Jan van Doorn

Nasalance Levels in the Speech of Normal Australian Children

OBJECTIVE Nasalance scores have been shown to depend on the regional dialect of English spoken. Australian cleft palate clinics are increasingly making use of the Nasometer as part of their evaluation of velopharyngeal inadequacy. There are, however, no normative data for Australian English available as reference information. The objective of this study, therefore, was to obtain comprehensive nasalance data for a large group of Australian children, aged 4 to 9 years, for two standard nasalance passages (Zoo Passage and Nasal Sentences) and to investigate any gender or age differences within that age range. PARTICIPANTS The participants were 245 children (123 female, 122 male) ranging in age from 4 years, 0 months, to 9 years, 3 months. The children were recruited from a variety of schools and preschools across the Sydney metropolitan region. The children all spoke Australian English, and their hearing, articulation skills, and speech resonance were within normal limits. METHOD Mean nasalance scores were obtained for two speech passages that are used as standards for Nasometer testing (Zoo Passage and Nasal Sentences). In addition, the nasalance data were analyzed for any gender and age dependence, using separate analyses of variance for each speech passage. Five consecutive age groups were used to examine age dependence (4-, 5-, 6-, 7-, and 8-year-old children). RESULTS A mean score of 13.1 (SD, 5.9) was obtained for the Zoo Passage, and a mean of 59.6 (SD, 8.1) for the Nasal Sentences. The analysis of variance results indicated that, at a probability level of p < 0.01, there was no statistically significant age or gender dependence for either speech passage. CONCLUSION These normative nasalance data for children who speak Australian English will provide important reference information for clinicians who assess nasality disorders in cleft palate clinics in Australia.

Normative data on nasalance scores for Swedish as measured on the Nasometer: Influence of dialect, gender, and age

This study was conducted to establish normative nasalance values for Swedish speaking children as measured with the Nasometer™ II, and to investigate differences due to regional dialect, gender, and age. Two hundred and twenty healthy children aged 4–5, 6–7, and 9–11 years were included. Group mean nasalance scores for four speech stimuli were calculated and compared. There were no significant differences due to dialect or gender for children in the study. For age there was a significant difference on nasal sentences between the youngest group of children and the other two groups, age 4–5 vs age 6–7 (t = −2.844, p = .006) and for age 4–5 vs age 9–11 (t = −2.888, p = .005). The results from this study have both clinical significance for Swedish SLPs working with resonance disorders, and theoretical significance for linguists studying features of dialects and languages.

Comparison between perceptual assessments of nasality and nasalance scores.

BACKGROUND There are different reports of the usefulness of the Nasometer™ as a complement to listening, often as correlation calculations between listening and nasalance measurements. Differences between findings have been attributed to listener experience and types of speech stimuli. AIMS To compare nasalance scores from the Nasometer with perceptual assessments, for the same and different Swedish speech stimuli, using three groups of listeners with differing levels of experience in judging speech nasality. METHODS & PROCEDURES To compare nasalance scores and blinded listener ratings of randomized recordings using three groups of listeners and two groups of speakers. Speakers were either classified as having hypernasal speech or speech with typical speech resonance. Listeners were speech-language pathologists (SLPs) working predominantly with resonance disorders, other SLPs and untrained listeners. OUTCOMES & RESULTS Correlations (r(s)) between hypernasality ratings and nasalance scores for each listener group and speech stimuli were calculated. For both groups of SLPs all correlations between perceptual ratings and nasalance scores were significant at p= 0.01. The correlations between the nasalance scores and ratings by listeners in the SLP groups were higher than those for the untrained listener group regardless of stimulus type. Post-hoc Mann-Whitney U-tests showed that the only difference that was significant was expert SLP group versus untrained listener group. Secondly, correlations between perceptual ratings and oral stimulus nasalance scores were higher when the perceptual ratings were based on spontaneous speech rather than on the oral stimulus. However, a Wilcoxon signed rank test showed that the difference was not significant. A third finding was that correlations between oral stimulus nasalance scores and perceptual scores were higher than those between mixed stimulus nasalance scores and perceptual scores. A Wilcoxon signed rank test showed that the difference was significant. CONCLUSIONS & IMPLICATIONS The Nasometer might be useful for the SLP with limited experience in assessing resonance disorders in differentiating between hyper- and hyponasality. With listener reliability for ratings of hypernasality still being an issue, the use of a nasalance score as a complement to the perceptual evaluation will also aid the expert SLP. It will give an alternative way of quantifying speech resonance and might help in especially hard to judge cases.

Deep Brain Stimulation of Caudal Zona Incerta and Subthalamic Nucleus in Patients with Parkinson's Disease: Effects on Diadochokinetic Rate

The hypokinetic dysarthria observed in Parkinsons disease (PD) affects the range, speed, and accuracy of articulatory gestures in patients, reducing the perceived quality of speech acoustic output in continuous speech. Deep brain stimulation (DBS) of the subthalamic nucleus (STN-DBS) and of the caudal zona incerta (cZi-DBS) are current surgical treatment options for PD. This study aimed at investigating the outcome of STN-DBS (7 patients) and cZi-DBS (7 patients) in two articulatory diadochokinesis tasks (AMR and SMR) using measurements of articulation rate and quality of the plosive consonants (using the percent measurable VOT metric). The results indicate that patients receiving STN-DBS increased in articulation rate in the Stim-ON condition in the AMR task only, with no effect on production quality. Patients receiving cZi-DBS decreased in articulation rate in the Stim-ON condition and further showed a reduction in production quality. The data therefore suggest that cZi-DBS is more detrimental for extended articulatory movements than STN-DBS.

The contribution of polysyllabic words in clinical decision making about children's speech.

