Journal of Voice : official journal of the Voice Foundation, Sep 2014
Objective
The shape of the vocal tract and associated structures (e.g. tongue and velum) is comp... more Objective
The shape of the vocal tract and associated structures (e.g. tongue and velum) is complicated and varies according to development and function. This variability challenges interpretation of voice experiments. Quantifying differences between shapes and understanding how vocal structures move in relation to each other is difficult using traditional linear and angle measurements. With statistical shape models, shape can be characterized in terms of independent modes of variation. Here, we build an active shape model (ASM) to assess morphological and pitch-related functional changes affecting vocal structures and the airway.
Method
Using a cross-sectional study design, we obtained 6 midsagittal MR images from 10 healthy adults (5 males and five females) at rest, while breathing out, and while listening to and humming low and high notes. Eighty landmark points were chosen to define the shape of interest and an ASM was built using these (60) images. Principal component analysis was used to identify independent modes of variation and statistical analysis was performed using one-way repeated-measures ANOVA.
Results
Twenty modes of variation were identified with modes 1 and 2 accounting for half the total variance. Modes 1 and 9 were significantly associated with humming low and high notes (P < 0.001) and showed coordinated changes affecting the cervical spine, vocal structures and airway. Mode 2 highlighted wide structural variations between subjects.
Conclusion
This study highlights the potential of active shape modelling to advance understanding of factors underlying morphological and pitch-related functional variations affecting vocal structures and the airway in health and disease.
Journal of Voice: official journal of the Voice Foundation, Jan 2012
Objectives / Hypothesis
Traditional voice research occurs within a phonetic context. Accordingly... more Objectives / Hypothesis
Traditional voice research occurs within a phonetic context. Accordingly, pitch-related contributions are inseparable from those due to articulator input. In humming, articulator input is negligible. Using MRI we test the hypothesis that voice production is accompanied by pitch-related adjustments unrelated to articulatory or postural input.
Study Design / Method
In this cross-sectional study, 10 healthy volunteers (5 males, 5 females, age 20-47, median 25 years) including singers (6 months-10 years tuition, median 2 years) and non-singers, were assessed to establish the lowest and highest notes they could comfortably sustain while humming over 20 seconds. With head position stable, mid-sagittal images were acquired while volunteers hummed these predetermined low and high notes. 22 craniocervical, angular and linear dimensions defined on these images were compared using One Way Repeated Measures ANOVA. Correlations between variables were sought using Pearson’s correlation coefficient.
Results
We found significant differences between low and high note conditions in 6/22 measures and widespread pitch-related correlations between variables (r ≥ 0.66, P < 0.05). Compared with low note humming, high note humming was accompanied by increased craniocervical angles opt/nsl and cvt/nsl (P = 0.008 and 0.002 respectively); widening of the C3-menton distance (P = 0.003), a rise of the larynx and hyoid in relation to the cranial base (P = 0.012 and < 0.001 respectively) and a decreased sternum-hyoid distance (P = 0.004).
Conclusion
Voice production is accompanied by pitch-related adjustments that are currently being masked by, or mistakenly attributed to, articulatory or postural input, identification of which could improve understanding of mechanisms underlying speech and song.
Journal of Voice: official journal of the Voice Foundation, Jan 2012
Objectives
Traditional voice research focuses upon the vocal tract, articulators and larynx. By ... more Objectives
Traditional voice research focuses upon the vocal tract, articulators and larynx. By ignoring their direct/indirect attachments (skull, cervical spine, sternum) important information may be missed. We aim to investigate vocal structures within this wider context and assess the validity of this approach for subsequent voice production studies.
Study Design / Method
Using a cross-sectional study design we obtained mid-sagittal MR images from ten healthy adults (5 males, 5 females) while at rest and breathing quietly. With reference points based upon cephalometry, 17 craniocervical, craniocaudal and antero-posterior variables were chosen to describe craniofacial morphology, craniocervical posture and airway dimensions. Relationships between variables were sought using Pearson’s correlation coefficient.
Results
We found widespread correlations relating vocal structures to the craniofacial skeleton and cervical spine (r > 0.6). Increasing airway size (hyocervical distance) was associated with greater distances from the cranial base of the hyoid, larynx, epiglottis tip and uvula tip, and of C3 from the menton. A wider velopharyngeal opening was associated with a shorter and higher soft palate, and a greater (lower) craniocervical angle was associated with a wider laryngeal tube opening, narrower airway at the uvula tip and shorter distances of the hyoid and uvula tip from the cranial base.
