The fitting
of a cochlear implant necessarily comprises both audiophonological and surgical
aspects.
The
surgical side requires considerable otological microsurgery experience and a
good knowledge of all aspects of child hearing-impairment.
The
audiophonology team has an essential part to play in pre-implant assessment. (BIAP
Rec. CT 07-01 “Information on cochlear
implants for hearing-impaired children”, BIAP Rec. CT
25-02 “ Parental guidance for parents of deaf children expected to be
fitted or already fitted with a cochlear implant”).
The
indications for the fitting of a cochlear implant in children are in a state of
flux.
They
concern younger and younger children and also the possibility of bilateral
implants and hybrid implants working through both electric and acoustic
stimulation.
This
recommendation proposes to define the role of the audiophonology team
concerning the elements for prognosis, successive assessments and continuous
observation of the child throughout the implantation process.
The
audiophonology team, defined by BIAP CT 14-01 bis
“Audiophonological structures”, is composed of
ENT
doctors, phoniatricians, paediatricians, neurologists, …
Psychologists
Speech
therapists
Audiologists,
hearing-aid audiologists or bio-engineers
Social
workers
Specialised
teachers
Any other
specialist called on.
Their
conclusions must be compared and confronted.
If the
paediatric cochlear implantation team is distinct from that in charge of the
child, it is under an obligation to collaborate with the latter (BIAP rec. CT 25-02).
The
commission wishes to stress certain aspects of the medical assessment:
The necessary consultation with the family and
if possible with the child in order to determine:
-
the
expectations, motivation and level of information in the family (BIAP rec. CT 07-01)
-
the
family history and child’s case-history
-
the
child’s behaviour
-
The
alarm signals that first motivated a hearing examination
-
Care
already in place (hearing-aid, guidance, re-education, complementary
examinations).
to observe:
o the child’s behaviour
o reactions to noise, to the voice
o level of psycho-motor development
o communication with family-members
o means of communication and quality
of interactions
o voice quality.
The necessity of a complete ENT examination
-
The
hearing examination will be carried out through behavioural audiometry with the
oto-neurological explorations judged necessary : impedancemetry, acoustic
oto-emissions, auditory evoked potentials, auditory steady-state response,
calorimetric vestibular examination, promontory test,
electrocochleography, etc.
-
The
complete hearing assessment requires close collaboration with hearing-aid
audiologists and speech therapists.
-
Detection,
through any further tests necessary, of other possible related disabilities
(BIAP rec. CT 21”Multiple disabilities and hearing
impairments”): visual, motor, neurological, cognitive, etc. (BIAP rec. CT
07-01)
In the case of retro-cochlear impairment, also
called “central deafness” or “neuropathy”, the commission again draws attention
to:
o the difficulty of diagnosis in this
type of lesion.
o the problem of family expectations
as to any fitting of a cochlear implant (BIAP rec. CT 21-04 and CT
25-03 “Parental guidance in the case of hearing-impaired children with
multiple disabilities.”).
-
Medical
imagery is essential for pre-implantation assessment. Computerised tomography and magnetic resonance imagery can show:
o inner ear cavity anomalies
o cochleo-labyrinthine ossifications
(after meningitis, otospongiosis, traumatism, …)
o central nervous system anomalies.
The information must be confronted with the observations made by all the members of pluri-disciplinary cochlear implant team and the team caring for the child.
HEARING-AID ASSESSMENT
It is
essential to determine not only the liminary and supraliminary tonal auditory
threshold but also the possible use of sufficient residual hearing dynamic.
A vocal
audiometry test should be carried out if the child is old enough.
The hearing
assessment should be repeated over time.
After
checking that the hearing aids are working correctly and the settings have been
adjusted to the child’s degree of deafness, the prosthetic gain should be assessed
by the usual methods, depending on the child’s age.
We
recommend assessing the prosthetic gain after both fitting and
observation have been carried out under good conditions.
The ability
to distinguish sounds and words is far more important than the tonal
threshold. It is therefore always
functional hearing that should be assessed: ability to distinguish sounds
and/or signifying language units through hearing alone. This capacity is usually assessed by vocal
audiometry testing with lists of words or phrases deprived of context (open
list).
If residual
hearing with prosthesis is insufficient for understanding without lip-reading,
the fitting of a cochlear implant should be considered.
Detection
of functional hearing is essential in borderline cases:
-
certain
cases of 1st degree very severe hearing loss
-
certain
cases of severe hearing loss
-
progressive
hearing loss and certain cases of mixed hearing loss
The information must be confronted with the observations made by all the members of pluri-disciplinary cochlear implant team and the team caring for the child.
In the
context of cochlear implant, speech therapy assessment is complex. Its aim is to serve as a basis for setting
up a rehabilitation program and providing reference data for later assessments.
It is drawn
up from tests and observation tables proper to each different country. These must be adapted to the child’s age and
stage of development as well as to the anamnesis data. (BIAP rec. CT 24-01 “Language development in children aged 0
to 3 years” and CT 24-02 “Early detection of
language disorders in children.”).
This
assessment must include the following information on the child and family
members:
It
assesses:
-
functional
hearing: ability to deal with auditory information (detection, distinguishing,
identification, comprehension of words and phrases in different contexts)
-
means
of communication (BIAP rec. CT 17-01
“Communication”, CT 17-03 “Bilingualism in the up-bringing and education
of the hearing-impaired child”
-
interaction
quality (reciprocal attention, communication rules, imitation capacity,…)
-
voice
quality
-
language
comprehension and expression (vocabulary level, intelligibility of verbal
emissions, mastery of morpho-syntactic structures, …) (BIAP rec. CT 20-01, 20-02, 20-03, 20-04 “Language
and language assessment”).
It
assesses:
-
means
of communication used by parents
-
interaction
quality (reciprocal attention, communication rules, imitation capacity, …)
-
time
available.
The information must be confronted with the observations made by all the members of pluri-disciplinary cochlear implant team and the team caring for the child.
This assessment constitutes a basic reference
for later assessments as well as for guiding the family towards the appropriate
specialists.
It requires an interview with parents and an
individual meeting with the
child.
-
the
course of events leading to their contemplating a cochlear implant for the
child
-
how
well informed they are about the implant and their motivation for such a plan
of action
-
the
emotions aroused by the prospect of a surgical operation
-
how
their expectations relate to the child’s needs and potentialities and to the
limitations of the prosthesis
-
how
this plan of action fits in with the family’s normal functioning
-
integration
of the cochlear implant into a general plan of education.
comprises:
-
observation
in both free conditions and assessment conditions
-
conversation
with the child if possible;
should
determine the child’s:
-
relationship
with others, desire to communicate, capacity for adaptation, affective and
cognitive potential, motivation as to the advantage of a cochlear implant;
allows
detection and assessment of any related disabilities (BIAP rec. CT 21-01, 21-02, 21-03 “Multiple disabilities and hearing
impairments. Deafness with related disabilities”).
If the
assessment reveals a risk of psychological disturbances, the implant project
must be reconsidered.
The information must be confronted with the observations made by all the members of pluri-disciplinary cochlear implant team and the team caring for the child.
________________________________________________________________
Gran Canaria - MAY 2004