Diadochokinetic rate in Saudi and Bahraini Arabic speakers: Dialect and the influence of syllable type.

Arabic is spoken by more than 420 million people worldwide and still there are a limited number of studies on dialects of the Gulf Arabic regions where most selected respondents are male speakers. This study aimed to explore and establish normative data for the Diadochokinetic Rate (DDK) for two dialects (Saudi Arabia's Najdi and Bahrain's Bahraini) speakers. Furthermore, it aimed to investigate whether there are differences between the two dialects and whether sex differences are evident. In addition, it investigated syllable type differences. The study used the monosyllables /ba, da, ga/ and the multisyllabic sequence /badaga/ to analyse the DDK rates. Acoustic analysis was carried out to obtain DDK rates for the syllables. A mixed model ANOVA was performed to investigate dialect and sex differences, in addition, to syllable type. The study included 40 males and 40 female speakers from each of the two dialects. Results showed that for DDK, Saudi speakers had faster DDK rates for the monosyllables /ba/, /da/, /ga/, than Bahrainis, while, no significant differences were observed for the multisyllabic sequences. However, there were no differences between male and female speakers with regard to the DDK rates. The syllable /ga/ showed the slowest DDK rate among the monosyllables while the multisyllabic sequences displayed the slowest DDK rates. In brief, normative data for DDK rates for clinic were determined for the Arabic Nadji and Bahrain's Bahraini dialects. DDK rate was shown to be more sensitive to dialect differences for the monosyllable tasks. However, no sex differences were observed for the Arabic dialects in this study across all DDK tasks.

Analyses of Sustained Vowels in Down Syndrome (DS): A Case Study Using Spectrograms and Perturbation Data to Investigate Voice Quality in Four Adults With DS.

OBJECTIVES: Automatic acoustic measures of voice quality in people with Down syndrome (DS) do not reliably reflect perceived voice qualities. This study used acoustic data and visual spectral data to investigate the relationship between perceived voice qualities and acoustic measures. STUDY DESIGN: Participants were four young adults (two males, two females; mean age 23.8 years) with DS and severe learning disabilities, at least one of whom had a hearing impairment. METHODS: Participants imitated sustained /i/, /u/, and /a/ vowels at predetermined target pitches within their vocal range. Medial portions of vowels were analyzed, using Praat, for fundamental frequency, harmonics-to-noise ratio, jitter, and shimmer. Spectrograms were used to identify the presence and the duration of subharmonics at onset and offset, and mid-vowel. The presence of diplophonia was assessed by auditory evaluation. RESULTS: Perturbation data were highest for /a/ vowels and lowest for /u/ vowels. Intermittent productions of subharmonics were evident in spectrograms, some of which coincided with perceived diplophonia. The incidence, location, duration, and intensity of subharmonics differed between the four participants. CONCLUSIONS: Although the acoustic data do not clearly indicate atypical phonation, diplophonia and subharmonics reflect nonmodal phonation. The findings suggest that these may contribute to different perceived voice qualities in the study group and that these qualities may result from intermittent involvement of supraglottal structures. Further research is required to confirm the findings in the wider DS population, and to assess the relationships between voice quality, vowel type, and physiological measures.

Self-Administered Computer Therapy for Apraxia of Speech: Two-Period Randomized Control Trial With Crossover.

BACKGROUND AND PURPOSE: There is currently little evidence on effective interventions for poststroke apraxia of speech. We report outcomes of a trial of self-administered computer therapy for apraxia of speech. METHODS: Effects of speech intervention on naming and repetition of treated and untreated words were compared with those of a visuospatial sham program. The study used a parallel-group, 2-period, crossover design, with participants receiving 2 interventions. Fifty participants with chronic and stable apraxia of speech were randomly allocated to 1 of 2 order conditions: speech-first condition versus sham-first condition. Period 1 design was equivalent to a randomized controlled trial. We report results for this period and profile the effect of the period 2 crossover. RESULTS: Period 1 results revealed significant improvement in naming and repetition only in the speech-first group. The sham-first group displayed improvement in speech production after speech intervention in period 2. Significant improvement of treated words was found in both naming and repetition, with little generalization to structurally similar and dissimilar untreated words. Speech gains were largely maintained after withdrawal of intervention. There was a significant relationship between treatment dose and response. However, average self-administered dose was modest for both groups. Future software design would benefit from incorporation of social and gaming components to boost motivation. CONCLUSIONS: Single-word production can be improved in chronic apraxia of speech with behavioral intervention. Self-administered computerized therapy is a promising method for delivering high-intensity speech/language rehabilitation. CLINICAL TRIAL REGISTRATION: URL: http://orcid.org/0000-0002-1278-0601. Unique identifier: ISRCTN88245643.

