Larry E. Roberts

Department of Psychology, Neuroscience, and Behaviour McMaster University, Hamilton, Ontario, Canada;

Over the Horizon: 8th International TRI Tinnitus Conference

Auckland, New Zealand, March 10-13 2014

With appreciation to the Neurological Foundation of New Zealand and the New Zealand Tinnitus and Hyperacusis Network

TINNITUS RESEARCH

INITIATIVE

Neural Plasticity and Attention in Normal Hearing and in Tinnitus

Neural plasticity on this scale should be expressed in AEPs and AEFs

Recanzone et al. 1993

Frequency tuning

Tuning bandwidth

Spike rates

Response latency

Auditory Projection Pathway

Frontal/Temporal Cortex Oscillatory activity

Nonprimary Auditory Cortex N1, Ta, N1c, P2, N2

Primary Auditory Cortex MLRs, 40-Hz ASSR

Subcortical Structures FFRs ABRs

Intrinsic alertness network - Dosenbach et al 2006, 2007

Orienting top-down system and the cingulo-opercular task

maintenance network - Peterson and Posner 2102

Default mode network – Raichle 2001, 2010

Dorsal visual attention system - Corbetta and Schulman 2002

Three Topics:

(1) What are rules for plasticity and attention in normal hearing subjects?

(2) Are these rules changed in tinnitus?

(3) Sound therapy for tinnitus

Laboratory Training Professional Musicians

Bosnyak, Eaton, & Roberts (2004)

Cerebral Cortex 14:1088-l099.

Shahin, Bosnyak, Trainor, and Roberts

(2003) J. Neuroscience 23, 5545-5552.

P2 and N1c are Neuroplastic, N1 is not

2 kHz 40-Hz AM tone violin and piano tones

How We Study Acoustic Training

2000 Hz carrier AM @ 40 Hz

40-Hz Auditory Steady State Response (ASSR)

Amplitude and phase

ASSR sources localize tonotopically to A1

Group E Group C1

Amplitude of the ASSR is Modulated Attention ASSR Phase by Experience

Gander, Bosnyak, & Roberts (2010) Hearing Research 269:81-94

2000 Hz carrier AM @ 40 Hz

p = 0.016 p = 0.041

p = 0.0009

N1 amplitude

increased

with attention

but not with

experience

P2 amplitude

increased

on day 2, in

both groups

Subjects trained to detect

targets in a 2-kHz 40-Hz

AM sound

Alternating

active/passive blocks

Results Suggest These Principles for the Normal Hearing Adult Brain:

(1) Competitive interactions in A1 constrain cortical representations for trained sounds (ASSR Amplitude does not increase);

(2) Cortical representations in nonprimary cortex are more plastic (P2 and N1c amplitudes increase);

(3) The temporal response properties of neurons in A1 are modified by experience with sound (ASSR phase changes with sound exposure);

(4) Attention increases the neural population engaged during learning (ASSR and N1

amplitude increase);

(5) But attention is not required for auditory remodeling;

(6) Some neuroplastic effects are developmentally dependent (P2) and others not (ASSR phase);

(7) Modulation by attention is not expressed in AEPs until early adolescence.

Three Topics:

(1) What are rules for plasticity and attention in normal hearing subjects?

(2) Are these rules changed in tinnitus?

(3) Sound therapy for tinnitus

Almost everything changes, when training is given in the Tinnitus Frequency Region:

(1) ASSR Amplitude increases with training for a 5 kHz 4-Hz AM sound;

(2) Changes in ASSR phase are abolished;

(3) Modulation of ASSR and N1 Amplitude by attention is abolished or impaired;

(4) But P2 amplitude increases normally with training in Tinnitus

11 tinnitus subjects

11 control subjects

Age and hearing level matched

Trained for 7 sessions to detect

targets in a 5 kHz 40-Hz AM

sound in the TFR of the tinnitus

subjects

Alternating active/passive blocks

Roberts, Bosnyak, & Thompson (2012)

Front. Syst. Neurosci. 6:40. doi: 10.3389/fnsys.2012.00040

ASSR Phase:

ASSR

N1

ASSR and N1 amplitude:

p = 0.022 2-way

p = 0.016 3-way

p = 0.05

p = 0.03

tinnitus

controls

ASSR

N1

Day 1

Probe

5 kHz

Attention Effects

(active minus passive blocks)

tinnitus

controls

Probe

5 kHz

ASSR

N1

Day 1

Probe

500 Hz

Attention Effects

(active minus passive blocks)

Tinnitus: baseline

PFC Attention

System

Tinnitus: detect 5 kHz target

Task Requirement (detect 5 kHz targets)

PFC Attention

System

Tinnitus: detect 500 Hz target

Task Requirement (detect 500 Hz targets)

Rules of Plasticity and Attention in tinnitus: (1) Cortical representations can grow in TFR of A1 for trained sounds; (2) Cortical representations in A2 remain plastic (maybe more so);

(3) Temporal changes normally expressed in A1 are obstructed, more so if

the training sound nears the peak of the tinnitus spectrum; (3) Top-down auditory attention works normally in tinnitus, but modulation

of tinnitus-related neural activity in A1 and A2 is obstructed;

(4) These effects are consistent with the neural changes seen in tinnitus accompanied by hearing loss:

(decreased inhibition and increased spontaneous/synchronous neural activity in the hearing loss regions of auditory cortex)

Three Topics:

(1) Neural Plasticity in normal hearing

(2) Are the rules changed in tinnitus ?

