Objective: To evaluate esophageal speech quality in patients after total laryngectomy using cepstral, spectral and time-based measures. Patients and Methods: The subjects were all males and included 20 total laryngectomy patients and 20 age-matched normal controls. The sustained vowel /a/ was measured using the tools of MDVP (Multi-Dimensional Voice Program) and ADSV (Analysis of Dysphonia in Speech and Voice). Results: Compared to normal controls, esophageal speakers showed significantly lower values for cepstral peak prominence (CPP) and a low- to high-frequency spectral energy (L/H) ratio, but their mean CPP fundamental frequency (CPP F0) was higher. Highly negative correlations were found between CPP and jitter (percent jitter), shimmer (percent shimmer) and noise-to-harmonics ratio (NHR). Positive correlations were also found between L/H ratio and CPP. CPP F0 showed a positive correlation with F0, shimmer and NHR. In addition, CPP and L/H ratio parameters indicated an area under the curve of 0.93 or higher compared to that for time-based measures. Conclusion: This study showed that cepstral and spectral analyses are more effective than time-based analysis in examining the voice quality of alaryngeal speakers. The present findings are expected to contribute to establishing the baseline for voice quality characteristics in total laryngectomy patients.

The purpose of this study was to investigate the characteristics of speech intelligibility of spontaneous speech and the vowel space parameters in patients with Parkinson's disease. Ten PD patients (M=5, F=5) and a corresponding control group of ten normal adults participated in this study. Firstly, subjects were asked to tell a story about their hometown and youth in order to analyze speech intelligibility. Secondly, the subjects were also asked to repeat four vowels (/a/, /i/, /u/, /e/) five times in order to compare their vowel spaces. The results were as follows: (1) the speech intelligibility of the PD group was lower than that of the control group. (2) Four parameters including vowel area, vowel articulatory index, formant centralization ratio, F2i/F1u ratio were significantly different in each group. For instance, vowel area and F2 ratio were wider and higher, respectively. As a result, a decrease in speech intelligibility of patients with PD is likely to show different types of errors from the normal group. The results of this research are meaningful in a sense that they could provide the objective standard of speech intelligibility and vowel space parameters.

This study aimed to examine the cepstral and spectral acoustic features of patients with muscle tension dysphonia (MTD). Methods: A total of 30 patients with MTD and 30 healthy women (control group) were enrolled. All participants were asked to vocalize a sustained vowel /a/ for more than 3 seconds, which was recorded and analyzed using the Analysis of Dysphonia in Speech and Voice program. Results: Compared with the control group, patients with MTD had significantly lower cepstral peak prominence (CPP) and CPP F0, and significantly higher cepstral and spectral index of dysphonia (CSID) and a low-to high-frequency spectral energy ratio. Additionally, in patients with MTD, there was a high correlation between CPP and perceptual parameters such as grade, roughness, breathiness and strain. Receiver operating characteristic analysis found that a threshold of 11.815 for CSID achieved a good classification for MTD, with 73.3% sensitivity and specificity. Conclusions: By applying cepstral and spectral analysis and identifying the acoustic features of patients with MTD, this study demonstrated the feasibility and usefulness of cepstral parameters in clinical practice.

This research is aimed at finding the acoustic characteristics of different voice rehabilitation techniques, the electrolaryx (EL), standard esophageal (SE), and tracheoesophageal (TE), used on 17 patients with laryngectomees. The analysis of the voice qualities was achieved using MDVP. In order to compare the acoustic characteristics, patients were asked to produce the vowel /a/ sound. The acoustic analysis included fundamental frequency (f0), jitter, shimmer, and noise-to-harmonic ratio (NHR). The main acoustic results showed no significant statistical differences between the average measurements of SE and TE speakers. It was found that the current study showed the same tendency found in previous studies. There was also a significant difference between SE and EL speakers. On the other hand, there were no significant statistical differences between the average measurements of TE and EL speakers on all acoustic measurements. This research will contribute to establishing a baseline related to speech characteristics in voice rehabilitation for patients with laryngectomees. In future, the present findings and issues should be considered in the context of gender. Specifically, the number of women who are diagnosed with laryngeal cancer continues to rise and their acoustic characteristics may indeed differ from those of men.

The purpose of this study is to examine the acoustic characteristics of Parkinsonian speech, with respect to different utterance conditions, by employing acoustic/auditory-perceptual analysis. The subjects of the study were 15 patients (M=7, F=8) with Parkinson's disease who were asked to read out sentences under different utterance conditions (clear/casual). The sentences read out by each subject were recorded, and the recorded speech was subjected to cepstrum and spectrum analysis using Analysis of Dysphonia in Speech and Voice (ADSV). Additionally, auditory-perceptual evaluation of the recorded speech was conducted with respect to breathiness and loudness. Results indicate that in the case of clear speech, there was a statistically significant increase in the cepstral peak prominence (CPP), and a decrease in the L/H ratio SD (ratio of low to high frequency spectral energy SD) and CPP F0 SD values. In the auditory-perceptual evaluation, a decrease in breathiness and an increase in loudness were noted. Furthermore, CPP was found to be highly correlated to breathiness and loudness. This provides objective evidence of the immediate usefulness of clear speech intervention in improving the voice quality of Parkinsonian speech.