The Relationship Between Apraxia of Speech and Oral Apraxia: Association or Dissociation?

Acquired apraxia of speech (AOS) is a motor speech disorder that affects the implementation of articulatory gestures and the fluency and intelligibility of speech. Oral apraxia (OA) is an impairment of nonspeech volitional movement. Although many speakers with AOS also display difficulties with volitional nonspeech oral movements, the relationship between the 2 conditions is unclear. This study explored the relationship between speech and volitional nonspeech oral movement impairment in a sample of 50 participants with AOS. We examined levels of association and dissociation between speech and OA using a battery of nonspeech oromotor, speech, and auditory/aphasia tasks. There was evidence of a moderate positive association between the 2 impairments across participants. However, individual profiles revealed patterns of dissociation between the 2 in a few cases, with evidence of double dissociation of speech and oral apraxic impairment. We discuss the implications of these relationships for models of oral motor and speech control.

Speech tempo and fundamental frequency patterns: a case study of male monozygotic twins and an age- and sex-matched sibling.

This case study describes an investigation into the speaking characteristics of a set of male monozygotic (MZ) twins (T1 and T2) and an age- and sex-matched sibling (S). Measures of speech tempo and fundamental frequency (F0) were analysed in the speech samples of a reading passage. Results showed significant between-sibling differences for sentence durations and F0 parameters; however, Euclidean distance (ED) measures revealed the smallest distances between the F0 parameters of the MZ twins. The smallest ED values were also observed between T1 and T2 for word durations, pause durations, all-voiced sample durations, and all the all-voiced sample F0 parameters. Greater similarities were observed across all three siblings for the speech tempo and dynamic F0 parameters.

Error reduction therapy in reducing struggle and grope behaviours in apraxia of speech.

We report an intervention study focused on the speech production difficulties present in acquired apraxia of speech (AOS). The intervention was a self-administered computer therapy that targeted whole word production and incorporated error reduction strategies. The effectiveness of the therapy was contrasted to that of a visuospatial sham computer program, and performance across treated words, and two sets of matched words, was assessed. Two groups of participants completed the study which employed a two-phase cross-over treatment design. Participants were randomly assigned to a speech first or sham first condition. Treatments were administered for six weeks, with a four week rest between interventions. Participants were assessed five times in total; twice at baseline, once following each of the intervention phases, and once following a lapse of eight weeks after the end of the second phase of intervention. The occurrence of accurate word production and speech characterised by struggle and groping behaviours was recorded on a repetition task. Participants showed significant gains in speech accuracy and fluency, and reductions in articulatory groping and struggle behaviours following the use of the speech program. These gains were largely maintained once the therapy was withdrawn.

Hormones and dichotic listening: evidence from the study of menstrual cycle effects.

This report presents evidence for changes in dichotic listening asymmetries across the menstrual cycle, which replicate studies from our laboratory and others. Increases in the right ear advantage (REA) were present in women at phases of the menstrual cycle associated with higher levels of ovarian hormones. The data also revealed correlations between hormone levels and behavioural measures of asymmetry. For example, the pre-ovulatory surge in luteinising hormone (LH) was related to a decrease in left ear scores, which comprised a key part of the cycle related shift in asymmetry. Further analysis revealed a subgroup of women who had not reached postovulatory status by days 18-25 of the cycle, as verified by low progesterone levels. These women showed laterality profiles at days 18-25 that looked more like the other women when measured at the periovulatory phase (i.e., days 8-11). Data were combined with those from a previous study to highlight the stability of effects. Results showed a distinct menstrual cycle related increase in asymmetry in the combined sample. This final comparison confirmed the nature of sex differences in dichotic listening as being dependent on hormone status in women.

Plasticity, permanence, and patient performance: study design and data analysis in the cognitive rehabilitation of acquired communication impairments.

