PATIENT SELECTION

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Hearing Problems in People with Spinocerebellar
Ataxia
Gary Rance (PhD)
SCA Australia Meeting, Nov 8, 2009
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Gary Rance

• Associate Professor The University of
  Melbourne
• Co-ordinator Master of Clinical Audiology
  program
• Wagstaff Research Fellow in Otolaryngology (Royal
  Victorian Eye Ear Hospital)

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Project Hearing Problems in People with SCA

• Part of a broader study of auditory function in
  listeners with neurodegenerative disease
• Friedreich ataxia (FRDA)
• Charcot-Marie-Tooth syndrome (CMT)
• Combined visual/auditory neuropathies
• Lebers Hereditary Optic Neuropathy (LHON)
• Autosomal Dominant Optic Atrophy (ADOA)

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Auditory Processing

• Looking for problems in the way sound information
  is transmitted from the ear to the brain
• Friedreich ataxia findings (2007 onwards)
• Normal sound detection
• Abnormal neural transmission
• Disrupted perception of speech (particularly
  in background noise)
• 30/30 FRDA subjects showed impaired speech
  understanding in everyday listening conditions

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Why Look for Hearing Problems in SCA patients?

• Many studies (Abele et al, 1997 Kumagi et al,
  2000 Perretti et al. 1996) have shown abnormal
  electrical responses in the auditory pathways of
  SCA patients (50-80 affected)
• None of these studies looked at auditory
  perception
• This project
• sound detection (standard hearing test)
• electrical responses (auditory brainstem
  response)
• auditory processing (timing cues)
• perception (speech understanding)
• habilitation

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Assessments

• Ethics approval from the RVEEH ethics committee
• Non-invasive
• Based on standard clinical tests
• Run from a laptop computer so the testing can be
  carried out at home if convenient

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Assessments Auditory Brainstem Response (ABR)

• Electrical responses to sound from the auditory
  pathway (brainstem)
• Measured via three sensors placed on the scalp
• Subject response nil
• Duration ? 20 minutes

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Auditory Brainstem Response (ABR)
V
III
V
I
III
Subject N8 (rarefaction)
I
III
I
V
0.5 ?V/Div



2
4
10
6
8
14
12
0
ms
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Auditory Brainstem Response (ABR)
V
III
V
I
III
Subject N8 (rarefaction)
I
III
I
V
I
III
FAABR (rarefaction)
V
(N14)
0.5 ?V/Div
FAAN (rarefaction)
CM

(N14)

FAAN (compression)
CM

(N14)
2
4
10
6
8
14
12
0
ms
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Assessments Auditory Processing

• Perception of temporal (timing) cues
• Aim to find the smallest change in a rapidly
  fluctuating sound that a listener can perceive
• Subject response indicate when able to hear a
  change in a constant sound
• Duration ? 20 mins

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Speech Perception in Quiet Background Noise
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Assessments Speech Perception

• CNC Word Test
• recorded speech in quiet and different levels of
  background noise
• Subject response imitation
• Duration ? 30 minutes

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Rance et al., (2008)
FAAN
20
5
10
0
Quiet
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Project Details

• Testing carried out by Master of Clinical
  Audiology Students
• Data collection March-August 2010
• Typically requires a single 1.5 hour session to
  test both ears
• Subjects - all welcome - particularly
  interested in SCA groups 1, 2 6