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Wayne J Wilson

Publications and source records attributed to Wayne J Wilson.

7 recordsLinked to original sources
PubMed2006

Over-complete discrete wavelet transformation of the normal auditory brainstem response improves prediction of outcome following severe acute closed head injury.

Previous research has shown that complex statistical analysis (discriminant function analysis) of a 'normal' auditory brainstem response (ABR) result can improve this measure's ability to predict subject outcome following severe acute closed head injury (ACHI). We hypothesized that adding the ABR's time-frequency information to such an analysis would improve this predictive value even further. 'Normal' ABR results were sampled from 69 severe ACHI subjects (22 of whom died and 47 of whom lived) and their time-frequency information extracted using an over-complete discrete wavelet transformation (OCDWT). A series of logistic regression analyses then showed correct predictions of death and survival as follows: ABR measures only 72 and 89% (respectively), ABR OCDWT measures only 82 and 89% (respectively), and ABR and ABR OCDWT measures combined 86 and 93% (respectively). These results showed that the addition of time-frequency information can improve the ability of the 'normal' ABR result to predict outcome following severe ACHI.

Acoustic Stimulation↗
PubMed2004

Automated analysis of the auditory brainstem response using derivative estimation wavelets.

In this paper, we describe an algorithm that automatically detects and labels peaks I-VII of the normal, suprathreshold auditory brainstem response (ABR). The algorithm proceeds in three stages, with the option of a fourth: (1) all candidate peaks and troughs in the ABR waveform are identified using zero crossings of the first derivative, (2) peaks I-VII are identified from these candidate peaks based on their latency and morphology, (3) if required, peaks II and IV are identified as points of inflection using zero crossings of the second derivative and (4) interpeak troughs are identified before peak latencies and amplitudes are measured. The performance of the algorithm was estimated on a set of 240 normal ABR waveforms recorded using a stimulus intensity of 90 dBnHL. When compared to an expert audiologist, the algorithm correctly identified the major ABR peaks (I, III and V) in 96-98% of the waveforms and the minor ABR peaks (II, IV, VI and VII) in 45-83% of waveforms. Whilst peak II was correctly identified in only 83% and peak IV in 77% of waveforms, it was shown that 5% of the peak II identifications and 31% of the peak IV identifications came as a direct result of allowing these peaks to be found as points of inflection.

Adolescent↗
PubMed2003

The performance of South African English first language child speakers on a "low linguistically loaded" central auditory processing test protocol.

The lack of standardized tests for central auditory processing disorders (CAPD) in South Africa (SA) led to the formation of a SA CAPD Taskforce, and the interim development of a "Low Linguistically Loaded" CAPD test protocol using test recordings from the 'Tonal and Speech Materials for Auditory Perceptual Assessment Disc 2.0'. This study compared the performance of 50 SA English first language child speakers (aged 8 to 12 years of age) on this protocol, with the previously published American normative data of Bellis (1996, 2003). Results with respect to predicted pass criteria as calculated by mean-2SD cutoffs, suggested that the SA speakers performed of a lower level than the American speakers by an average of 5.3% per ear for the two pair dichotic digits test, 1.9 dB for the masking level difference test, 8.8% per ear for the frequency pattern test--humming report, 14.5% per ear for the frequency patterns test--verbal report, and 39.7% per ear for the low pass filtered speech test. Consequently, the Bellis (1996, 2003) data was not considered appropriate for immediate use as normative data in SA. Instead, the preliminary data provided in this study was recommended as interim normative data for SA English first language child speakers until larger scale SA normative data can be obtained.

Audiometry, Speech↗
PubMed2003

The performance of South African English first and second adult speakers on a "low linguistically loaded" central auditory processing test protocol.