(3) Sound therapy for tinnitus

Does Sound Therapy Work for Tinnitus?

Active training within the TFR

Active training outside the TFR

Passive experience within the TFR

Passive experience outside the TFR

Does Sound Therapy Work for Tinnitus?

Flor, Hoffmann, Struve, Diesch (2004) Appl. Psychophysiol. Biofeedback 29(2):113-20.

Herriaz, Diges, Cobo, Plaza, Aparicio (2006) Acta Oto-Laryngologica 126:8083.

Herriaz, Diges, Cobo, Aparicio (2009) Eur. Arch Otorhinolaryngol. 266:9–16

Noreña, Micheyl, Chéry-Croze, Collet (2002) Audiol. Neurootol. 7:358-69.

Searchfield, Morrison-Low, Wise (2007) Prog. Brain Res. 166:369-75.

Baguley, Atlas (2007) Prog. Brain Res. 166:369-75.

Folmer, Carroll (2006) Otolaryng. Head Neck Surg. 134:132–137.

Moffat, Adjout, Gallego, Thai-Van, Collet, A Norena (2009) Hearing Res. 254:82-91.

Davis, Paki, Hanley (2007) Ear & Hearing 28(2):242-259.

Davis, Wilde, Steed, Hanley (2008) Ear, Nose and Throat Journal 87:330-339.

Hanley, Davis, Paki, Quinn, Bellekom (2008) Ann. Otol. Rhinol. Laryngol. 117:791-799.

Folmer, Carroll (2006) Otolaryng. Head Neck Surg. 134:132–137.

Henry, Schechter, Zaugg et al (2006) J. Am. Acad. Audiol. 17:104-132.

Okamoto, Stracke, Stoll, Pantev (2010) Proceed. Nat. Acad. Sci. USA

Tiesman, Okamoto, and Pantev PLoS One (2011) .

Tass et al. Restorative Neurology and Neuroscience 30 (2012) 137–159

Roberts and Bosnyak (2010). In A. Moller, et al..(Eds) Textbook of

Tinnitus Humana Springer Press]

(Updated)

These results are disappointing

7 best results (all

subjects):

VAS - 20.4%

Monitoring alone:

-12.0%

Effect of Sound

Therapy:

- 8.4%

16 studies overall

Does sound matter at all?

Here are some reasons why it should

Normal hearing cat exposed to 4-20 kHz

tone pip ensemble 68 dB SPL 6 to 8 weeks

12h/day 24h/day

1-3 weeks

8-12 weeks

Pienkowski M, Eggermont JJ.

Ear Hear. 2012 May-Jun;33(3):305-14.

Lo

ca

l fie

ld p

ote

ntia

ls

control

exposed

control

exposed

Recovery

Cats sleep a lot

control

exposed

Formby , Sherlock, & Gold

(2003)

J. Acoust. Soc. Am.

114:55–58.

Noreña & Eggermont, 2005.

J. Neurosci. 25, 699–705.

EAE 6-20 kHz

23h/day 2

weeks

High frequency ABR

thresholds recovered

in these animals

Loudness Growth

Map Reorganization

(1) Loss of inhibition means that neural representations can

increase in Tinnitus Frequency Region;

(2) Increased and persistent activity in attention networks;

(3) Tinnitus-related neural changes consequent on

deafferentation may impede therapeutic remodeling by

sound exposure;

(Training with a pure tone in the TFR is not a good idea)

Is Cochlear damage a game-changer?

Roberts, Moffat, Baumann, Ward, and Bosnyak (2008) J. Res. Otolaryngology (JARO) 9:417-435.

Schaette & McApline

Gu & Melcher

Hebert & Fournier

Kujawa & Liberman

Roberts, Moffat, Baumann, Ward, and Bosnyak (2008) J. Res. Otolaryngology (JARO) 9:417-435.

A To-Do List

(1) We need better measures of cochlear pathology than the audiogram

(2) Animal studies could tell us how suppression of neuron response

properties by sound is modulated by different levels of threshold shift:

(3) Is neural remodeling impaired outside of the TFR of tinnitus sufferers?

(4) Immersion in sound: sleep?

(5) Does early intervention with sound improve cochlear function?

(6) Hearing restoration technologies

(7) Invest in prevention of hearing loss

Dangerous Decibels (William Martin)

www.dangerousdecibels.org

Roberts, Martin, & Bosnyak (2010). The prevention of tinnitus and noise-induced hearing loss.

Textbook Of Tinnitus Eds: Møller et. Humana-Springer (pp 527-534)

Ground-Shaking Noise Rocks N.F.L., and Eardrums Take Big Hit

Arrowhead Stadium, Kansas City, October 13, 2013 World Record 137.6 dB A scale

November 16 2013 by Joyce Cohen

Ian Bruce Dan Bosnyak Brandon Paul

TINNITUS RESEARCH INITIATIVE

With thanks to:

Graeme Moffat V ictoria Mosher Taylor Tuff Dave Thompson

Antoine Shahin Laurel Trainor

Tinnitus Plasticity

Phil Gander Scott Baynton

The Neurological Foundation of New Zealand and the New Zealand Tinnitus and Hyperacusis Network