Communication impairments such as aphasia and apraxia can follow brain injury and result in limitation of an individual's participation in social interactions, and capacity to convey needs and desires. Our research group developed a computerized treatment program which is based on neuroscientific principles of speech production (Whiteside and Varley, 1998; Varley and Whiteside, 2001; Varley, 2010) and has been shown to improve communication in people with apraxia and aphasia (Dyson et al., 2009; Varley et al., 2009). Investigations of treatment efficacy have presented challenges in study design, effect measurement, and statistical analysis which are likely to be shared by other researchers in the wider field of cognitive neurorehabilitation evaluation. Several key factors define neurocognitively based therapies, and differentiate them and their evaluation from other forms of medical intervention. These include: (1) inability to "blind" patients to the content of the treatment and control procedures; (2) neurocognitive changes that are more permanent than pharmacological treatments on which many medical study designs are based; and (3) the semi-permanence of therapeutic effects means that new baselines are set throughout the course of a given treatment study, against which comparative interventions or long term retention effects must be measured. This article examines key issues in study design, effect measurement, and data analysis in relation to the rehabilitation of patients undergoing treatment for apraxia of speech. Results from our research support a case for the use of multiperiod, multiphase cross-over design with specific computational adjustments and statistical considerations. The paper provides researchers in the field with a methodologically feasible and statistically viable alternative to other designs used in rehabilitation sciences.

Dichotic listening asymmetry: sex differences and menstrual cycle effects.

The impact of menstrual cyclicity and sex differences on dichotic listening was studied in 25 women and 20 men (aged 20-25 years). Dichotic listening was administered using consonant-vowel (CV) stimuli and tested across three attention conditions. Women were tested at two points in the menstrual cycle (Day 2-5: low oestrogen and progesterone/Low-EP; Day 18-25: high oestrogen and progesterone/High-EP). Men were tested once. Performance averaged across attention conditions was analysed for menstrual cycle and sex effects. Significant menstrual cycle phase effects were observed in women. At the High-EP phase women showed a greater right ear advantage (REA) compared to the Low-EP phase. Sex differences were found when dichotic listening asymmetry in men was compared to women at the Low-EP, but not the High-EP phase. In contrast to laterality effects, baseline perceptual performance (total right plus left ear response) was similar in men and women at both phases of the menstrual cycle. Results support a role for ovarian hormones in shaping laterality of speech perception in women. This study also emphasises the importance of considering menstrual cycle effects when evaluating sex differences in dichotic listening.

Adaptation of wavelet transform analysis to the investigation of biological variations in speech signals.

The purpose of this study was to adapt wavelet analysis as a tool for discriminating speech samples taken from healthy subjects across two biological states. Speech pressure waveforms were drawn from a study on effects of hormone fluctuations across the menstrual cycle on language functions. Speech samples from the vowel portion of the syllable 'pa', taken at the low- and high-hormone phases of the menstrual cycle, were extracted for analysis. Initial analysis applied Fourier transforms to examine the fundamental and formant frequencies. Wavelet analysis was used to investigate spectral differences at a more microbehavioural level. The key finding showed that wavelet coefficients for the fundamental frequency of speech samples taken from the high-hormone phase had larger amplitudes than those from the low-hormone phase. This study provided evidence for differences in speech across the menstrual cycle that affected the vowel portion of syllables. This evidence complements existing data on the temporal features of speech that characterise the consonant portion of syllables. Wavelet analysis provides a new tool for examination of behavioural differences in speech linked to hormonal variation.

Speech across the menstrual cycle: a replication and extension study.

Whiteside et al. [S.P. Whiteside, A. Hanson, P.E. Cowell, Hormones and temporal components of speech: sex differences and effects of menstrual cyclicity on speech, Neurosci. Lett. 367 (2004) 44-47] documented effects of menstrual cycle phase and sex on voice onset time (VOT) in naturally timed speech using whole words. VOT is a temporal component of speech that plays an important role in production and perception [L.L. Koenig, Laryngeal factors in voiceless consonant production in men, women, and 5-year-olds, J. Speech Lang. Hear. Res. 43 (2000) 1211-1228; A. Löfqvist, L.L. Koenig, R.S. McGowan, Vocal tract aerodynamics in /aCa/ utterances: measurements, Speech Commun. 16 (1995) 49-66; T.M. Nearey, B. Rochet, Effects of place of articulation and vowel context in VOT production and perception for French and English Stops, J. Int. Phon. Assoc. 24 (1994) 1-18; L.M. Rimol, T. Eichele, K. Hugdahl, The effect of voice-onset-time on dichotic listening with consonant-vowel syllables, Neuropsychologia 44 (2006) 191-196; P.G. Simos, R.L. Diehl, J.I. Breier, M.R. Molis, G. Zouridakis, A.C. Papanicolaou, MEG correlates of categorical perception of a voice onset time continuum in humans, Cogn. Brain Res. 7 (1998) 215-219; S.P. Whiteside, J. Marshall, Developmental trends in voice onset time: some evidence for sex differences, Phonetica 58 (2001) 196-210]. The present study was designed to replicate and expand upon Whiteside et al. [S.P. Whiteside, A. Hanson, P.E. Cowell, Hormones and temporal components of speech: sex differences and effects of menstrual cyclicity on speech, Neurosci. Lett. 367 (2004) 44-47] using a speeded syllable repetition paradigm. VOT measurements for 6 English plosives (/p b t d k g/) were obtained from speech samples of 15 women and 20 men (age 20-25 years). Women were tested across two points in the menstrual cycle (Days 2-5: low estrogen and progesterone/low-EP; Days 18-25: high estrogen and progesterone/high-EP) and men were tested once. Results indicated significant interaction between menstrual cycle phase and voicing (F(1,14)=8.239, P<0.02), whereby the voiced plosives (b, g) displayed shorter VOT values and the voiceless plosives (p, k) displayed longer values at the high-EP phase. Thus, the distinction between the voiced and voiceless plosive was enhanced at high-EP. Significant sex effects (F(1,33)=10.080, P<0.005) were seen with women at high-EP but not the low-EP phase having longer VOT values than men for voiceless plosives. Sex differences between the voiced and voiceless plosives were enhanced at the high-EP phase. This study indicates a role for activational ovarian hormones in regulating temporal features of speech in both whole words and speeded syllable repetition.

