The purpose of this study was to assess the reliability and validity of a new computerized method of assessing balance and gaze control under a broad range of physical and visual conditions in people with vestibular hypofunction. Test retest reliability for balance performance as measured by COP excursion was good in all conditions with ICCs ranging from .64 to .90 in the AP and ML directions. Closed loop visual tracking as measured by COD had high reliability on the sponge and treadmill (ICC=.71-.75) as compared to open loop tracking (ICC=.325-.463) which was poor. Convergent validity showed poor correlation between clinical tests and the electronic balance and gaze assessments. Construct validity demonstrated that as physical and visual loads increased, balance performance decreased significantly on the sponge as measured by an increase in COP excursion and visual tracking performance decreased significantly on the treadmill as measured by a decrease in COD.

The purpose of this study was to assess the reliability and validity of a new computerized method of assessing balance and gaze control under a broad range of physical and visual conditions in people with vestibular hypofunction. Test retest reliability for balance performance as measured by COP excursion was good in all conditions with ICCs ranging from .64 to .90 in the AP and ML directions. Closed loop visual tracking as measured by COD had high reliability on the sponge and treadmill (ICC=.71-.75) as compared to open loop tracking (ICC=.325-.463) which was poor. Convergent validity showed poor correlation between clinical tests and the electronic balance and gaze assessments. Construct validity demonstrated that as physical and visual loads increased, balance performance decreased significantly on the sponge as measured by an increase in COP excursion and visual tracking performance decreased significantly on the treadmill as measured by a decrease in COD.

Some patients suffer hearing loss in the early postoperative period following vestibular schwannoma (VS) excision despite having intact hearing immediately after surgery. As this phenomenon has rarely been documented or described, the putative mechanism remains vague. The objective of the current study was to document the patterns of change in behavioural and electrophysiological responses in patients following VS surgery to better describe the phenomenon of delayed hearing loss. In particular, we aimed to determine whether the impairment that eventually leads to delayed hearing loss is neural or cochlear in origin. Auditory function was monitored in six adult patients who underwent surgery at Christchurch Public Hospital for excision of unilateral vestibular schwannoma through the retrosigmoid approach. Patients were assessed pre- and postoperatively by puretone audiometry, speech audiometry, tympanometry, distortion product otoacoustic emissions (DPOAEs), and auditory brainstem response (ABR). When measurable hearing was demonstrated postoperatively, pure-tone audiometry, speech audiometry and ABR were assessed at 24 hour intervals following surgery. Transtympanic electrocochleography (ECochG) was carried out if wave I of the ABR was lost during the postoperative period. Postoperative monitoring revealed that 4 patients suffered permanent anacusis and the remaining 2 patients had permanent hearing preservation. There were no patients who experienced delayed hearing loss in the early postoperative period. A phenomenon similar to delayed hearing loss was observed in case 2 who demonstrated loss of ABR wave I on the 7th postoperative day. Postoperative ECochG recorded in this case showed an enhanced negative SP on the operated side. The findings of this study are discussed in detail with particular reference to the underlying pathophysiology.

Thesis (M. Sc. Med.)--Discipline of Medicine, Faculty of Medicine, University of Sydney, 2007. / Title from title screen (viewed June 20, 2007). Submitted in fulfilment of the requirements for the degree of Master of Science in Medicine to the Faculty of Medicine. Degree awarded 2007; thesis submitted 2005. Includes bibliography. Also issued in print.

Thesis (M. Phil.)--University of Hong Kong, 2007. / Also available in print.

Thesis (M.S.)--Florida State University, 2004. / Advisor: Dr. Richard Hyson, Florida State University, College of Arts and Sciences, Dept. of Psychology. Title and description from dissertation home page (viewed Jan. 19, 2005). Includes bibliographical references.

Thesis (Ph. D.)--University of Hong Kong, 1999. / Includes bibliographical references (leaves 181-203).

Thesis (Ph.D.)--University of Hong Kong, 1999. / Includes bibliographical references (leaves 181-203) Also available in print.

Thesis (doctoral)--Rijksuniversiteit te Groningen.

Thesis (Ph. D.)--University of Hong Kong, 2005. / Title proper from title frame. Also available in printed format.