Conclusion
Finding widespread correlations relating vocal structures to the craniofacial skeleton and cervical spine confirms the potential of this approach to uncover functional activity during voice production and demonstrates the importance of considering vocal structures and the airway within this wider context if important information is not to be missed.
Keywords
MRI-Cephalometry-Vocal Tract-Speech-Posture
Purpose. There is a continuing need to improve the prediction of hip fractures to identify those ... more Purpose. There is a continuing need to improve the prediction of hip fractures to identify those at highest risk, enabling cost-effective use of preventative therapies.
Traditional voice research occurs within a phonetic context. Accordingly, pitch-related contribut... more Traditional voice research occurs within a phonetic context. Accordingly, pitch-related contributions are inseparable from those due to articulator input. In humming, articulator input is negligible. Using MRI we test the hypothesis that voice production is accompanied by pitch-related adjustments unrelated to articulatory or postural input.
The shape of the lumbar spine in the sagittal plane varies between individuals and as a result of... more The shape of the lumbar spine in the sagittal plane varies between individuals and as a result of postural changes but it is not known how the shape in different postures is related. Sagittal images of the lumbar spines of 24 male volunteers were acquired using a positional magnetic resonance scanner. The subjects were imaged lying supine, standing and sitting. An active shape model was used to characterize shape in terms of independent modes of variation. Two modes were identified that described the total (mode 1) and distribution (mode 2) of the curvature. The spinal shape was found to be intercorrelated between the three postures for both modes, suggesting that the lumbar spine has an element of shape that is partially maintained despite postural alterations. Mode 1 values indicated that the spine was straightest when standing and curviest when sitting. Mode 2 values indicated that the distribution in the curvature was most even when sitting and least even when lying supine. Systematic differences in the behaviour of the spine, when changing posture, were found that suggest that the shape of the spine may affect its biomechanics.
Determining the effect of load carriage on the human spine in vivo is important for determining s... more Determining the effect of load carriage on the human spine in vivo is important for determining spinal forces and establishing potential mechanisms of back injury. Previous studies have suggested that the natural curvature of the spine straightens under load, but are based on modelling and external measurements from the surface of the back. In the current study, an upright positional MRI scanner was used to acquire sagittal images of the lumbar and lower thoracic spine of 24 subjects. The subjects were imaged in standing whilst supporting 0, 8 and 16 kg of load which was applied axially across the shoulders using an apron. An active shape model of the vertebral bodies from T10 to S1 was created and used to characterise the effect of load. The results from the shape model showed that the behaviour of the average-shaped spine was to straighten slightly. However, the shape model also showed that the effect of load exhibited systematic variation between individuals. Those who had a smaller than average curvature before loading straightened under load, whereas those who had a greater than average curvature before loading showed an increase in curvature under load. The variation in behaviour of differently shaped spines may have further implications for the effects of load in lifting manoeuvres and in understanding the aetiology of back pain.
Nuclear magnetic resonance is increasingly recognised as a means of assessing attributes of f... more Nuclear magnetic resonance is increasingly recognised as a means of assessing attributes of foodstuffs. Usually this has meant removing samples for testing in laboratories, often some distance from the site of food production, using large and expensive equipment. Here we present some preliminary results demonstrating the use of a small device using single-sided magnets that could, in principle, be made portable. Ripening of fruit, water content in chicken and anisotropic properties of asparagus and tendon are used as examples of measurements that have been made previously using conventional instruments. The results show that data can be obtained rapidly and that the new method of testing could be extended to non-invasive measurements on larger objects.
