Children with Mild and Unilateral Hearing Impairment Current management and outcome measures Kirsti Reeve Ph.D. Developmental Disabilities Institute Wayne State University, Detroit MI EDHI Feb 2004

Overview Current management for children with mild and unilateral hearing impairment (HI) Outcome measures: Speech and language Cognition

Why these populations? Very little known about management or outcomes for mild or unilateral HI NHSP offers the potential for early identification There is strong evidence that early identification gives improved outcomes in moderate and greater HI populations Need to ascertain whether it would be appropriate for these groups

Study overview Two separate studies Questionnaire survey to audiologists investigating management options Outcomes study Obtained epidemiological data Assessed impact of HI quality of life Assessed impact of HI on speech, language & cognition

Current management: options for children with mild or unilateral hearing impairment

Why assess service provision? Areas of uncertainty Numbers of children being identified Age of identification Management options for these groups Level at which to provide hearing aids

How was it done? Single page questionnaire survey Sent out to 131 professionals throughout the UK 1 reminder 56 responses (43%)

Results Information on the mild and unilateral cases seen Management offered to those cases

Results Information on the mild and unilateral cases seen Management offered to those cases

Numbers of children with bilateral mild impairment Defined as 20-40dBHL permanent sensorineural loss Comprise 8% of total caseload Range seen from 0 to 300 (mean of 25) Estimated total number seen by 56 clinicians: 1220

Numbers of children with unilateral hearing impairment Defined as permanent sensorineural loss in one ear only. Comprise 4% of total caseload Range seen from 0 to 40 (mean of 9) Estimated total number seen by 56 clinicians: 443

Numbers of children seen

Numbers found Literature estimates prevalence figures at: between % for unilateral impairment Between 1 and 5.4% for mild impairment It is well recognized that an inverse relationship exists between the prevalence and degree of hearing loss – Bess 1984 The low percentage as ascertained by this questionnaire would imply that large numbers of these populations are not receiving audiological management

Age of Referral

Age of referral, data from Trent Region (Mild n=50, Unilateral = 30) percentiles Age in months X, X X X X X,,, ' ) Moderate All Trent Mild Unilateral X

Age of referral Age of referral is late for both groups of children when compared with Trent data Children with unilateral impairment identified significantly later than children with mild impairment Modal age of between 4 and 6 years suggests that the school entry is a factor leading to identification

Results Information on the mild and unilateral cases seen Management offered to those cases

Management

Most frequent options are review and advice Children with mild HI are significantly more likely to be offered: Hearing Aids (p=0.0005) Speech Therapy (p=0.003) Referral to other professional (p=0.022)

Provision of aids Uncertainty among professionals on whether to aid mild HI Level below which you would not consider providing aids: 25dBHL (range from dBHL) Level above which you would definitely provide aids: 40dBHL (range from 25 to 50dbHL)

Management conclusions Mild and unilateral HI are under- represented in the caseload of this sample These groups of children are identified later than children with more severe impairments Management is still uncertain whether to provide aids and at what level for children with a bilateral mild impairment

Outcome Measures – Language and Cognition

Hypotheses Language is likely to be affected to some degree by a mild or unilateral hearing impairment There will be a positive relationship between language scores, non-word repetition and verbal reasoning

Subjects 41 children from CHAC met study criteria: Aged 6-11 Bilateral mild, or unilateral hearing impairment HI is sensorineural No associated syndromes, or other problems. No known learning or cognitive disabilities. English as first language 20 children agreed to participate though one child DNAd twice, and was not followed up a third time.

Participants 8 mild 11 unilateral 6 mild, 3 moderate, 1 severe, 1 profound 5 left ear impaired, 6 right ear 5 girls, 14 boys Aged 6-11, average age 8yrs 3 months Age of identification ranged from 9 months to 6 years 7 months (mean of 2 years 4 months)

Assessments The session consisted of: Computer based test of sound lateralization Standardised language assessment (CELF-3 UK) Childrens test of Non word Repetition BAS verbal & non-verbal reasoning (IQ) Most sessions lasted mins including breaks.

