can be used to reach the correct diagnosis will be investigated. The project is now in a recruiting phase. When all patients and controls have been recruited and the measurements have been performed, the data will be analyzed according to a previously arranged algorithm. We expect the recruiting phase and measurements to be completed in early 2015, the analyses to be performed in mid-2015, and the results of the study to be published in early 2016. If the results support previous findings, this will lend strength to the idea that brainstem audiometry can offer objective diagnostic support for patients suffering from schizophrenia, ADHD, and bipolar disorder. A positive result from the study could imply that brainstem audiometry could become an important supportive tool for clinicians in their efforts to diagnose patients with these disorders in a timely and accurate manner. NCT01629355; (Archived by WebCite at
... Sensory processing difficulties have been widely reported in schizophrenia, and particularly impaired auditory sensory processing is a prominent feature in schizophrenia (Rabinowicz et al., 2000;Javitt, 2009). Psychoacoustic phenomena such as streaming, i.e., organizing the sounds into "streams" (Nielzén and Olsson, 1997), restoration of missing sounds (Olsson and Nielzén, 1999b), and contralateral induction (Olsson and Nielzén, 1999a), where the perception of a sound's localization is affected by a second sound, have previously been shown by this group to be abnormal in schizophrenic patients. Schizophrenic patients also exhibit abnormalities in several auditory event-related potential (ERP) measures. ...
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Individuals diagnosed with schizophrenia show deficiencies of basic neurophysiological sorting mechanisms. This study further investigated this issue, focusing on the two phenomena, laterality of coding and auditory forward masking. A specific audiometric method for use in psychiatry was the measuring set up to register brain stem audiograms (ABRs). A sample of 49 schizophrenic patients was compared with three control groups consisting of healthy reference subjects (n=49), attention deficit hyperactivity disorder (ADHD) patients (n=29), Asperger syndrome (AS) patients (n=13) and drug-induced psychotic patients (n=14). Schizophrenic patients showed significant abnormal laterality of brainstem activity in wave II of the auditory brainstem response (ABR) in comparison with all other study groups. Forward masking effects in the superior olive complex were coded significantly differently by schizophrenic patients compared to control groups except for the AS group. The results suggest deficits in the coding of auditory stimuli in the lower parts of the auditory pathway in schizophrenia and indicate that increased peripheral lateral asymmetry and forward masking aberrances could be neurophysiological markers for the disorder.
... Clark et al., 2002). Because low TPJ activity among schizophrenia patients was only observed during the monaural stimulus conditions, it may be the case that lower right TPJ activity among schizophrenia patients indexes a more general problem with auditory localization abilities among these patients, especially those with auditory hallucinations, a symptom that characterized the present patient samples (Olsson & Nielzen, 1999). ...
Schizophrenia patients have abnormalities of auditory information processing, theoretically associated with dysfunction of neuronal excitation. Auditory paired-stimuli (S1-S2) paradigms are used to evaluate the nature of these abnormalities. It is unknown whether patients' abnormalities during S1-S2 paradigms are attributable to specific hemispheric differences in cortical processing. The present studies used whole head magnetoencephalography and monaural or binaural versions of the paired-stimuli paradigm to evaluate auditory processing among 38 schizophrenia and 38 normal subjects. The strengths of auditory-evoked brain responses over time were quantified using distributed source reconstructions with L2 minimum norm constraint and realistic head models. For left ear stimuli, schizophrenia and normal groups did not differ on either left or right hemisphere activity over auditory cortex. For right ear and binaural stimuli, schizophrenia patients had less activity over left auditory cortex from 80 to 120 ms post-stimulus but did not differ from normal on activity over right auditory cortex. Additionally, in response to monaural stimulation, schizophrenia patients had significantly less activity than normal over right temporal parietal junction from 60 to 120 ms post-stimulus. These data are consistent with four propositions about schizophrenia: (i). right auditory cortex is functioning normally; (ii). processing of simple auditory stimuli is abnormal in left auditory cortex, probably specifically in supra-granular layers; (iii). auditory localization abilities are deficient; and (iv). auditory cortex abnormalities are not a function of deficient hemispheric communication because they are evident early in processing as long as stimuli are delivered directly to left hemisphere.
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The purpose of the present study is to try an alternative way of analyzing the ABR (Auditory Brainstem Response). The stimuli were complex sounds (c-ABR) as used in earlier studies. It was further aimed at corroborating earlier findings that this method can discriminate several neuropsychiatric states. Forty healthy control subjects, 26 subjects with the diagnosis schizophrenia (Sz) and 33 with ADHD (Attention deficit hyperactivity disorder) were recruited for the study. The ABRs were recorded. The analysis was based on calculation of areas of significantly group different time spans in the waves. Both latency and amplitude were thereby influential. The spans of differences were quantified for each subject in relation to the total area of the curve which made comparisons balanced. The results showed highly significant differences between the study groups. The results are important for future work on identifying markers for neuropsychiatric clinical use. To reach that goal calls for more extensive studies than this preliminary one.
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Binaural interaction was studied using headphones presenting signals (tones or filtered speech) to one ear and noises of various spectral compositions to the other. Every half-second, the sides receiving the signal and noise were reversed. The noise was always perceived to alternate from side to side, but the signal appeared to be stationary and diffusely localized about the midsaggital plane when the noise contained the spectral components of the signal at appropriate intensity levels. This delateralization of a monaural signal results from a process called “contralateral induction” (CI). Additional observations indicate that CI corresponds to an early stage in binaural interaction which generally escapes notice because of further perceptual processing.
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This experiment examined the hypothesis that schizophrenics are less able than normals to make use of information concerning self movement when performing auditory localization tasks, and, therefore apply an alternative localization strategy, probably involving use of the pinnae. In this study three groups (healthy controls, schizophreniform patients and chronic schizophrenics) were compared in four experimental conditions: (1) head-movement and free pinnae; (2) static head and free pinnae; (3) head movement and covered pinnae; and (4) static head and covered pinnae. All subjects perform better with head movement than without it, with pinnae than with covered ones. Schizophreniform patients were affected more than normals by pinnae covering. This difference did not reach significance when normals were compared with chronic schizophrenics. A pronounced susceptibility to pinnae manipulation, correlated with medication level, appeared in the combined patient group in the moving condition. It was suggested that schizophreniform subjects, as compared to healthy controls are more depended on pinnae generated information for auditory localization and less able to compensate for its absence with movement generated information. The possibility that the effect is related to psychosis as such, rather than to schizophrenia in particular, was considered.
Although a sufficiently intense noise in one ear will mask speech heard in the contralateral ear a weaker noise has the opposite effect: it enhances the loudness of speech heard in the other ear. Procedure: one earphone is used to introduce speech at a constant intensity into one ear. Another earphone introduces a white noise into the other ear. The listener first listens to the speech heard monaurally (ear 1) with no noise in the contralateral ear (ear 2). If noise is now introduced into ear 2, the loudness of speech heard in ear 1 increases. Most listeners report a change in the localization of the speech: it is localized nearer to the center of the head when noise is introduced into the opposite ear. This paper concerns these phenomena.