Sex differences in voice onset time: a developmental study of phonetic context effects in British English.

Voice onset time (VOT) data for the plosives /p b t d k g/ in two vowel contexts (/i a/) for 5 groups of 46 boys and girls aged 5; 8 (5 years, 8 months) to 13;2 years were investigated to examine patterns of sex differences. Results indicated that there was some evidence of females displaying longer VOT values than the males. In addition, these were found to be most marked for the data of the 13;2-year olds. Furthermore, the sex differences in the VOT values displayed phonetic context effects. For example, the greatest sex differences were observed for the voiceless plosives, and within the context of the vowel /i/.

Hormones and temporal components of speech: sex differences and effects of menstrual cyclicity on speech.

Voice onset time (VOT) is a salient acoustic parameter of speech which signals the 'voiced' and 'voiceless' status of plosives in English (e.g. the initial sound in 'bat' versus the initial sound in 'pat'). As a micro-temporal acoustic parameter, VOT may be sensitive to changes in hormones which may affect the neuromuscular systems involved in speech production. This study adopted a novel approach by investigating the effects of menstrual cycle phase and sex on VOT. VOT data representing the six plosives of English (/p b t d k g/) were examined for seven women (age 20-23 years) at two phases of the menstrual cycle (day 18-25: high estrogen and progesterone; day 2-5: low estrogen and progesterone). Results indicated that menstrual cycle phase had a significant interaction with the identity of the plosive (F (5,30) = 5.869, P < 0.002). Menstrual cycle phase also had significant effects on the contrasts between cognate voiced and voiceless plosives (F (1,6) = 11.444, P < 0.02); samples from the high hormone phase displayed an enhanced voiced/voiceless contrast. Subsequently, VOT data samples from the two phases of the menstrual cycle were compared with those from five men in order to explore sex differences at different phases of the menstrual cycle. Low hormone phase samples displayed no significant sex differences for either VOT values (F (1,10) = 2.085, P > 0.05), or the contrast between voiced and voiceless cognates (F (1,10) = 0.407, P > 0.05). In contrast, the high hormone phase VOT samples displayed significant plosive by sex interactions (F (5,50) = 4.442, P < 0.005). In addition, significant sex differences were found for the contrasts between cognate voiced and voiceless plosives (F (1,10) = 5.019, P < 0.05); the women displayed a more marked voiced/voiceless contrast. The findings suggest that ovarian hormones play some role in shaping some temporal components of speech.

Patterns of variability in voice onset time: a developmental study of motor speech skills in humans.

This study investigated the developmental patterns of variability in the speech parameter voice onset time (VOT) in 46 children. Five groups of children participated in the study as follows: (i) Group 1, aged 5 years 8 months (n=6); (ii) Group 2, 7 years 10 months (n=10); (iii) Group 3, 9 years 10 months (n=10); (iv) Group 4, 11 years 10 months (n=10); and (v) Group 5, 13 years 2 months (n=10). Coefficient of variation values were examined for the VOT values of both 'voiceless' (/p t k/) and 'voiced' (/b d g/) plosives to determine patterns of variability. Significant effects of age were revealed for both the voiceless and voiced plosives, and levels of variability levelled off for Group 4. The data suggest that although variability in VOT decreases with age, the presence of residual variability may be a prerequisite for the further refinement of motor speech skills.