Towards a Vocal and Acoustic Description of Kapa Haka

OBJECTIVE

The purpose of this study is to analyze the voice used in kapa haka, a contemporary indigenous vocal performance from New Zealand, which includes the well-known haka. This is the first study of its kind and is a preliminary investigation into the vocal and acoustic description of kapa haka. A significant goal of this study is to contribute ideas and potential definitions of vocal qualities to the community of kapa haka trainers that were specific to the genre. This strengths-based project raises up these vocal practices as legitimate and authentic colors within a vocal tradition that has seen generational learning disrupted by colonial interventions and is now flourishing within the community.

METHODS

Eight kapa haka performers (three females, five males) were involved in the study, they were all experienced performers; furthermore, two had formal classical voice training. They were individually recorded speaking and performing three different genres of kapa haka (mōteatea, waiata, and haka); all recordings were in te reo Māori (the Māori language). In addition, electroglottograph (EGG) signals were collected. An auditory-perceptual evaluation of the kapa haka voice was completed by three singer-researcher-pedagogues familiar with Western and non-western genres of singing. They all have experience appropriately collecting and analyzing data from indigenous communities, and they all understand the sociopolitical context of the vocal genre within the local colonial history. A specific evaluation instrument was created, and the results were validated. The acoustic and time-aligned EGG data was annotated at the phoneme level, and the signal analysis was performed in MATLAB. Averaged EGG pulses from /a/ segments were investigated, along with long-term average spectrums of the performances obtained from both the audio signal and the EGG signals.

RESULTS

The perceptual analysis suggests the biggest difference in vocal styles was between the haka and the other two genres (and speech). The acoustic and EGG results support these findings.

CONCLUSIONS

Common characteristics, perceptually and acoustically, were identified in the kapa haka performance styles across the eight performers.

A Computer-Based Tool for the Assessment of Voice Quality Through Visual Analogue Scales: VAS-Simplified Vocal Profile Analysis

In this study we propose a new tool for the perceptual assessment of voice quality. For its design, we have adapted the Simplified Vocal Profile Analysis so that the new tool features two main characteristics: (1) the ordinal scalar degrees of the original protocol are turned into a visual analog scale; and (2) the original paper-based version of the protocol is now a computer-based implementation. In order to assess the reliability of the new tool, five phoneticians listened to 12 different speakers and evaluated their voice quality using the proposed tool. Inter-rater agreement was then calculated using the Intraclass Correlation Coefficient. The results show that high agreement was reached for most of the perceptual settings of the protocol. Yet more investigations seem necessary into the continuous nature of the perceptual dimensions making up the voice quality of a speaker. As a preliminary approach to the graphical possibilities that the visual analog scale offers to the Simplified Vocal Profile Analysis, we explore the usefulness of multiple dot plots and propose an adaptation of the Bland-Altman plot to be used in pairwise comparisons. In this study, these visualization techniques are tested on two pairs of identical twins.

Effect of Impairment-Oriented and Function-Oriented Exercises on Mouth Function in Subjects with Systemic Sclerosis

PURPOSE

The aim of this study was to develop an exercise protocol to improve maximal mouth opening (MMO), tongue protrusion (Tprot), tongue strength (Tstren), and lip strength (Lstren), and to assess its effects on subjects with scleroderma.

METHODS

We performed four replicated single-system studies in a consecutive sample of subjects with scleroderma. An instrumented assessment measured MMO, Tprot, Tstren, and Lstren. Each day, subjects were assessed and performed orofacial exercises conducted by speech therapists. Treatments were first aimed at improving mouth physical characteristics by impairment-oriented exercises and then to improve skills with function-oriented exercises.

RESULTS

The mean phase differences between assessment and treatment phases across subjects were from 0.88 to 9.56 mm in MMO, from 2.03 to 12.3 mm in Tprot, from -0.12 to 5.35 N in Tstren, and from -0.84 to 5.19 N in Lstren. After treatment, 3 subjects crossed the 5th percentile discriminating normal from abnormal performances for both Tstren and Tprot, while this occurred in 2 subjects for MMO and Lstren.

CONCLUSIONS

The results of this study suggest that rehabilitation appears to be useful in reducing tongue and lip impairments and in improving oral functions in subjects with scleroderma.

The Impact of Dysarthria on Laypersons' Attitudes towards Adults with Cerebral Palsy

OBJECTIVE

This study investigated laypersons' attitudes towards adults with dysarthria due to cerebral palsy (CP). We aimed to explore the impact of the overall severity and of specific symptoms of dysarthria on laypersons' evaluations.

