This document summarizes a case study examining the neural correlates of auditory verbal hallucinations (AVH) in schizophrenia. Two main hypotheses for AVHs are presented: 1) misinterpreted inner speech and 2) abnormal activation of the auditory cortex. fMRI was used to compare brain activation patterns in a patient experiencing AVHs and a control subject. The patient showed increased activation in auditory regions, supporting the second hypothesis that AVHs are linked to abnormal auditory cortex activation. The study provides evidence that areas activated during normal speech are also activated during AVH experiences.

1. Mark
Gronowski
A
Case
Study
on
Auditory
Verbal
Hallucina5ons
Monday, 29 April, 13

2. Auditory
Verbal
Hallucina5ons
(AVH)
• One
of
the
most
characteris4c
symptoms
of
Schizophrenia
• But,
why
do
they
occur?
• Two
hypotheses
exist:
• Misinterpreted
inner
speech
• Abnormal
ac4va4on
of
the
auditory
cortex
Monday, 29 April, 13

3. Hypothesis
1:
Misinterpreted
Inner
Speech
• AVH
occurrences
with
perioral
movements
• Perioral
ac4vity
is
generally
associated
with
inner
speech
• Inner
Speech
genera4on
ac4vates
Broca’s
area
• Misrecogni4on
of
inner
speech
also
associated
with
leK
Middle
Temporal
Gyrus
(MTG)
Monday, 29 April, 13

4. Hypothesis
2:
Abnormal
ac5va5on
of
the
auditory
cortex
• AVHs
also
linked
to
abnormal
ac4va4on
of
the
primary
auditory
cortex
(PAC)
• May
cause
experience
of
a
perceived
real
sound
leading
to
misinterpreta4on
of
its
source
as
external
•
Monday, 29 April, 13

5. Case
Study:
Pa5ent
DT
• Female
with
Paranoid
Schizophrenia
• Experienced
con4nuos
AVHs
• Single
voice
commen4ng
on
her
behaviour
• Ordered
her
to
accomplish
some
acts
• Some4mes
heard
mul4ple
voices
talking
to
each
other
• Trained
to
report
the
onset
and
end
of
her
AVHs
• Hallucina4ons
inhibited
by
loud
external
speech
Monday, 29 April, 13

6. Case
Study:
Control
Subject
• Matched
Control
Subject
• Both
right-­‐handed
females
• Matched
in
age
(36
years)
• Same
level
of
educa4on
(high
school)
Monday, 29 April, 13

7. fMRI
Tes5ng
• fMRI
(Func4onal
Magne4c
Resonance
Imaging)
• Measure
of
Blood
Oxygena4on
Level
Dependent
(BOLD)
change
• Experimental
Condi4on
• Listen
to
noise
generated
by
the
fMRI
scanner
• Control
Condi4on
• Listen
to
recorded
speech
through
headphones
Monday, 29 April, 13

8. Results:
Control
Subject
• BOLD
signal
response
to
External
Speech
(Control):
• LeK/Right
Middle
and
Superior
Temporal
Gyri
• LeK
Inferior
Temporal
Gyrus fMRI of audit
• fMRI
noise
(Experimental)
response:
• No
significant
ac4va4on
seen
in
the
temporal
lobes
Monday, 29 April, 13

9. 9
Left Hemisphere Right Hemisphere
External Speech / Control
Monday, 29 April, 13

10. Results:
Pa5ent
DT
• BOLD
signal
response
to
fMRI
noise
(Experimental):
• LeK
Superior
Temporal
Gyrus
(Auditory
Cortex)
• Right
Middle
Temporal
Gyrus
(Auditory
Associa4on
Cortex)
• No
significant
ac4va4on
in
Broca’s
area
fMRI of auditor
Monday, 29 April, 13

11. 11
Primary Auditory Cortex
Auditory Association Cortex
Left Hemisphere Right Hemisphere
AVH Response / DT
Monday, 29 April, 13

12. Analysis
• Increased
metabolic
ac4vity
in
PAC
• Consistent
with
abnormal
ac4va4on
of
PAC
• Defec4ve
leK
MTG
could
permit
access
of
internal
speech
to
the
PAC
• Consistent
with
misinterpreta4on
of
inner
speech
• Lack
of
ac4va4on
of
Broca’s
area
inconsistent
with
hypothesis
predic4on
• Type
II
error?
Monday, 29 April, 13

13. Contribu5ons
• Areas
ac4vated
by
normal
speech
in
healthy
individuals
are
also
ac4vated
by
the
experience
of
AVHs
• Hypotheses
not
mutually
exclusive
• Defec4ve
internal
monitoring
in
the
leK
hemisphere
may
be
associated
with
abnormal
ac4va4on
of
the
auditory
cortex
Monday, 29 April, 13