Cepstral analysis of normal and pathological voice in Spanish adults. ģ.ĝelgado-Hernández J, León-Gómez NM, Izquierdo-Arteaga LM, Llanos-Fumero Y. A cepstral analysis of normal and pathologic voice qualities in Iranian adults: A comparative study. However, according to the relatively limited number of studies in this area, more studies are required to clarify the efficacy of cepstral measures in different voice pathologies.ġ.ěoone DR, McFarlane SC, Berg SLV, Zraick RI. Results: Recent studies support the efficiency of CPP and CPPS to diagnose dysphonia.Ĭonclusion: It is reasonable for the voice care teams to use CPP and CPPS in the patients’ initial assessment and track the effects of treatment. However, the interventional studies that consider CPP and CPPS as one of their adjunct variables and studies that investigated the relationship of the cepstral measure with other parameters were not included. The articles that investigated the power of Cepstral Peak Prominence (CPP) and its smoothed version (CPPS) to differentiate dysphonia versus normal voice have been included. The searched keywords included “cepstral peak prominence”, “smoothed cepstral peak prominence”, “instrumental acoustic analysis”, “acoustic”, and “diagnosis”. Materials and Methods: We reviewed the available research studies between 20 narratively in PubMed, Scopus, Google Scholar, and Science Direct databases. This review article evaluates the related studies in the cepstral areas to ascertain whether they are efficient in the diagnosis of dysphonia. In recent years, many studies have investigated the cepstral measures compared with the other former acoustic parameters. PowerCepstrogram: To Table (cepstral peak prominences).Introduction: The acoustic analysis is one of the well-known methods for voice evaluation.In the next picture the trend line is of exponential decay type and consequently the peak prominence value has changed a little bit. Note that the first four lines in the script are only necessary to generate a PowerCepstrum of a part of a vowel.Ĭreate KlattGrid from vowel: "a", 0.3, 125, 800, 80, 1200, 80, 2300, 100, 2800, 0.1, 1000 Next picture of a PowerCepstrum with its straight blue trend line and its corresponding peak prominence value was generated with the following script. To be compatible with the past, a standard least squares line fit can also be chosen but it is much less precise than the other two because a least squares fit is much more influenced by the peak cepstral values than the other two. The "Robust" method corresponds to the incomplete theil regression and is computationally faster but somewhat less precise. The default method, "Robust slow", corresponds to Theil's robust line fit. Or, we could use an exponential model in which the background cepstral amplitudes decay in a non-linear fashion.ĭefines how the line that models the cepstrum background is calculated. The slope of this line will generally be negative because the background amplitudes get weaker for higher quefrencies. We can model it with a straight line as was done in Hillenbrand et al. If you choose the "Least squares" fit method then it matters more.ĭefines how to model the cepstrum background. In our analysis this value is not so critical if we use the robust fitting procedure. (1994) article was chosen as 0.001 s in order to reduce the effect of very low quefrency data on the straight line fit. The lower value for this range in the Hillenbrand et al. The quefrency range for which the amplitudes (in dB) will be modelled by a straight line. A pitchCeiling of 300 Hz will correspond to a lower quefrency of 1/300≈0.0033 seconds.ĭetermines how the amplitude and position of a peak are determined. The lower quefrency is determined as 1 / pitchCeiling and this value is in general more critical than the value of the upper quefrency which equals 1 / pitchFloor. The CPP measure represents how far the cepstral peak emerges from the cepstrum background.ĭetermine the limits of the quefrency range where a peak is searched for. The CPP measure is the difference in amplitude between the cepstral peak and the corresponding value on the trend line that is directly below the peak (i.e., the predicted magnitude for the quefrency at the cepstral peak). Calculates the cepstral peak prominence measure (CPP) as defined by Hillenbrand et al.
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