BMC Medical Imaging , 4:4, 2004
Background
This study presents an analysis of trabecular bone s... more BMC Medical Imaging , 4:4, 2004
Background
This study presents an analysis of trabecular bone structure in standard radiographs using Fourier transforms and principal components analysis (PCA) to identify contributions to hip fracture risk. Methods
Radiographs were obtained from 26 hip fracture patients and 24 controls. They were digitised and five regions of interest (ROI) were identified from the femoral head and neck for analysis. The power spectrum was obtained from the Fourier transform of each region and three profiles were produced; a circular profile and profiles parallel and perpendicular to the preferred orientation of the trabeculae. PCA was used to generate a score from each profile, which we hypothesised could be used to discriminate between the fracture and control groups. The fractal dimension was also calculated for comparison. The area under the receiver operating characteristic curve (Az) discriminating the hip fracture cases from controls was calculated for each analysis. Results
Texture analysis of standard radiographs using the fast Fourier transform yielded variables that were significantly associated with fracture and not significantly correlated with age, body mass index or femoral neck bone mineral density. The anisotropy of the trabecular structure was important; both the perpendicular and circular profiles were significantly better than the parallel-profile (P < 0.05). No significant differences resulted from using the various ROI within the proximal femur. For the best three groupings of profile (circular, parallel or perpendicular), method (PCA or fractal) and ROI (Az = 0.84 – 0.93), there were no significant correlations with femoral neck bone mineral density, age, or body mass index. PCA analysis was found to perform better than fractal analysis (P = 0.019). Conclusions
Both PCA and fractal analysis of the FFT data could discriminate successfully between the fracture and control groups, although PCA was significantly stronger than fractal dimension. This method appears to provide a powerful tool for the assessment of bone structure in vivo with advantages over standard fractal methods.
Hip fracture due to osteoporosis (OP) and hip osteoarthritis (OA) are both important causes of lo... more Hip fracture due to osteoporosis (OP) and hip osteoarthritis (OA) are both important causes of locomotor morbidity in the elderly population. In osteoporosis, bone mass gradually decreases until the skeleton is too fragile to support the body and a fracture occurs, typically in the femur, wrist, or spine. In osteoarthritis, there is a proliferation of bone, leading to a stiffening of the tissue. Current clinical methods for assessment of bone changes in these disorders largely depend on assessing bone mineral density. However, this does not provide any information about bone structure which is considered to be an equally important factor in assessing bone quality. This paper presents a novel approach for computer analysis of trabecular (or cancellous) bone structure. The technique uses a Fourier transform to generate a "spectral fingerprint" of an image. Principal components analysis is then applied to identify key features from the Fourier transform and this information passed to a neural network for classification. Testing this on a series of 100 histological sections of trabecular bone from patients with OP and OA and a normal group correctly classified over 90% of the OP group with an overall accuracy of 77%-84%. Such high success rates on a small group suggest that this may provide a simple, but powerful, method for identifying alterations in bone structure.
Journal of Voice : official journal of the Voice Foundation, Sep 2014
Objective
The shape of the vocal tract and associated structures (e.g. tongue and velum) is comp... more Objective
The shape of the vocal tract and associated structures (e.g. tongue and velum) is complicated and varies according to development and function. This variability challenges interpretation of voice experiments. Quantifying differences between shapes and understanding how vocal structures move in relation to each other is difficult using traditional linear and angle measurements. With statistical shape models, shape can be characterized in terms of independent modes of variation. Here, we build an active shape model (ASM) to assess morphological and pitch-related functional changes affecting vocal structures and the airway.
Method
Using a cross-sectional study design, we obtained 6 midsagittal MR images from 10 healthy adults (5 males and five females) at rest, while breathing out, and while listening to and humming low and high notes. Eighty landmark points were chosen to define the shape of interest and an ASM was built using these (60) images. Principal component analysis was used to identify independent modes of variation and statistical analysis was performed using one-way repeated-measures ANOVA.
Results
Twenty modes of variation were identified with modes 1 and 2 accounting for half the total variance. Modes 1 and 9 were significantly associated with humming low and high notes (P < 0.001) and showed coordinated changes affecting the cervical spine, vocal structures and airway. Mode 2 highlighted wide structural variations between subjects.
Conclusion
This study highlights the potential of active shape modelling to advance understanding of factors underlying morphological and pitch-related functional variations affecting vocal structures and the airway in health and disease.
Journal of Voice: official journal of the Voice Foundation, Jan 2012
Objectives / Hypothesis
Traditional voice research occurs within a phonetic context. Accordingly... more Objectives / Hypothesis
Traditional voice research occurs within a phonetic context. Accordingly, pitch-related contributions are inseparable from those due to articulator input. In humming, articulator input is negligible. Using MRI we test the hypothesis that voice production is accompanied by pitch-related adjustments unrelated to articulatory or postural input.
