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J P Martens

Publications and source records attributed to J P Martens.

7 recordsLinked to original sources
PubMed2005

Perceptual evaluation of substitution voices: development and evaluation of the (I)INFVo rating scale.

Substitution voicing cannot be evaluated accurately by the GRBAS perceptual rating scale, and there is a need for a valuable alternative. Therefore, we developed and tried out a perceptual rating scale, consisting of five new parameters: impression, intelligibility, noise, fluency and voicing, each to be scored between 0 (very bad score) to 10 (very good score for a substitution voice). In analogy to the GRBAS scale, they are then converted to deviance scores ranging from 0 (similar to good substitution voicing) to 3 (very deviant from good substitution voicing). Inter-individual agreement measured in a set of 24 semi-professional jury members seemed to be moderate for all parameters. Mean figures of 0.52, 0.51, 0.46, 0.53 and 0.46 are obtained for the parameters impression, intelligibility, noise, fluency and voicing, respectively. Because a high correlation exists between the first two parameters (0.917) and relying on the correlation figures between the two "I"s and the other parameters (correlation values for "impression" vary from 0.79-0.86; values for "intelligibility" range from 0.74-0.83), we suggest to discard the parameter impression, which turns the actual IINFVo scale into INFVo. The proposed (I)INFVo perceptual rating scale seems promising for the assessment of substitution voicing. Eventual improvements and practical proposals are discussed.

Humans↗
PubMed2005

[Perceptive evaluation of substitution voices: the I(I) NFVo rating scale].

OBJECTIVES: Evaluation of a perceptual specific rating scale for specific severe non laryngeral dysphonia. MATERIAL AND METHOD: 113 speech samples from substitution voices were scored perceptually according to the IINFVo scale: overall quality impression (I), impression of Intelligibility (I), additive and unnecessary noise (N), speech fluency (F) and presence of voiced segments (Vo). Each parameter was scored on a visual analogue scale from 0 (minimally deviant) to 10 (maximally deviant substitution voicing). These samples were presented to semi-professional jury-members (second grade speech therapy students) and professional jury-members (phoniatricians and speech therapists, specialised in the oncological field). RESULTS: Interindividual agreement between semi-professionals was moderate (0.57-0.68). Interindividual agreement between professionals was higher (0.82-0.86). These figures are similar or even better compared to the classical perceptual evaluation scale for laryngeal speech (GRBAS). CONCLUSION: Our study suggests that the I(I)NFVo rating scale is suitable for perceptual evaluation of substitution voicing and consistency results are comparable with the classical perceptual rating scale (GRBAS).

Humans↗
PubMed2003

Detection of spike and wave discharges in the cortical EEG of genetic absence epilepsy rats from Strasbourg.

Genetic absence epilepsy rats from Strasbourg (GAERS) are a strain of Wistar rats in which all animals present spontaneous occurrence of spike and wave discharges (SWD) in the cortical electroencephalogram (EEG). In this paper, we present a method for the detection of SWD, based on the key observation that SWD are quasi-periodic signals. A spectral-comb based analysis method is used to extract the fundamental frequency and the percentage of energy explained by the harmonic spectral components is subsequently used as a detection parameter. It is shown that a maximum sensitivity and specificity of up to 96 per cent can be achieved. We also compared the performance of this method with the methods presented in the literature and conclude that the surplus value of the novel detection method lies in the higher specificity that can be obtained in the analysis of long-term EEG fragments, which are contaminated by artefacts and contain large portions of slow-wave sleep.

Action Potentials↗
PubMed1992

Pitch and voiced/unvoiced determination with an auditory model.

In this paper, an accurate pitch and voiced/unvoiced determination algorithm for speech analysis is described. The algorithm is called AMPEX (auditory model-based pitch extractor) and it performs a temporal analysis of the outputs emerging from a new auditory model. However, in spite of its use of an auditory model, AMPEX should not be regarded as a substitute for any psychophysical theory of human auditory pitch perception. What is mainly described is the design of a computationally efficient auditory model, the perceptually motivated determination of the model parameters, the conception of a reliable pitch extractor for speech analysis, and the elaboration of an experimental procedure for evaluating the performance of such a pitch extractor. In the course of the evaluation experiment several kinds of speech stimuli including clean speech, bandpass-filtered speech, and noisy speech were presented to three different pitch extractors. The experimental results clearly indicate that AMPEX outperforms the best algorithms available.

Auditory Threshold↗
PubMed1984

Conducting nonadaptive psychoacoustic or biomedical tests by means of an interactive program.

The program described in this paper was originally designed to generate the (synthetic) stimuli required for a large class of psychoacoustic tests. In our opinion, however, it may also be of interest in other fields of biomedical information processing. The applied computational techniques are standard in the field of digital signal processing, but the program is particular in its way of presenting signals, executing window operations, and describing the decision blocks to be presented during a test. Each decision block is a succession of stimuli and pauses, presented to obtain one judgement from the subject.

Computers↗
PubMed1982

A new theory for multitone masking.

In order to explain masked thresholds of a tonal probe centered between two tone maskers, Green [J. Acoust. Soc. Am. 37, 802-813 (1965)] introduced his famous energy-detection model. We argue that the model is in some respects inadequate and inconsistent with measurements of roughness, at least one psychological correlate of temporal fluctuations. Furthermore, it requires the assumption that tones interact over frequency distances considerably beyond a critical bandwidth. Therefore we propose an alternative theory that allows reconciliation of Green's measurements with the commonly accepted critical-band hypothesis. Our model is based on the hypothesis that the auditory system is capable of performing a spectral analysis of the time pattern of the waveform envelope. Important effects of probe type (noise, tone, or complex) and phase between masker and probe seem easily explained by the model. Also, the differences between two- and four-tone masking are successfully predicted. Finally, as a byproduct, our theory offers and explanation for the just noticeable amplitude modulation (AM) and frequency modulation (FM) of a sinusoidal carrier.

Humans↗