Verbal ability in postmenopausal women in relation to age, cognitive and reproductive factors.

Word-finding difficulties have been associated with age and, in women, lowered sex hormone levels following menopause. However, there is limited understanding of the ways that specific aspects of word-finding are shaped by women's age, reproductive histories, and background factors such as education. The current study investigated the effects of age, cognitive and reproductive factors on word-finding abilities in 53 healthy postmenopausal women aged 48-79. A questionnaire was used to gather demographic information and reproductive history. A battery of verbal fluency, continuous series, and naming tasks was designed to assess word-finding across different sensory modalities and cognitive demands. Category and letter fluency were quantified as total number of correct words produced on each task. For continuous series, switch rates and switch costs were computed. For the naming tasks, accuracy and latency measures were used. There were three key findings. Firstly, there was a consistent positive association between education and all word-finding measures, i.e., verbal fluency, continuous series, and naming. Secondly, age-related declines were seen on tasks heavily dependent on working memory such as the continuous series task. Thirdly, reproductive factors across the lifespan such as age at menarche and reproductive years showed subtle effects on naming abilities, but not on verbal fluency or continuous series. The results highlight that word-finding abilities in healthy postmenopausal women are shaped by factors associated with their early years (education, age at menarche) and later adult life (age, reproductive years). The study also distinguished between the more global effects of education, and the more task-specific associations with age and reproductive variables, on verbal task performance after menopause.

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.

Handedness and the Corpus Callosum: A Review and Further Analyses of Discordant Twins.

Handedness effects with respect to regional corpus callosum (CC) anatomy remain open to question. Midsagittal CC tracings were obtained from structural MRIs in 21 female monozygotic twin pairs with discordant handedness (MZHd). The CC was divided into 99 percentile widths which were grouped into seven regions based on Denenberg's (1989, 1991b) factor analysis. Results showed that left handed (LH) twins had significantly larger regional widths in CC region W22-39 compared to right handed (RH) twins, an effect present in 19/21 MZHd pairs. Cross-study analyses revealed CC W22-39 to have the highest variation across female singletons (Cowell et al., 1992, 1993). In the adjacent genu region (W3-18), CC size did not differ between RH and LH twins. However, when twins were reclassified according to handedness direction and consistency to form consistent RH, non-consistent RH, consistent LH and non-consistent LH groups, patterns of CC size in W3-18 closely matched those of singleton women (Cowell et al., 1993). Namely, CC W3-18 was larger in consistent compared to non-consistent RHs. Results support a claim that CC region W22-39, interconnecting premotor cortex in females, provides for environmentally influenced components of handedness, given the difference within MZHd twin pairs. By contrast, CC W3-18, connecting prefrontal cortex, was sensitive to direction and consistency of handedness, both in twins and singletons, a result consistent with combined genetic and environmental effects. Findings highlight the significance of MZHd twin studies in elucidating the developmental mechanisms underpinning structure-function asymmetry, cortical interconnectivity and neurodevelopmental bases of left hand preference.

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.

Quantification of structural changes in the corpus callosumin children with profound hypoxic-ischaemic brain injury.

BACKGROUND: Birth-related acute profound hypoxic-ischaemic brain injury has specific patterns of damage including the paracentral lobules. OBJECTIVE: To test the hypothesis that there is anatomically coherent regional volume loss of the corpus callosum as a result of this hemispheric abnormality. MATERIALS AND METHODS: Study subjects included 13 children with proven acute profound hypoxic-ischaemic brain injury and 13 children with developmental delay but no brain abnormalities. A computerised system divided the corpus callosum into 100 segments, measuring each width. Principal component analysis grouped the widths into contiguous anatomical regions. We conducted analysis of variance of corpus callosum widths as well as support vector machine stratification into patient groups. RESULTS: There was statistically significant narrowing of the mid-posterior body and genu of the corpus callosum in children with hypoxic-ischaemic brain injury. Support vector machine analysis yielded over 95% accuracy in patient group stratification using the corpus callosum centile widths. CONCLUSION: Focal volume loss is seen in the corpus callosum of children with hypoxic-ischaemic brain injury secondary to loss of commissural fibres arising in the paracentral lobules. Support vector machine stratification into the hypoxic-ischaemic brain injury group or the control group on the basis of corpus callosum width is highly accurate and points towards rapid clinical translation of this technique as a potential biomarker of hypoxic-ischaemic brain injury.