Study Design / Method
In this cross-sectional study, 10 healthy volunteers (5 males, 5 females, age 20-47, median 25 years) including singers (6 months-10 years tuition, median 2 years) and non-singers, were assessed to establish the lowest and highest notes they could comfortably sustain while humming over 20 seconds. With head position stable, mid-sagittal images were acquired while volunteers hummed these predetermined low and high notes. 22 craniocervical, angular and linear dimensions defined on these images were compared using One Way Repeated Measures ANOVA. Correlations between variables were sought using Pearson’s correlation coefficient.
Results
We found significant differences between low and high note conditions in 6/22 measures and widespread pitch-related correlations between variables (r ≥ 0.66, P < 0.05). Compared with low note humming, high note humming was accompanied by increased craniocervical angles opt/nsl and cvt/nsl (P = 0.008 and 0.002 respectively); widening of the C3-menton distance (P = 0.003), a rise of the larynx and hyoid in relation to the cranial base (P = 0.012 and < 0.001 respectively) and a decreased sternum-hyoid distance (P = 0.004).
Conclusion
Voice production is accompanied by pitch-related adjustments that are currently being masked by, or mistakenly attributed to, articulatory or postural input, identification of which could improve understanding of mechanisms underlying speech and song.
Journal of Voice: official journal of the Voice Foundation, Jan 2012
Objectives
Traditional voice research focuses upon the vocal tract, articulators and larynx. By ... more Objectives
Traditional voice research focuses upon the vocal tract, articulators and larynx. By ignoring their direct/indirect attachments (skull, cervical spine, sternum) important information may be missed. We aim to investigate vocal structures within this wider context and assess the validity of this approach for subsequent voice production studies.
Study Design / Method
Using a cross-sectional study design we obtained mid-sagittal MR images from ten healthy adults (5 males, 5 females) while at rest and breathing quietly. With reference points based upon cephalometry, 17 craniocervical, craniocaudal and antero-posterior variables were chosen to describe craniofacial morphology, craniocervical posture and airway dimensions. Relationships between variables were sought using Pearson’s correlation coefficient.
Results
We found widespread correlations relating vocal structures to the craniofacial skeleton and cervical spine (r > 0.6). Increasing airway size (hyocervical distance) was associated with greater distances from the cranial base of the hyoid, larynx, epiglottis tip and uvula tip, and of C3 from the menton. A wider velopharyngeal opening was associated with a shorter and higher soft palate, and a greater (lower) craniocervical angle was associated with a wider laryngeal tube opening, narrower airway at the uvula tip and shorter distances of the hyoid and uvula tip from the cranial base.
Conclusion
Finding widespread correlations relating vocal structures to the craniofacial skeleton and cervical spine confirms the potential of this approach to uncover functional activity during voice production and demonstrates the importance of considering vocal structures and the airway within this wider context if important information is not to be missed.
Keywords
MRI-Cephalometry-Vocal Tract-Speech-Posture
Purpose. There is a continuing need to improve the prediction of hip fractures to identify those ... more Purpose. There is a continuing need to improve the prediction of hip fractures to identify those at highest risk, enabling cost-effective use of preventative therapies.
Traditional voice research occurs within a phonetic context. Accordingly, pitch-related contribut... more Traditional voice research occurs within a phonetic context. Accordingly, pitch-related contributions are inseparable from those due to articulator input. In humming, articulator input is negligible. Using MRI we test the hypothesis that voice production is accompanied by pitch-related adjustments unrelated to articulatory or postural input.
The shape of the lumbar spine in the sagittal plane varies between individuals and as a result of... more The shape of the lumbar spine in the sagittal plane varies between individuals and as a result of postural changes but it is not known how the shape in different postures is related. Sagittal images of the lumbar spines of 24 male volunteers were acquired using a positional magnetic resonance scanner. The subjects were imaged lying supine, standing and sitting. An active shape model was used to characterize shape in terms of independent modes of variation. Two modes were identified that described the total (mode 1) and distribution (mode 2) of the curvature. The spinal shape was found to be intercorrelated between the three postures for both modes, suggesting that the lumbar spine has an element of shape that is partially maintained despite postural alterations. Mode 1 values indicated that the spine was straightest when standing and curviest when sitting. Mode 2 values indicated that the distribution in the curvature was most even when sitting and least even when lying supine. Systematic differences in the behaviour of the spine, when changing posture, were found that suggest that the shape of the spine may affect its biomechanics.