Poor polysyllabic word (PSW) production seems to mark paediatric speech impairment as well as impairment in language, literacy and phonological processing. As impairment in these domains may only manifest in PSWs, PSW production may provide unique information that is often excluded from clinical decision making because insufficient PSWs are included in speech tests. A 5‐stage model of PSW acquisition is described. The model, grounded in optimality theory, expresses a reciprocal relationship between the relaxation of markedness constraints and the contraction of faithfulness constraints from 12 months of age to adolescence. The markedness constraints that persist to the age of 7;11 years are associated with non‐final weak syllables and within‐word consonant sequences. Output changes are argued to reflect increasing specification of phonological representations with age, liberating information for motor planning and execution, resulting in increasingly accurate output. The clinical implications of PSWs in assessment and therapy are discussed.

Deep Brain Stimulation of Caudal Zona Incerta and Subthalamic Nucleus in Patients with Parkinson's Disease: Effects on Voice Intensity

Deep brain stimulation of the subthalamic nucleus (STN-DBS) in patients with Parkinsons disease (PD) affects speech inconsistently. Recently, stimulation of the caudal zona incerta (cZi-DBS) has shown superior motor outcomes for PD patients, but effects on speech have not been systematically investigated. The aim of this study was to compare the effects of cZi-DBS and STN-DBS on voice intensity in PD patients. Mean intensity during reading and intensity decay during rapid syllable repetition were measured for STN-DBS and cZi-DBS patients (eight patients per group), before- and 12 months after-surgery on- and off-stimulation. For mean intensity, there were small significant differences on- versus off-stimulation in each group: 74.2 (2.0) dB contra 72.1 (2.2) dB (P = .002) for STN-DBS, and 71.6 (4.1) dB contra 72.8 (3.4) dB (P = .03) for cZi-DBS, with significant interaction (P < .001). Intensity decay showed no significant changes. The subtle differences found for mean intensity suggest that STN-DBS and cZi-DBS may influence voice intensity differently.

Swallowing function in Parkinson's patients following Zona Incerta deep brain stimulation

The purpose of the present study was to examine whether there was a negative effect of caudal Zona Incerta deep brain stimulation (cZI DBS) on pharyngeal swallowing function in Parkinsons patients (PD). There are no former reports including swallowing and cZI DBS.

Vowel formant dispersion as a measure of articulation proficiency

The articulatory range of a speaker has previously been estimated by the shape formed by first and second formant measurements of produced vowels. In a majority of the currently available metrics, formant frequency measurements are reduced to a single estimate for a condition, which has adverse consequences for subsequent statistical testing. Other metrics provide estimates of size of vowel articulation changes only, and do not provide a method for studying the direction of the change. This paper proposes an alternative approach. Vowel formant frequencies are redefined as vectors originating from a defined center point of the vowel space fixed to a basic three-vowel frame. The Euclidean length of the vectors, the vowel formant dispersion (VFD), can be compared across conditions for evidence of articulatory expansions or reductions across conditions or speaker groups. Further, the angle component of the vowel vectors allows for analyses of direction of the reduction or expansion. Based on the range of investigations afforded by the VFD metric, and simulation experiments that compare its statistical properties with those of other proposed metrics, it is argued that the VFD procedure offers an enhanced view of vowel articulation change over rival metrics.

Perceived articulatory precision in patients with Parkinson’s disease after deep brain stimulation of subthalamic nucleus and caudal zona incerta

Abstract The effect of deep brain stimulation (DBS) of the subthalamic nucleus (STN) and caudal zona incerta (cZi) on speech articulation in patients with Parkinson’s disease (PD) was investigated. Read speech samples were collected from nine patients with STN-DBS and 10 with cZi-DBS. The recordings were made pre-operatively and 12 months post-operatively with stimulator on and off (on medication). Blinded, randomised, repeated perceptual assessments were performed on words and isolated fricatives extracted from the recordings to assess (1) overall articulatory quality ratings, (2) frequency of occurrence of misarticulation patterns and (3) fricative production. Statistically significant worsening of articulatory measures on- compared with off-stimulation occurred in the cZi-DBS group, with deteriorated articulatory precision ratings, increased presence of misarticulations (predominately altered realisations of plosives and fricatives) and a reduced accuracy in fricative production. A similar, but not significant, trend was found for the STN-DBS group.

Patterns of consonant deletion in typically developing children aged 3 to 7 years.

Children with and without speech, language and/or literacy impairment, delete consonants when they name pictures to elicit single words. Consonant deletion seems to be more frequent in long words (words of three or more syllables) than in short words (words of one or two syllables). However, it may be missed in long words because they are not routinely assessed and, even if they are, there is little normative data about them. The study aims were (1) to determine if a relationship exists between consonant deletion and the number of syllables in words, (2) delimit variation in the numbers of children using it, its frequency of occurrence and the words it affects and (3) to discuss the application of these data to clinical practice. The participants were 283 typically developing children, aged 3;0 to 7;11 years, speaking Australian English with proven normal language, cognition and hearing. They named pictures, yielding 166 selected words that were varied for syllable number, stress and shape and repeatedly sampled all consonants and vowels of Australian English. Almost all participants (95%) used consonant deletion. Whilst a relationship existed between consonant deletion frequency and the number of syllables in words, the syllable effect was interpreted as a proxy of an interaction of segmental and prosodic features that included two or more syllables, sonorant sounds, non-final weak syllables, within-word consonant sequences and/or anterior-posterior articulatory movements. Clinically, two or three deletions of consonants across the affected words may indicate typical behaviour for children up to the age of 7;11 years but variations outside these tolerances may mark impairment. These results are further evidence to include long words in routine speech assessment.