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.

Discordant cerebral lateralisation for verbal fluency is not an artefact of attention: evidence from MzHd twins.

The current study investigated how the brain structure-function relationships between covert and overt verbal fluency in monozygotic handedness discordant (MzHd) twins relates to broader attentional measures. Evidence presented here shows that the structure-function correlation demonstrated between functional cerebral lateralisation and corpus callosum widths 22-39, contiguous with Broca's area and the middle frontal gyri (Gurd et al. in Brain Struct Funct 218:491-509, 2013), is not an artefact of attention. Twenty-five pairs of female MzHd twins performed a verbal switching task titrated for number of switches. The paradigm permits calculation of switch rates and costs. The switch rate and cost varied as a function of number of switches (1, 2, 3). There were no differences in any measure in relation to right-left handedness in twin pairs. This was supported by large and significant within-twin pair correlations. Atypical functional lateralisation of inferior and middle frontal lobes does not appear to be associated with better or worse performance on verbal task-switching. Discordant lateralisation for verbal fluency does not predict behavioural performance profiles in MzHd twins. This evidence is compatible with a view that attentional components of verbal fluency task performance may have significant heritable components. It does not indicate that neural correlates of frontal cerebral laterality for verbal fluency in MzHd twins are significantly accountable for by heritable components.

Artificial grammar learning in individuals with severe aphasia.

One factor in syntactic impairment in aphasia might be damage to general structure processing systems. In such a case, deficits would be evident in the processing of syntactically structured non-linguistic information. To explore this hypothesis, we examined performances on artificial grammar learning (AGL) tasks in which the grammar was expressed in non-linguistic visual forms. In the first experiment, AGL behavior of four aphasic participants with severe syntactic impairment, five aphasic participants without syntactic impairment, and healthy controls was examined. Participants were trained on sequences of nonsense stimuli with the structure A(n)B(n). Data were analyzed at an individual level to identify different behavioral profiles and account for heterogeneity in aphasic as well as healthy groups. Healthy controls and patients without syntactic impairment were more likely to learn configurational (item order) than quantitative (counting) regularities. Quantitative regularities were only detected by individuals who also detected the configurational properties of the stimulus sequences. By contrast, two individuals with syntactic impairment learned quantitative regularities, but showed no sensitivity towards configurational structure. They also failed to detect configurational structure in a second experiment in which sequences were structured by the grammar A(+)B(+). We discuss the potential relationship between AGL and processing of word order as well as the potential of AGL in clinical practice.

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.

Individual behavior in learning of an artificial grammar.

Artificial grammar learning (AGL) is a widely used experimental paradigm that investigates how syntactic structures are processed. After a familiarization phase, participants have to distinguish strings consistent with a set of grammatical rules from strings that violate these rules. Many experiments report performance solely at a group level and as the total number of correct judgments. This report describes a systematic approach for investigating individual performance and a range of different behaviors. Participants were exposed to strings of the nonfinite grammar A( n )B( n ). To distinguish grammatical from ungrammatical strings, participants had to pay attention to local dependencies while comparing the number of stimuli from each class. Individual participants showed substantially different behavioral patterns despite exposure to the same stimuli. The results were replicated across auditory and visual sensory modalities. It is suggested that an analysis that looks at individual differences grants new insights into the processes involved in AGL. It also provides a solid basis from which to investigate sequence-processing abilities in special populations, such as patients with neurological lesions.

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.

A new set of 84 colored nonobjects.

