Auditory impairment in patients with craniofacial clefts has been well studied for
decades. However, most previous research has only focused on middle ear disorders
and related auditory consequences in this group. Studies of higher level auditory
status and central auditory processing abilities of this group—particularly in
children—have been unsystematic and have significant limitations, while the
potentially negative impact of central auditory impairment on children should not be
ignored. One important area which needs further research is the status of the central
auditory nervous system (CANS) in children with non-syndromic cleft lip and/or palate (NSCLP). In order to objectively investigate possible central auditory
impairment in children with NSCLP, the present research programme was initiated.
Firstly, two major studies aimed to provide anatomical structural analysis and
functional evaluation of the auditory structures of CANS in a group of infants with
NSCLP, and compare the results to those of normal controls (Studies 1 and 2).
Secondly, a pilot study (Study 3) was conducted to provide preliminary data and
suggest methodology to support a major, future research programme to
comprehensively investigate central auditory processing abilities in children with
NSCLP.
A multi-disciplinary approach that included brain magnetic resonance image
(MRI) scanning, auditory evoked potentials (AEP) recording, and a central
behavioural auditory test battery assessment protocol, was applied in the present
research programme. Based on the results of the studies and data analysis, it was
concluded that: (1) Structural abnormalities of CANS in infants with NSCLP may be
primarily located in the left cerebral hemisphere and cortical abnormalities were more
marked compared with those in other subcortical locations. The development and
maturation of the auditory cortex in infants with NSCLP may be abnormal, compared
with that in normal children; (2) Infants with NSCLP might have normal auditory
sensory function at brain stem and subcortical levels, yet this group may have
significant impaired auditory discriminatory function at cortical level; (3) Children with NSCLP may show normal auditory processing abilities in a quiet listening
environment. However, they may be more vulnerable to background noise and have
impaired auditory processing abilities in areas such as monaural low redundancy and
temporal resolution ability.
In summary, combining the results of MRI, AEP and behavioural measurements
in the present research programme, it is suggested that children with NSCLP are at
potential risk of both structural abnormalities and functional disorders of the CANS,
particularly at auditory cortical level. In addition, this group might also be at risk of
auditory processing impairments to some degree, particularly in noisy environments.
The present research programme has made a contribution to our understanding of the
central auditory status of children with NSCLP, which was not systematically
investigated in previous studies, and provided information on which to base further
research. The research findings should draw the attention of researchers and clinicians
to improving auditory assessment and intervention for patients with craniofacial cleft
disorders. Further efforts in this field in the long-term may help to develop a more
sophisticated audiological evaluation and intervention approach for this population. / published_or_final_version / Speech and Hearing Sciences / Doctoral / Doctor of Philosophy
| Identifer | oai:union.ndltd.org:HKU/oai:hub.hku.hk:10722/146130 |
| Date | January 2011 |
| Creators | Yang, Feng, Frank., 杨峰. |
| Contributors | McPherson, DB |
| Publisher | The University of Hong Kong (Pokfulam, Hong Kong) |
| Source Sets | Hong Kong University Theses |
| Language | English |
| Detected Language | English |
| Type | PG_Thesis |
| Source | http://hub.hku.hk/bib/B47231841 |
| Rights | The author retains all proprietary rights, (such as patent rights) and the right to use in future works., Creative Commons: Attribution 3.0 Hong Kong License |
| Relation | HKU Theses Online (HKUTO) |
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