Auditory deficits Day 11

1. Auditory deficitsDay 11 Brain & Language LING 411/412/489 NSCI 411/611/489/689 Harry Howard Tulane University

2. Q3

3. Q3 answers • A phonological feature is a representation of (a) the articulation of a speech sound, (b) the perception of a speech sound, or (c) both (a) and (b). • A formant is part of the acoustic properties of a (a) consonant or (b) vowel. • The fundamental frequency is NOT (a) the basic frequency of the human voice that all others are built on, (b) the lowest band of energy in a vowel, or (c) higher on average in women than men. • Which is NOT a feature of vowels: (a) manner, (b) height, or (c) advancement (front/back)? • Which is NOT a feature of consonants: (a) place, (b) rounding, or (c) voicing? Brain & Language, Harry Howard, Tulane University

4. Q3 answers, cont. • Would you call the following model of speech comprehension (a) serial or (b) parallel? acoustic-phonetic analysis > sub-lexical processing > lexical-semantic access > comprehension • The flaw in the model in (6) claimed by Hickok & Poeppel (2004) is that (a) sub-lexical processing > acoustic-phonetic analysis, (b) there are patients who cannot perform sub-lexical processing tasks accurately, yet have normal comprehension, or (c) there are patients who cannot perform acoustic-phonetic analysis accurately and have abnormal comprehension. • We would expect to be in the ventral stream (a) the interface between sound and meaning, (b) the interface between sound and motor control, or (c) the basic sound codes. • We would expect to be in the dorsal stream (a) the interface between sound and meaning, (b) the interface between sound and motor control, or (c) the basic sound codes. • A double dissociation involves (a) a group of subjects that performs inaccurately on task A but not task B, (b) one group of subjects that performs inaccurately on task A but not on task B and another group of subjects that performs inaccurately on task B but not on task A, or (c) a group of subjects that performs inaccurately on both tasks A and B. Brain & Language, Harry Howard, Tulane University

5. Course administration • Course home page • http://www.tulane.edu/~ling/LING411/ • Readings are found: • MyTulane > BrainLanguage_CC: Brain and Language(Combined) > Course Documents • Public Service tasks Brain & Language, Harry Howard, Tulane University

6. Polster & Rose (1998)

7. Abstract • This article examines four disorders of auditory processing that can result from selective brain damage in an effort to derive a plausible functional and neuroanatomical model of audition. • The article begins by identifying three possible reasons why models of auditory processing have been slower to emerge than models of visual processing: • The four auditory disorders are then reviewed and current theories of auditory processing considered. • Taken together, these disorders suggest a modular architecture analogous to models of visual processing that have been derived from studying neurological patients. Brain & Language, Harry Howard, Tulane University

8. Four disorders of auditory processing • Cortical deafness • Pure word deafness • Auditory agnosia • Phonagnosia Brain & Language, Harry Howard, Tulane University

9. Reasons for delay in development of models of auditory processing • Neuroanatomical differences between the visual and auditory systems • the auditory system has a neuroanatomical redundancy built into it: it transmits information about sound in all parts of space to both hemispheres, rather than to one • result: disorders of auditory processing are quite rare • dichotic listening tasks are less informative than visual-half field presentation • diagnostic difficulty caused by the close relationship between speech comprehension and auditory processing • Terminological confusions relating to auditory processing disorders • “verbal processing” can conflated with “auditory processing” • Technical factors that have made auditory stimuli more difficult to study than visual stimuli Brain & Language, Harry Howard, Tulane University

10. Cortical deafness • Wernicke and Friedlander (1883) described a patient who was unable to hear any sounds, but had no apparent damage to the hearing apparatus and labelled the disorder cortical deafness. • One review of the literature, reported “only 12 cases of significant deafness due to purely cerebral pathology” (Graham, Greenwood & Lecky, 1980:43) • Identifying cases of cortical deafness has proved to be difficult for several reasons. • patients rarely suffer bilateral lesions in the critical region of auditory cortex in the lateral temporal lobes • some patients believed to suffer from cortical deafness may, in fact, suffer from auditory inattention or neglect • cortical deafness is often transient, resolving to a less severe, or more specific, auditory processing disorder such as pure word deafness or auditory agnosia Brain & Language, Harry Howard, Tulane University

11. Agnosia overview • Agnosia: an impairment in which a patient fails to recognize a stimulus in a sensory modality, although perception in the modality is unimpaired • Audition • auditory agnosia • pure word deafness (auditory-verbal agnosia) • phonagnosia • Vision • visual agnosia: normal vision, can’t recognize objects • alexia (word blindness): normal vision, can’t recognize written language, i.e. can’t read • prosopagnosia Brain & Language, Harry Howard, Tulane University

12. Auditory agnosia • It is best defined as an inability to recognize auditorily presented sounds independent of any deficit in processing spoken language. • at times, it has been replaced by a more general definition refering to a deficit involving any type of auditory stimuli • It dates back to Freud (1891), but the first case of ‘pure’ auditory agnosia appears to have been reported only thirty years ago (Spreen et al., 1965). • They presented a patient who was severely impaired at identifying a variety of sounds such as coughing, whistling and a baby crying, but showed no evidence of impaired speech comprehension Brain & Language, Harry Howard, Tulane University

13. Pure word deafnessauditory-verbal agnosia • Kussmaul (1877) coined the term “pure word deafness” to refer to an inability to comprehend spoken words despite intact hearing, speech production and reading ability. • one patient complained that speech sounded “like a great noise all the time . . . like a gramophone, boom, boom, boom, jumbled together like foreign folks speaking in the distance” • another said: “I can hear you talking but I can’t translate it” • Examiner: What did you eat for breakfast? • Patient: Breakfast, breakfast, it sounds familiar but it doesn’t speak to me. (Obler & Gjerlow 1999:45) • The experience of word sounds appears to undergo a qualitative change, and some word deaf patients cannot judge the length of a word • However, some patients appear able to extract information about the speaker from their voice (i.e., sex, age, region of origin, or affective information) despite being unable to comprehend the spoken message • Despite this impairment in speech comprehension, these patients can be unimpaired at identifying non-linguistic sounds Brain & Language, Harry Howard, Tulane University

14. Phonagnosia • An impairment in the ability to recognize familiar voices, just as prosopagnosia reflects an impairment in the ability to recognize familiar faces (Van Lancker and Canter 1982) • subjects were asked to identify which of four names or faces matched a particular famous voice • Subsequent research produced evidence for a double dissociation between memory for familiar voices and the ability to discriminate between unfamiliar voices: • One group of patients performed normally on the discrimination task but was impaired on the memory task, • whereas another group of patients performed normally on the memory task, but was impaired on the discrimination task • Despite being unable to identify voices, patients suffering from phonagnosia appear to be able to understand speech and identify nonverbal sounds (Van Lancker and Kreiman, 1987). Brain & Language, Harry Howard, Tulane University

15. Summary Brain & Language, Harry Howard, Tulane University

16. Optic aphasia • A patient CANNOT name an object presented visually, • but the patient CAN … • name the object from a verbal description • describe the function of the object • sort pictures of objects into categories • so it is not visual agnosia. • Cause: impairment of pathway from visual object perception to semantic representation • the object’s semantic representation can be activated only enough for basic tasks, such as sorting, but not enough for naming Brain & Language, Harry Howard, Tulane University

17. Next time Lateralization of phonology - Myers §4