Determining the effect of load carriage on the human spine in vivo is important for determining s... more Determining the effect of load carriage on the human spine in vivo is important for determining spinal forces and establishing potential mechanisms of back injury. Previous studies have suggested that the natural curvature of the spine straightens under load, but are based on modelling and external measurements from the surface of the back. In the current study, an upright positional MRI scanner was used to acquire sagittal images of the lumbar and lower thoracic spine of 24 subjects. The subjects were imaged in standing whilst supporting 0, 8 and 16 kg of load which was applied axially across the shoulders using an apron. An active shape model of the vertebral bodies from T10 to S1 was created and used to characterise the effect of load. The results from the shape model showed that the behaviour of the average-shaped spine was to straighten slightly. However, the shape model also showed that the effect of load exhibited systematic variation between individuals. Those who had a smaller than average curvature before loading straightened under load, whereas those who had a greater than average curvature before loading showed an increase in curvature under load. The variation in behaviour of differently shaped spines may have further implications for the effects of load in lifting manoeuvres and in understanding the aetiology of back pain.
Nuclear magnetic resonance is increasingly recognised as a means of assessing attributes of f... more Nuclear magnetic resonance is increasingly recognised as a means of assessing attributes of foodstuffs. Usually this has meant removing samples for testing in laboratories, often some distance from the site of food production, using large and expensive equipment. Here we present some preliminary results demonstrating the use of a small device using single-sided magnets that could, in principle, be made portable. Ripening of fruit, water content in chicken and anisotropic properties of asparagus and tendon are used as examples of measurements that have been made previously using conventional instruments. The results show that data can be obtained rapidly and that the new method of testing could be extended to non-invasive measurements on larger objects.
BMC Medical Imaging , 4:4, 2004
Background
This study presents an analysis of trabecular bone s... more BMC Medical Imaging , 4:4, 2004
Background
This study presents an analysis of trabecular bone structure in standard radiographs using Fourier transforms and principal components analysis (PCA) to identify contributions to hip fracture risk. Methods
Radiographs were obtained from 26 hip fracture patients and 24 controls. They were digitised and five regions of interest (ROI) were identified from the femoral head and neck for analysis. The power spectrum was obtained from the Fourier transform of each region and three profiles were produced; a circular profile and profiles parallel and perpendicular to the preferred orientation of the trabeculae. PCA was used to generate a score from each profile, which we hypothesised could be used to discriminate between the fracture and control groups. The fractal dimension was also calculated for comparison. The area under the receiver operating characteristic curve (Az) discriminating the hip fracture cases from controls was calculated for each analysis. Results
Texture analysis of standard radiographs using the fast Fourier transform yielded variables that were significantly associated with fracture and not significantly correlated with age, body mass index or femoral neck bone mineral density. The anisotropy of the trabecular structure was important; both the perpendicular and circular profiles were significantly better than the parallel-profile (P < 0.05). No significant differences resulted from using the various ROI within the proximal femur. For the best three groupings of profile (circular, parallel or perpendicular), method (PCA or fractal) and ROI (Az = 0.84 – 0.93), there were no significant correlations with femoral neck bone mineral density, age, or body mass index. PCA analysis was found to perform better than fractal analysis (P = 0.019). Conclusions
Both PCA and fractal analysis of the FFT data could discriminate successfully between the fracture and control groups, although PCA was significantly stronger than fractal dimension. This method appears to provide a powerful tool for the assessment of bone structure in vivo with advantages over standard fractal methods.
Hip fracture due to osteoporosis (OP) and hip osteoarthritis (OA) are both important causes of lo... more Hip fracture due to osteoporosis (OP) and hip osteoarthritis (OA) are both important causes of locomotor morbidity in the elderly population. In osteoporosis, bone mass gradually decreases until the skeleton is too fragile to support the body and a fracture occurs, typically in the femur, wrist, or spine. In osteoarthritis, there is a proliferation of bone, leading to a stiffening of the tissue. Current clinical methods for assessment of bone changes in these disorders largely depend on assessing bone mineral density. However, this does not provide any information about bone structure which is considered to be an equally important factor in assessing bone quality. This paper presents a novel approach for computer analysis of trabecular (or cancellous) bone structure. The technique uses a Fourier transform to generate a "spectral fingerprint" of an image. Principal components analysis is then applied to identify key features from the Fourier transform and this information passed to a neural network for classification. Testing this on a series of 100 histological sections of trabecular bone from patients with OP and OA and a normal group correctly classified over 90% of the OP group with an overall accuracy of 77%-84%. Such high success rates on a small group suggest that this may provide a simple, but powerful, method for identifying alterations in bone structure.