PATIENTS AND METHODS

Eighteen adults with dysarthria due to CP and 6 nondysarthric controls participated as speakers. The individuals with CP underwent dysarthria assessment based on a standardized tool. The results were compared to those of a listening experiment with 20 laypersons. A text passage spoken by all speakers was presented to the listeners, who provided their evaluations using rating scales specifically developed for this study. The tool addressed 3 dimensions of attitudes: (1) estimation of a speaker's cognitive-linguistic abilities; (2) attribution of personality and social characteristics, and (3) listeners' emotions and behavioral tendencies towards the speaker.

RESULTS

Severity of dysarthria was strongly correlated with the overall attitudes. Regression analyses identified different symptoms as predictors of the listeners' judgements.

CONCLUSION

Severity of dysarthria seems to have a major impact on laypersons' attitudes. Results suggest that speech symptoms may have a very specific influence on laypersons' evaluations. This may be important for clinical care, since symptoms with the most negative impact should be focused on in treatment.

Distinct patterns of imprecise consonant articulation among Parkinson's disease, progressive supranuclear palsy and multiple system atrophy

Distinct speech characteristics that may aid in differentiation between Parkinson's disease (PD), progressive supranuclear palsy (PSP) and multiple system atrophy (MSA) remain tremendously under-explored. Here, the patterns and degree of consonant articulation deficits across voiced and voiceless stop plosives in 16 PD, 16 PSP, 16 MSA and 16 healthy control speakers were evaluated using acoustic and perceptual methods. Imprecise consonant articulation was observed across all Parkinsonian groups. Voice onset time of voiceless plosives was more prolonged in both PSP and MSA compared to PD, presumably due to greater severity of dysarthria and slower articulation rate. Voice onset time of voiced plosives was significantly shorter only in MSA, likely as a consequence of damage to cerebellar structures. In agreement with the reduction of pre-voicing, MSA manifested increased number of voiced plosives misclassified as voiceless at perceptual evaluation. Timing of articulatory movements may provide important clues about the pathophysiology of underlying disease.

Euclidean Distances as measures of speaker similarity including identical twin pairs: A forensic investigation using source and filter voice characteristics

There is a growing consensus that hybrid approaches are necessary for successful speaker characterization in Forensic Speaker Comparison (FSC); hence this study explores the forensic potential of voice features combining source and filter characteristics. The former relate to the action of the vocal folds while the latter reflect the geometry of the speaker's vocal tract. This set of features have been extracted from pause fillers, which are long enough for robust feature estimation while spontaneous enough to be extracted from voice samples in real forensic casework. Speaker similarity was measured using standardized Euclidean Distances (ED) between pairs of speakers: 54 different-speaker (DS) comparisons, 54 same-speaker (SS) comparisons and 12 comparisons between monozygotic twins (MZ). Results revealed that the differences between DS and SS comparisons were significant in both high quality and telephone-filtered recordings, with no false rejections and limited false acceptances; this finding suggests that this set of voice features is highly speaker-dependent and therefore forensically useful. Mean ED for MZ pairs lies between the average ED for SS comparisons and DS comparisons, as expected according to the literature on twin voices. Specific cases of MZ speakers with very high ED (i.e. strong dissimilarity) are discussed in the context of sociophonetic and twin studies. A preliminary simplification of the Vocal Profile Analysis (VPA) Scheme is proposed, which enables the quantification of voice quality features in the perceptual assessment of speaker similarity, and allows for the calculation of perceptual-acoustic correlations. The adequacy of z-score normalization for this study is also discussed, as well as the relevance of heat maps for detecting the so-called phantoms in recent approaches to the biometric menagerie.

Reliability of the Italian INFVo scale and correlations with objective measures and VHI scores

The objective of this study was to evaluate the reliability of the INFVo scale and its relationship with objective measures and VHI scores in 40 native Italian-speaking patients with substitution voice. The maximum phonation time (MPT), diadochokinesis (DDK) of the three syllabic sequence [pa/ta/ka], reading of a passage and a single word repetition test were recorded. Each patient completed the Italian version of the VHI. Three speech-language pathologists blindly rated the recordings using the auditory perceptual INFVo scale; one listened and assessed the voice recording twice. The INFVo intra- and inter-rater reliability reached good values. Strong to moderate correlations between the INFVo scale scores and MPT, DDK, distortions in the repetition test, speech rate during reading and the functional subscale of the VHI were found. In conclusion, the INFVo scale is a reliable tool and can be recommended for the perceptual assessment of substitution voices in Italian speaking patients.