Browsing by Author "Lal, BK"
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Publication Does short-term endotracheal intubation affects the acoustic characteristics?(Kathmandu University, 2010) KC,Toran; Lal, BKAbstract Introduction: Endotracheal intubation can produce various degrees of temporary and sometimes permanent damage to the laryngotracheal mechanism. Recent development of computer based voice analysis technology can now detect a minute changes in acoustic waveforms which a normal human ear cannot. In the study we compared and analyzed the acoustic waveforms of 35 patients undergoing surgery under intubation anaesthesia. Objective: The aim of the present series is to analyze the effects of short term intubation with computerized voice laboratory. Materials and methods: Values of acoustic waveforms obtained from 35 patients were compared 48 hours after the short term endotracheal intubation anaesthesia. The comparisons were made in terms of perturbation (jitter and shimmer), harmonic- to noise ratio (HNR) and fundamental frequency (F0). Results: The pre-intubated voice characteristics when compared with the post-intubation group did not reveal any statistical difference (P>0.05). However, there was only a minimal decrease in F0 . Conclusion: The study revealed that, short term intubation anaesthesia does not alter the acoustic characteristics. The analysis of acoustic waveforms is a non invasive technique that helps to evaluate the effects of tracheal intubation on laryngeal function, a technique that warrants further evaluation. Key words: Acoustic characteristics, Endotracheal intubation, VoicePublication Objective analysis of voice in normal young adults(Kathmandu University, 2009) KC, Toran; Lal, BKAbstract Background: Acoustic vocal parameters measure frequency, intensity (amplitude), perturbation (jitter and shimmer) and dynamic range of the voicing vocal folds. Studies have established that a normal standard data is necessary for acoustic analysis. Objective: The aim of the present study is to standardise Jitter, shimmer, harmonic to noise ratio (HNR) and fundamental frequency (F0) for young adults with normal voice. Materials and methods: Values for acoustic voice measurements were obtained from 50 normal individuals with equal number of sexes, without sign and symptoms of voice problems. The vocal data measurement was performed with Doctor Speech (DRS) Tiger Electronics, USA. Results: Voice analyses were performed with a sustained vowel //i//. The jitter and HNR values were same [1.6 %( ±0.47/±0.43) and 25.8dB (±2.62/±2.72)] for both the genders. For the males, the jitter was 0.14% (±0.02) and 0.16%(±0.04) for female gender. There was a significant difference in the HNR (P=0.000) with 170.05HZ (±32.78) and 246.45HZ (±39.73) respectively for male and female genders. Conclusion: Our results differ from the various literatures; therefore it is important to standardise the program that we use before applying the values for tests designed for a different kind of population. Key words: Acoustic analysis, Perturbation, harmonics to noise ratio, fundamental frequency, standardised voice.Publication Objective voice analysis for vocal polyps following microlaryngeal phonosurgery(Kathmandu University, 2010) KC, Toran; Lal, BKAbstract Background: Vocal polyps are the products of voice overuse, misuse and abuse as the most common causative factors. Treatment generally advised for them are voice therapy and Microlaryngeal Phonosurgery (MLPS). The improved or changed quality of voice is generally assessed perceptually and can cause intra rater variability. In this study we compared and analysed the acoustic characteristics before and after MLPS. Objective: The purpose of the study was to acoustically determine the changes in voice quality of a group of patients before and after the surgery. Material and methods: The following patients group were studied prior to and in between 3 and 4 weeks of surgery. Altogether there were 23 patients with either unilateral or bilateral vocal polyps. Voice recording and analysis were performed with Dr. Speech acoustic software (Tiger electronics, USA). The parameters analyzed were in terms of perturbation (Jitter and shimmer), harmonic-to-noise ratio (HNR) and fundamental frequency (F0 ). Results: The results showed that shimmer, HNR and F0 decreased significantly (p<0.05) following MLPS, but jitter though reduced, was not statistically significant (p=0.694). Conclusion: The acoustic output generally improved after MLPS as evidenced by decreased values of all the four acoustic parameters. The study also stress that voice quality can be improved through the phonosurgical procedures. This multidimensional voice analysis can be very helpful in our ability to provide objective clinical analysis of voices with vocal polyps, and following their surgical treatment. Key words: Acoustic analysis, Vocal polyps, Micro-laryngeal phonosurgery