The lack of standardized tests of central auditory processing disorder (CAPD) in South Africa (SA) led to the formation of a SA CAPD Taskforce, and the interim development of a "low linguistically loaded" CAPD test protocol using test recordings from the 'Tonal and Speech Materials for Auditory Perceptual Assessment Disc 2.0'. This study inferentially compared the performance of 16 SA English first, and 16 SA English second, language adult speakers on this test protocol, and descriptively compared their performances to previously published American normative data. Comparisons between the SA English first and second language speakers showed a poorer right ear performance (p < .05) by the second language speakers on the two-pair dichotic digits test only. Equivalent performances (p < .05) were observed on the left ear performance on the two pair dichotic digits test, and the frequency patterns test, the duration patterns test, the low-pass filtered speech test, the 45% time compressed speech test, the speech masking level difference test, and the consonant vowel consonant (CVC) binaural fusion test. Comparisons between the SA English and the American normative data showed many large differences (up to 37.1% with respect to predicted pass criteria as calculated by mean-2SD cutoffs), with the SA English speakers performing both better and worse depending on the test involved. As a result, the American normative data was not considered appropriate for immediate use as normative data in SA. Instead, the preliminary data provided in this study was recommended as interim normative data for both SA English first and second language adult speakers, until larger scale SA normative data can be obtained.

Adolescent↗
PubMed2002

The effects of high stimulus rate on the electrocochleogram in normal-hearing subjects.

The use of high stimulus rates has the potential to improve the electrocochleogram's (ECochG) sensitivity and specificity in endolymphatic hydrops and Menière's disease, but is currently hindered by the absence of an acceptable normative database. In response, this study recorded click-evoked ECochG tracings from 51 normal-hearing subjects (102 ears), between 18 and 60 years of age, at 7.1, 51.1, 101.1 and 151.1 clicks/s using a tympanic membrane electrode. As stimulus rate increased, various statistically significant (p < 0.05) changes were observed. In general, summating potential (SP) latency and amplitude and action potential (AP) latency increased, SP/AP amplitude ratio and waveform width increased but then plateaued, and AP amplitude fluctuated. While providing the largest contribution to a high-stimulus-rate ECochG normative database published to date, potential clinical limitations were identified and a possible solution proposed.

Acoustic Stimulation↗
PubMed2002

Improving the prediction of outcome in severe acute closed head injury by using discriminant function analysis of normal auditory brainstem response latencies and amplitudes.

OBJECT: The auditory brainstem response (ABR) is a useful addition to standard medical measures for predicting outcome in patients with severe acute closed head injury (ACHI). Limiting this success, however, is the poor predictive value of a so-called "normal" ABR. In this study the authors used discriminant function analysis (DFA) of ABR Wave I, III, and V latencies and amplitudes to improve the predictive accuracy of the normal ABR, both as a single measure and in combination with other standard medical measures. METHODS: The DFAs were conducted using the ABR and medical results in 68 patients with severe ACHI (30 who died [ACHI-died], and 38 who survived [ACHI-lived]) who presented with normal ABR responses in the neurosurgical intensive care unit of the authors' hospital in Johannesburg. All patients had undergone surgery to remove an intracranial hematoma. Correct predictions of outcome by ABR DFA measures were 83% for the ACHI-died group (48% at > or = 90% confidence level) and 87% for the ACHI-lived group (71% at > or = 90% confidence level); by medical DFA measures the correct predictions were 83% for the ACHI-died group (96% at >; or = 90% confidence level) and 95% for the ACHI-lived group (94% at > or = 90% confidence level); and by combined ABR and medical DFA measures correct predictions were 100% for the ACHI-died group (100% at > or = 90% confidence level) and 97% for the ACHI-lived group (100% at > or = 90% confidence level). CONCLUSIONS: The DFA of ABR Wave I, III, and V latencies and amplitudes improved the predictive ability of normal ABR results to rates similar to those obtained using DFA for the medical measures, although at lower confidence levels. The DFA of the combined ABR and medical measures improved correct predictions to rates significantly higher than for either of the measures on its own.

Acute Disease↗