The functional importance of age-related differences in temporal processing

Transcription

1 Kathy Pichora-Fuller The functional importance of age-related differences in temporal processing Professor, Psychology, University of Toronto Adjunct Scientist, Toronto Rehabilitation Institute, University Health Network Guest Professor, Linneaus Centre HEAD, Linköping University, Sweden Funded by CIHR, NSERC, & Hearing Foundation of Canada

2 Outline 1. Types of presbycusis 2. Auditory temporal processing 3. Implications for assessment and treatment

3 Prevalence of Hearing Loss in Older Adults Audiometry (e.g., Plomp, 1978; Moscicki et al., 1985; Willott, 1991) 65 years 24% 70 years 30% 75 years 50% years 83% 75% of people with hearing loss are > 75 years old Average first time hearing aid user ~ 70 years

4 Audiograms and Age (ISO 7029) Women Men 3kHz 3kHz HF audiometric threshold elevation OHC (also noise-induced hearing loss) Endocochlear potentials ~ stria vascularis Neural loss of synchrony (Mills, Schmeidt, Schulte, & Dubno, 2006)

5 Speech Understanding in Noise Little problem in ideal listening conditions Quiet One talker Familiar person, topic, situation Simple task, focused activity Difficulty in challenging listening conditions Noise Multiple talkers Strangers, accents, new topic, novel situation Complex task, many concurrent activities Fast pace Hearing aid Avoid by withdrawal from social interaction!

6 Listening by an older adult: Lived experience of hearing loss for me, distinct enunciation helps greatly, in completely sounding each word, the speaker goes more slowly and therefore gives the recipient time to assimilate and adapt the sounds to meaning when asking for repetition of statements it seems to be a way of giving the brain cells time to put sounds into meaning using a photographic term, I have a very shallow depth of field and sounds are soon out of focus most TV or radio speakers are too fast and while I am trying to make sense of the first statement they are away onto the third or fourth sentence so I soon have to drop out and so lose interest I can appreciate young children being considered inattentive or disruptive in school from this lack of hearing and assimilation and not comprehending why because they don t know that they can t hear

7 Annual Publications Auditory Temporal Processing and Aging , , , ,25 0,

8 Reasons for Increased Research Cognitive hearing (neuro)science (SJP, 2009) Connect ear to brain (physiology) Connect hearing to listening (psychology) Attention, memory, speed of processing, cross-modal integration Ecology vs psychophysics Speech/music/complex auditory scenes Overcome bias to cochlear/spectral account of HL Technology Research tools (fmri, ERP, eye tracking) Opportunities in technology design (DSP) Demographics of aging

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13 Questions & Directions Does adult aging affect temporal processing at one or more levels? How are age-related deficits in temporal processing related to speech processing (in noise)? Need to differentiate sub-types of presbycusis based on temporal processing?

14 Speech as a Signal: Temporal Cues Syllabic patterns prosody (speech rate, rhythm) Onsets/offsets or gaps/durations phonemic contrasts (apple al) Synchrony/periodicity cues fundamental frequency & harmonic structure (voice pitch, quality)

15 Levels of Temporal Processing (Pichora-Fuller & Macdonald, ISAAR, 2007) Cue Type Periodicity (synchrony; phase) Gaps/durations (onsets/offsets) Envelope (modulation) Role in Speech Voice (quality, identity, clarity, segregation) Phonemic contrasts (stops, VOT) Prosody (rate, rhythm, stress) Experimental Measures Psychoacoustic Frequency DL MLD FM modulation High-level intensity DL Gap detection Duration discrimination AM modulation Speech F 0 DL Speech MLD Identification of concurrent vowels, jittered speech Discrimination of phonemes, words Intelligibility of noise-vocoded, compressed speech Tonality in music

16 Periodicity or Synchrony

17 Periodicity Voice Cues

18 Phase-locking TIMING of auditory nerve 90 degrees of input cycle for a pure tone Stable over level Stable over place if input when activation is widespread for high levels of input Compensates for imprecision of place coding when input levels are high and input has multiple frequencies

19 Phase Locking Periodicity Coding

20 Place and Timing of Firing ~ Signal Frequency

21 Spectral vs Temporal Speech Cues

22 Speech on Speech Listening

23 F 0 Separation & Concurrent Vowel Identification (Vongpaisal & Pichora-Fuller, JSLHR, 2007) Note: F 0 DL: Younger =.6 Hz vs Older = 1.8 Hz (F 0 = 120, 122, 124, 127, 135, 151 Hz)

24 Individual Differences Voice Younger Older

25 Melodic Perception

26 Lowest harmonic

27 Proportion of 60 trials correct Harmonics & Tonality (Russo, Ives, Goy, Pichora-Fuller, & Patterson, Ear & Hearing, 2012) 1 0,9 6 Typical Older Adults 3 High Performing Older Adults 6 Younger Adults 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0, Average lowest component

28 Proportion of 60 trials correct Individual Differences - Tonality 1,2 6 Typical Older Adults 3 High Performing Older Adults 6 Younger Adults 1 0,8 0,6 0,4 0, Average lowest component

29 Emotion

30 Emotion and Voice Pitch (Dupuis, Pichora-Fuller, van Lieshout, submitted) Voice F 0 DL correlated with recognition accuracy r = -.68 (p <.01) PTA not significantly correlated

31 Temporal Jitter Simulation

32 Loss of Neural Synchrony Hypothesis Basilar Membrane Displacement Neuron Firing Time Aging results in more error in phase locking (poorer synchrony or jitter ) Consider as if mild form of auditory neuropathy

