A framework for understanding speech disorders

1
A framework for understanding speech
disorders Dr Alexander Leff
2

• Plan
• Minimal anatomical and linguistic theory
• Clinical examination of language function
• Errors to look out for
• Clinical cases (videos and scans)

3
Anatomy boxes and sticks
Wernicke-Lichtheim model (1874) Popularized by
Geschwind (1970, 1985) Connectionism A
auditory language area M motor language area B
concept area (ideation)
4
Transcortical Motor aphasia
Transcortical Sensory aphasia
Wernickes aphasia
Brocas aphasia
Conduction aphasia
Pure word deafness
Speech apraxia
5
Boxes and sticks projected onto the brain
6
Processes involved in speaking
Concept generation and retrieval of its
representation
Phonology and articulation
7
Processes involved in speaking
Aphasia (present regardless of output mode)
Articulatory Speech apraxia, dysarthria,
dysphonia, (only a problem when speaking)
8

• Nomenclature
• Broca output motor production.
• Wernicke input sensory perception.
• All aphasic patients have a problem with speech
  production (errors vary).
• Even Broca-type patient have problems
• comprehending complex sentences.

9
Examination

• Speech output
• Spontaneous/picture description
• Naming
• Repetition
• Automatic (counting)
• Auditory input
• 1st, 2nd and 3rd order commands
• Writing
• Reading

10
What to look for

• Speech output
• Volume (high, normal or low).
• Agrammatic/telegraphic (function words missing).
• Meaningful (semantic content)?
• Speech error types
• Phonemic (cat ? cap)
• Semantic (cat ? dog)
• Jargon (cat ? ???)
• Visual errors
• Perseverations

11
(No Transcript)
12
Cases
13
Case A Video
14
Case A
15
Case B
Cognitive ? gestural object use (limb
apraxia) Digit span ? 3 Naming ? (semantic
errors) Repetition ? Comprehension ? (SW and
complex sentences) Writing ? Reading ?
16
Case B Video I Video II
17
Case B
L
18
Case C Video
19
Case C
Cognitive normal Digit span normal
5 Naming mildly ? Repetition mod ? (OK for
non-words) Comprehension mildly ? at sentence
level Writing normal Reading normal
20
Case C
L
21
Case D Video
22
Case D
Cognitive normal Digit span 7 Naming mildly
impaired Repetition ?? Comprehension slow
but correct Writing ? left school
early Reading ? left school early
23
Case D
L
1. Left SLF
2. Right MCP
3. Left post insula
24
Case E Video
25
Case E
Cognitive ? gestural object use Digit span 6
(normal) Naming ?? v. poor (sem and phon
errors) Repetition ? poor Comprehension ? at
sentence level Writing ? mild (picture
description) Reading ? all word types,
especially non-words
26
Case E
L
27
Case F Video
28
Case F
Cognitive normal Digit span 7
(normal) Naming normal Repetition normal Compr
ehension normal Writing normal Reading ? mild
29
Case F
30

• Conclusions
• Language testing is not difficult
• Why is it hard to predict lesion site from
  behaviour?
• Input and output classification is a
  misnomer
• Clinically and experimentally not enough
  emphasis on error types
• Wernicke-Lichtheim model has its uses
• More so for behaviour than brain models of
  language
• Look out for more complex lesion overlap maps