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Effects of hearing loss and hearing aids on quality of life and cognitive decline. Harvey Dillon, Gitte Keidser National Acoustic Laboratories and The Hearing Cooperative Research Centre Better Hearing National Conference 2013. Impact of untreated hearing loss on health.
Effects of hearing loss and hearing aids on quality of life and cognitive decline Harvey Dillon, GitteKeidser National Acoustic Laboratories and The Hearing Cooperative Research Centre Better Hearing National Conference 2013
Impact of untreated hearing loss on health • Proven links between hearing loss and: • depression / mood / emotional state • social isolation, loneliness, withdrawal • self-sufficiency • cognitive ability • physical and psychological well-being • life expectancy • Asserted links between hearing loss and: • anxiety • paranoia • exhaustion • insecurity • loss of group affiliation • loss of intimacy • anger / irritation • distress / fear • embarrassment • unemployment • restricted travel
Cardio-vascular disease Activity restriction Effects of hearing loss? Hearing loss Mortality Depression We just can’t deduce causation from these surveys of health
Mortality Depression Isolation Anxiety Insecurity etc Effects of hearing aids? Hearing loss
Hearing loss Better: Mood / less depression Emotional state Self-sufficiency Social relationships Life expectancy Less isolation. More able to deal with problems Cross-sectional studies Hearing loss and hearing aids
Fatalistic people (external locus of control) Hearing loss Better: Mood / less depression Emotional state Self-sufficiency Social relationships Life expectancy Pro-active people (internal locus of control) Cross-sectional studies Hearing loss and hearing aids
Attend to major sickness Hearing loss Attend to hearing loss Better: Mood / less depression Emotional state Self-sufficiency Social relationships Life expectancy Cross-sectional studies Unwell people, with hearing loss Healthy people, with hearing loss Hearing loss and hearing aids
Better: Social relationships Cognitive functioning Memory Learning ability Less depression Less paranoia + Hearing loss Longitudinal studies Mulrow et al (1990); Dye & Peak (1983)
Longitudinal study:Lin et al (2013) Johns Hopkins Centre, USA Sample • 1,984 adults, mean age =77 years, no dementia • 58% had hearing loss (>25 dB 4FA in better ear) • Cognitive ability measured 6 years later Results • Those with hearing loss had rate of cognitive decline 37% greater than those with no loss • Rate of decline increased significantly with hearing loss • Rate of decline much less for those with hearing aids, but difference not statistically significant & not randomised • Adjusted for age, sex, race, education, smoking status, hypertension, diabetes mellitus, stroke history • Cause and effect likely but not proven
Rate of cognitive decline per year Effect of hearing loss on cognitive decline
Rate of cognitive decline per year * * Beneficial effect of hearing aids
Effects of hearing loss Isolation Poor Working memory Hearing loss Cognitive decline, dementia Poor speech understanding Something else
UK Biobank • Extensive data on over 100,000 people • Aged 40 to 69 years • Relation of hearing loss to other factors being analysed by Dr Keidser at NAL • Attempting to investigate path from hearing loss to depression and cognitive abilities by statistical methods
UK Biobank data No hearing loss Hearing loss
Why do people hear but not understand? ….. and what NAL is doing about it
Noise damaged Good
The hair cells can die (noise, drugs, age) What can go wrong?
Vowel spectra and audibility oo Sound level First formant Second formant ee 250 500 1000 2000 4000 Frequency (Hz)
Reduced dynamic range with hearing loss Too loud Intense Moderate Weak Too soft (a) Norm Too loud Too loud Intense Intense Moderate Moderate Weak Weak Too soft Too soft (b) (c) Sam
Prescribing hearing aids to maximise intelligibility and control loudness NAL-NL2 (2011) NAL-NL1 (1999) NAL-RP (1991) NAL-R (1986) NAL (1976)
250 1000 4000 250 1000 4000 Frequency resolution in hearing loss (a) Sound level (b) Excitation Frequency (Hz)
Super-directional microphones Front NAL binaural beamformer + + Right Right Beamformer and DOA HRTF Delay DOA + Left Left + To CAPD Mejia To end
Outcomes of children with hearing impairment Teresa YC Ching, and team
Outcomes T Ching, NAL, HEARing CRC
At 5 years, early CI linked to better outcomes (n = 104) Implant age: p = 0.0006 T Ching, NAL, HEARing CRC
So baby, how does it sound? Objective hearing aid evaluation for: • young infants • difficult-to-test people
Parietal lobe Frontal lobe Occipital lobe Temporal lobe Sylvian fissure Superior temporal gyrus Hearing disorders in the brain
Spatial Processing Disorder Speech Lack of spatial release from masking Noise Noise Noise Noise Cameron, Dillon & Newall
LISN & Learn Game Target at 0˚: Distracters at + and -90˚:
LiSN & Learn - Performance Over Time (n=9) 10 dB Better LiSN & Learn SRT (dB) Cameron & Dillon (2011)
Randomized Control Trial Cameron, Glyde & Dillon (2012) Earobics Lisn & Learn N = 5 N = 5
Future researchCentral processing disorders in elderly people • Blue Mountains Study: Golding et al (2004) • Studied 1576 people > 55 years • Battery of 7 tests • 76% failed 1 or more tests • 64% failed 2 or more tests • But can we give training to overcome it?
Thanks for listening www.NAL.gov.au Volunteers needed ! NAL is funded by the Federal Department of Health, Office of Hearing Services.