33 Jittering a Tone or Speech (Pichora-Fuller, Schneider, MacDonald, Brown, & Pass, 2007, Hearing Research)

34 Jittered Example Intact Jittered

35 Jittered and Intact SPIN Sentences (Jittered below 1.2 khz only; random delays based on noise with SD =.25ms, BW = 500Hz)

36 Effect of Jitter on Word Identification

37 Intact & Jittered Concurrent Vowels (Anselmo, Pichora-Fuller, & Vongpaisal, in preparation)

38 Gap Detection

39 Non-speech Gap Detection (Schneider, Pichora-Fuller, Kowalchuk & Lamb, 1994)

40 Gap-detection threshold (ms) Musicians Ben Zendel s PhD Musician Non-musician Age (years)

41 Speech-in-noise threshold (db) Musicians Ben Zendel s PhD Musician Non-musician Age (years)

42 Gap Size for Stop Consonants (Haubert & Pichora-Fuller, 1999) Cash vs Catch Vary size of inserted gap and ask which word of the pair is heard Older listeners need longer gap to hear [t] Longer gaps in slower speech

43 Relating Gap Detection to Speech Perception

44 Types of Gap Detection (following Phillips, 1997) Within - channel case 2-5 ms detection thresholds peripheral processes perform discontinuity detection with in a given channel Between - channel case ms thresholds relative timing operations requiring higher cognitive processes assumed

45 Spectral Nature of Markers (Pichora-Fuller et al., JASA, 2006) Within vs between-band composition? Vowels like tones Consonants like band-pass noise Within-band gap detection should be like in #V_V# words (e.g., [upu]) Between-band gap detection should be like #C_V# words (e.g., [spu])

46 Short (40 ms) Long (250 ms) Non-speech Symmetrical Asymmetrical Speech Symmetrical Asymmetrical (Pichora-Fuller, Schneider, Benson, Hamstra, & Storzer, JASA, 2006)

47 Non-speech, Long Marker, Spectrally symmetrical 250ms marker 10ms gap

48 Non-speech, Long Marker, Spectrally Asymmetrical 250ms marker 10ms gap

49 Gap Detection Threshold (msec) Gap Detection Threshold (msec) 8 Pichora-Fuller, Schneider, Benson, Hamstra & Storzer, 2006 JASA 6 young adults old adults children 4 2 Symmetrical short speech long speech short non-speech long non-speech Speech young adults old adults children Nonspeech Asymmetrical 0 short speech long speech short non-speech long non-speech

50 Gap Detection Threshold (msec) Jittered Gap Detection: Symmetrical Long-duration Markers (extended from Pichora-Fuller, Schneider, Benson, Hamstra & Storzer, 2006, JASA) 8 6 young adults old adults jittered long speech long non-speech Speech Nonspeech

51 Envelope

52 P ROPORTION CORREC T Words Blocked by Number of Bands (Sheldon, Pichora-Fuller, & Schneider, 2008) Age differences Young: 6.1 vs Old: 8.6 bands.8.6 No training effect (filled vs open) NUMBER OF BANDS

53 Aging vs Neural Presbycusis? Temporal measures not correlated with audiogram (but audiograms good) OAEs normal? Age-related group differences at all levels of temporal processing Psychoacoustics and speech, tonality, emotion measures concur Are problems related or independent? Minority of older adults perform like younger adults Individual differences correlations across measures? Differential diagnosis Prevalence of neural presbycusis (similar approach as auditory neuropathy)?

54 Threshold (db HL) Within-subjects Test Battery Frequency (khz) 0,25 0,5 1 1, ,2 12,5 48 Older Adults Min Mean Max 72 yrs old (66-81) Audiologic < 25 dbhl (.25-3 khz) HF audiometry OAEs Speech (e.g., SNR, TC) Psychoacoustic F0 DL Within-channel gap Between-channel gap AM

55 Questions & Directions Does aging affect temporal processing at one or more levels? All levels of temporal processing may be reduced Age correlates with PTA4,6,8; gap detection (between channel: BBN_tone), AM Correlations between gap and AM (envelope cues) No strong correlations between F0 and gap or AM No strong correlations between temporal measures and PTA Three factors: fine structure (F0) envelope (gap, AM) PTA4,6,8

56 Questions & Directions How are age-related deficits in temporal processing related to speech processing (in noise or distortion)? Simple correlations (N = 48): -15 SNR ~ AM, PT(4,6,8), PTA Regression (N = 48): -15 SNR ~ PTA4,6,8

57 Questions & Directions Need to differentiate sub-types of presbycusis related to temporal processing? DPOAE PTA 4,6,8 Normal Not TOTAL Normal Not Unknown 2 5 TOTAL SNR Normal OAE: correlation with AM (p =.02) Abnormal OAE: best correlation with PTA 4,6,8 (p =.07) Musical tonality: F 0

58 Summary Most (but not all) older adults (who have clinically normal audiograms below 4 khz) have sub-clinical auditory processing deficits at various levels of coding temporal cues (periodicity, onset-offset, envelope) Temporal distortion reduces performance of young on various tasks: Concurrent vowel identification, speech in noise, gap detection There are probably at least three relevant auditory factors: fine structure (F0) envelope (gap, AM) PTA4,6,8 Each type of processing may play a specific role depending on Type of signal(s) F0 for music AM for speech in noise Type of pathology PTA 4,6,8 if OHC damage (abnormal OAEs) AM if neural damage (normal OAEs)

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