Case study on Auditory Verbal Hallucinations

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