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Children with Mild and Unilateral Hearing Impairment
Current management and outcome measures
Kirsti Reeve Ph.D.Developmental Disabilities InstituteWayne State University, Detroit MI
EDHI Feb 2004
Overview
Current management for children with mild and unilateral hearing impairment (HI)
Outcome measures:Speech and languageCognition
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 studiesQuestionnaire survey to audiologists
investigating management optionsOutcomes 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 uncertaintyNumbers of children being identifiedAge of identificationManagement options for these groupsLevel 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
0
5
10
15
20
25
0 1-5 6-10 11-15 16-20 21-25 26-30 31-35 36+
Numbers
N
Mild
Unilateral
Numbers found Literature estimates prevalence figures at:
between 0.5-5.2% 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
0
5
10
15
20
25
30
35
0-6 months 6-12 months 1-3 years 4-6 years 6 years +
Age
N
Mild
Unilateral
Age of referral, data from Trent Region(Mild n=50, Unilateral = 30)
percentiles
Age in months
X
,
X
X
X
X
X
,
,
,
'
)
100
90
80
70
60
50
40
30
20
10
00 10 20 30 40 50 60 70 80 90 100 110 120 130 140
ModerateAll TrentMildUnilateral
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
0 10 20 30 40 50
Aid
Advice
Refer
Review
Speech Therapy
None/Discharge
Op
tio
ns
Frequency
Unilateral
Mild
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 15 - 35dBHL)
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 DNA’d 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 lateralizationStandardised language assessment (CELF-3 UK)Children’s test of Non word RepetitionBAS verbal & non-verbal reasoning (IQ)
Most sessions lasted 90-120 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
171717N =
Total language score
Expressive language
Receptive language s
95
% C
I
110
100
90
80
70
Means of all language scoresStandardised Test: mean:100, sd:15
Receptive LanguageMean: 89.65,
sd 13.18
Expressive LanguageMean: 85.76,
sd 13.51
Total LanguageMean: 86.29,
sd 14.01
Total Language Scores for individual subjects
type of hearing impairment
2.52.01.51.0.5
Tota
l lan
guag
e sc
ore
120
110
100
90
80
70
60
Unilateral HI Mild HI
Speech & language results 1
Unilateral group - total language score mean of 91.78
Mild group - total language score mean of 80.12
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
impairment24 months for children with a mild impairment
Results
Language
Non-word repetition
Cognition
Children’s 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= 87.75
Children with unilateral HI: mean=95.55
CN-Rep results by type of hearing impairment
811N =
type of hearing impairment
bilateralunilateral
95
% C
I CN
-Re
p S
tan
da
rdis
ed
sco
re110
100
90
80
70
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
110.7
105.2
95.6
87.8
70
75
80
85
90
95
100
105
110
115
None OME Unilateral Mild
type of hearing impairment
sta
nd
ard
sco
re
Results
Language
Non-word repetition
Cognition
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 17-84 mean of 45.71, sd 20
Matrices (non verbal reasoning)centile scores ranged from 29-99mean of 77.82, sd of 23.55
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
89 89N =
type of hearing impairment
bilateralunilateral
95
% C
I100
80
60
40
20
Similarities centile
matrices centile
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
0
10
20
30
40
50
60
70
t-sc
ore
Verbal
Reasoning scores as a function of type of hearing impairment
0
10
20
30
40
50
60
70
t-sc
ore
Verbal
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
0
10
20
30
40
50
60
70
t-sc
ore
Non Verbal
Reasoning scores as a function of type of hearing impairment
46
48
50
52
54
56
58
60
62
64
t-sc
ore
Non Verbal
Reasoning scores as a function of type of hearing impairment
0
10
20
30
40
50
60
70
NoneOM
EUnilateral
Mild
Moderate
Severe
Profound
t-sc
ore
Verbal
Non Verbal
Reasoning scores as a function of type of hearing impairment
0
10
20
30
40
50
60
70
NoneOM
EUnilateral
Mild
Moderate
Severe
Profound
t-sc
ore
Verbal
Non Verbal
Why does the prevalence increase with age? Is it…
new cases (i.e. acquired losses)?
progressive nature of mild cases?
late onset?
persistent OME?