Reine Worttaubheit

(Subkortikal sensorische Aphasie, pure word deafness)

Case study

Patient W.H.

  • male; 70; manager; multilingual:
  • German (native)
  • Spanish (30 years Venezuela)
  • English (10 years USA)

Symptoms

  • auditory comprehension and repetition of heard speech greatly limited
  • audiometric tests - normal
  • comprehension of non-verbal auditory stimuli - normal
  • the ability to speak, read and write - unaffected
  • tendency to (unconciously) use lip-reading as an aid in auditory comprehension (careful observation of the face of the examiner)
  • auditory comprehension is variant and context-related: it is superior when the patient introduces the subject of conversation himself, and it drops drastically when the examiner suddenly changes the topic
  • isolated words are less easily identified than words embedded in sentences

Speech samples

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Tests

The following tests were applied 1 month, 6 months, 8 months and 12 months post onset:

  1. Phoneme discrimination test (forty item CV test)
    • 20 identical pairs (e.g. /ta/ /ta/)
    • 10 phon. distant pairs (3 feature difference)
    • 10 phon. close pairs (1 feature difference)

    W.H.'s performance (69% - 73% correct) well below lower end of the normal range for his age group (89%). The results were stable over all 4 tests.

  2. Phoneme restoration test

    14 short stories with an appropriate and an inappropriate conclusion expressed by a minimal pair (e.g. klettern - kleckern). Word frequency, word length, phoneme class, and the position for the restored phoneme were varied. Signal editing: whole phoneme deleted, burst deleted, transition deleted, only the transient present.

    Controls follow auditory cues (if any), W.H. follows only the contextual cues. The results were stable over all 4 tests.

  3. Bimodal perception test (McGurk effect)
    • 5 synthetic auditory syllables (/ba/.../da/) are combined with 5 synthetic visual syllables (/ba/.../da/) = 25 stimuli
    • In addition audible and visible speech is presented alone = 10 stimuli
    • 35 stimuli in six random sequences

    W.H. relies on visible speech, controls rely on both types of cues. The results were stable over all 4 tests.

  4. Intonation (Lx) perception test

    F0 cues (Lx signal) for male voice, female voice, assertion, question, verification, topic change, aspect change, agreement, dissonance, etc., were presented in 6 random sequences.

    W.H. identifies the intonational cues to discourse structure much better than the controls do (e.g. topic change 67% W.H. - 24% C.). The results were stable over all 4 tests.

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