In this article, we present 84 nonobjects we created by using the colored object pictures from Rossion and Pourtois (2004). These nonobjects were explored on a number of measures, including object resemblance, visual complexity, and an object decision task (ODT). Object resemblance for nonobjects is a construct comparable to the "word-likeness" of phonotactically legal pseudowords. The nonobjects were rated as possible objects, showing similarity to real objects. Visual complexity ratings for objects and nonobjects were comparable. In the ODT, response times (RTs) were significantly longer for nonobjects than for real-object pictures. This RT difference is analogous to the word advantage, or lexicality effect, found in lexical decision tasks, in which responses for words are generally faster than those for nonwords. This nonobject set is freely available and has the advantage of having a companion set of real-object pictures. The nonobjects are available in color and in grayscale from brm.psychonomic-journals.org/content/supplemental.

A cross-language study of verbal and visuospatial working memory span.

This cross-language study of working memory compared 30 English speakers and 30 Mandarin Chinese speakers on backward and forward digit and spatial span. Mandarin speakers had greater spans on forward digit and spatial span than did English speakers. Effects were most significant for digit span where the mean score of the English speakers was equivalent to the lowest individual score from Mandarin speakers. Shorter articulation time for digits in spoken Mandarin may account for higher digit spans than those observed in English. The current study indicates that clinical applications of working memory tests should consider cross-language effects, particularly in the evaluation of verbal working memory deficits.

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.

Effects of sex and age on regional prefrontal brain volume in two human cohorts.

This study examined interactive effects of sex and age on prefrontal brain anatomy in humans. It specifically targeted ranges of the adult life span and regions of cortex that previously showed male-female differences. Participants were 68 healthy human males and females aged 20-72 years. Data collection and analysis were conducted in parallel across two cohorts (laboratories) to investigate reproducibility of effects in relation to sex and age. Volumes for four regional prefrontal subfields per hemisphere were obtained from high-resolution MRI. Regional sex by age interactions were replicated across cohorts. In men, age effects were greatest in medial prefrontal volume, with decreases in dorsal medial and orbital medial regions. In women, age-related changes in medial prefrontal regions were limited to the dorsal volume, with additional decreases observed in lateral subfields. Cohort and Cohort x Age effects in total brain and total prefrontal volume were linked to a combination of methodological and sampling-related factors. Findings indicated that neuroanatomical changes throughout adulthood unfold along different time scales in men and women. Results also showed that sex differences in ageing localized to medial prefrontal regions were particularly robust to variation across cohorts.

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.

A combined clinical, neuropsychological, and neuroanatomical study of adults with high functioning autism.

INTRODUCTION: Three hypotheses concerning associations between neuroanatomical abnormalities, neuropsychological impairments, and the behavioural manifestations of autism were investigated. The primary hypothesis was that the social interaction impairments diagnostic of autism are associated with deficits of socioemotional perception and abnormalities of the amygdala. One subsidiary hypothesis was that the learning and language impairments that occur in less able individuals with autism are associated with impaired memory, and with abnormalities of hippocampal regions. A second subsidiary hypothesis was that the repetitive behaviour diagnostic of autism is associated with executive deficits and with abnormalities of the prefrontal cortex. Associations between the neuroanatomical regions investigated were also examined. METHODS: Ten adult males with high functioning autism (HFA) were compared with 10 healthy controls matched for age, sex, verbal and nonverbal ability. Hypothesis-driven structural MRI and neuropsychological tests were used to collect neuroanatomical and neuropsychological data on all subjects. A version of the Wing Autism Diagnostic Interview Checklist was used to collect clinical data on the HFA subjects. RESULTS: Strong convergent evidence in support of the amygdala hypothesis was obtained, and preliminary support for the hippocampal/parahippocampal hypothesis. No clear evidence was obtained in support of the prefrontal hypothesis. Patterns of associations amongst volume measures within and between medial temporal and prefrontal regions suggest stronger within-region and weaker between-region associations in the HFA group compared with controls. CONCLUSIONS: These findings are discussed in terms of a model of autism in which selective abnormalities of the amygdala and hippocampus (in all cases) and of the parahippocampal gyrus (in lower functioning cases) are implicated, and in which a disruption of coordinated limbic and prefrontal activity may be critical.

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.