Results Language Non-word repetition Cognition

Results Language Non-word repetition Cognition

Language testing - CELF 3 UK Standardised on UK population Six subtests: 3 for receptive language (understanding) Sentence Structure (aged 6-8) / Semantic Relationships (aged 9+) Concepts and Directions Word Classes 3 for expressive language (speaking) Word Structure (6-8) / Sentence Assembly (9+) Formulated Sentences Recalling Sentences

Means of all language scores Standardised Test: mean:100, sd:15 Receptive Language Mean: 89.65, sd Expressive Language Mean: 85.76, sd Total Language Mean: 86.29, sd 14.01

Total Language Scores for individual subjects Unilateral HIMild HI

Speech & language results 1 Unilateral group - total language score mean of Mild group - total language score mean of With a linear regression, the difference in scores just misses significance (.089) - this could be due to the small sample size.

Speech & language results 2 Converting scores to age equivalent gives an average language delays of: 6 months for children with a unilateral impairment 24 months for children with a mild impairment

Results Language Non-word repetition Cognition

Childrens Test of Non-word Repetition Assesses phonological memory, and is predicative of literacy development Administered via computer Scores converted to standard scores, with a mean of 100, sd of 10

CN-Rep Results 1 Both groups of children scored below 100 on this task Children with mild HI: mean= Children with unilateral HI: mean=95.55

CN-Rep results by type of hearing impairment

CN-Rep results 2 Significant correlation of.953 with the recalling sentence CELF subtest (p=0.005) controlling for age Scores can be compared with those from an OME group and hearing controls from BOS study

CN-Rep scores as a function of type of hearing impairment

Results Language Non-word repetition Cognition

Two tests from the British Abilities Scale (BAS) Similarities (verbal reasoning) Why do these things go together: milk, lemonade, coffee, cod, shark, pilchard Need to produce the superordinate Matrices (non verbal reasoning) Finish the pattern

Cognition results 1 Similarities (verbal reasoning) centile scores ranged from mean of 45.71, sd 20 Matrices (non verbal reasoning) centile scores ranged from mean of 77.82, sd of So - significantly impaired scores on verbal reasoning (p<.001 on independent samples t- test)

Cognition results 2 Only 3 children, all with mild HI, had higher verbal than non-verbal reasoning Mean difference of 32 centiles between verbal and non-verbal scores Significant difference in non-verbal score depending on type of HI Independent samples t test gives p=0.027

Cognition results

Cognition results 4 Correlation of.625 between verbal reasoning and CELF language scores (p=0.003) Results can be compared across severity range with outcomes data from larger studies

Reasoning scores as a function of type of hearing impairment

Outcome measures conclusions The caveat - These children were all identified through CHAC. Therefore they have made it to the attention of the audiology services There may be ascertainment bias which could effect the results and make generalisation more difficult

Outcome measures conclusions Laterality of impairment for the unilateral group was not predictive of performance Greater severity of impairment was correlated with better performance on language outcomes... … although numbers are very small

Outcome measures conclusions Children with mild or unilateral hearing HI who are known to audiology services could be at risk for developing language problems Children with a bilateral mild impairment are perhaps at greater risk than those with a unilateral impairment, regardless of severity

Overall conclusions Children with mild impairments are showing language deficits that may possibly be ameliorated through earlier identification There is a need for further research in the area of amplification provision for mild impairments

Overall conclusions Children with unilateral impairments showed a variable performance which was not correlated with severity of impairment or side of impairment There is the need for a larger study to investigate these findings further Early identification through NHSP is still recommended

Thanks to Adrian Davis and Sally Hind at MRC Institute of Hearing Research, Nottingham Paul Shaw and the staff at CHAC, Nottingham Helen Spencer & Jabulani Sithole for statistical assistance Medical Research Council for PhD funding

Reasoning scores as a function of type of hearing impairment

Why does the prevalence increase with age? Is it… new cases (i.e. acquired losses)? progressive nature of mild cases? late onset? persistent OME?