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Papers by Jenny Gregory
The shape of the vocal tract and associated structures (e.g. tongue and velum) is complicated and varies according to development and function. This variability challenges interpretation of voice experiments. Quantifying differences between shapes and understanding how vocal structures move in relation to each other is difficult using traditional linear and angle measurements. With statistical shape models, shape can be characterized in terms of independent modes of variation. Here, we build an active shape model (ASM) to assess morphological and pitch-related functional changes affecting vocal structures and the airway.
Method
Using a cross-sectional study design, we obtained 6 midsagittal MR images from 10 healthy adults (5 males and five females) at rest, while breathing out, and while listening to and humming low and high notes. Eighty landmark points were chosen to define the shape of interest and an ASM was built using these (60) images. Principal component analysis was used to identify independent modes of variation and statistical analysis was performed using one-way repeated-measures ANOVA.
Results
Twenty modes of variation were identified with modes 1 and 2 accounting for half the total variance. Modes 1 and 9 were significantly associated with humming low and high notes (P < 0.001) and showed coordinated changes affecting the cervical spine, vocal structures and airway. Mode 2 highlighted wide structural variations between subjects.
Conclusion
This study highlights the potential of active shape modelling to advance understanding of factors underlying morphological and pitch-related functional variations affecting vocal structures and the airway in health and disease.
Traditional voice research occurs within a phonetic context. Accordingly, pitch-related contributions are inseparable from those due to articulator input. In humming, articulator input is negligible. Using MRI we test the hypothesis that voice production is accompanied by pitch-related adjustments unrelated to articulatory or postural input.
Study Design / Method
In this cross-sectional study, 10 healthy volunteers (5 males, 5 females, age 20-47, median 25 years) including singers (6 months-10 years tuition, median 2 years) and non-singers, were assessed to establish the lowest and highest notes they could comfortably sustain while humming over 20 seconds. With head position stable, mid-sagittal images were acquired while volunteers hummed these predetermined low and high notes. 22 craniocervical, angular and linear dimensions defined on these images were compared using One Way Repeated Measures ANOVA. Correlations between variables were sought using Pearson’s correlation coefficient.
Results
We found significant differences between low and high note conditions in 6/22 measures and widespread pitch-related correlations between variables (r ≥ 0.66, P < 0.05). Compared with low note humming, high note humming was accompanied by increased craniocervical angles opt/nsl and cvt/nsl (P = 0.008 and 0.002 respectively); widening of the C3-menton distance (P = 0.003), a rise of the larynx and hyoid in relation to the cranial base (P = 0.012 and < 0.001 respectively) and a decreased sternum-hyoid distance (P = 0.004).
Conclusion
Voice production is accompanied by pitch-related adjustments that are currently being masked by, or mistakenly attributed to, articulatory or postural input, identification of which could improve understanding of mechanisms underlying speech and song.
Traditional voice research focuses upon the vocal tract, articulators and larynx. By ignoring their direct/indirect attachments (skull, cervical spine, sternum) important information may be missed. We aim to investigate vocal structures within this wider context and assess the validity of this approach for subsequent voice production studies.
Study Design / Method
Using a cross-sectional study design we obtained mid-sagittal MR images from ten healthy adults (5 males, 5 females) while at rest and breathing quietly. With reference points based upon cephalometry, 17 craniocervical, craniocaudal and antero-posterior variables were chosen to describe craniofacial morphology, craniocervical posture and airway dimensions. Relationships between variables were sought using Pearson’s correlation coefficient.
Results
We found widespread correlations relating vocal structures to the craniofacial skeleton and cervical spine (r > 0.6). Increasing airway size (hyocervical distance) was associated with greater distances from the cranial base of the hyoid, larynx, epiglottis tip and uvula tip, and of C3 from the menton. A wider velopharyngeal opening was associated with a shorter and higher soft palate, and a greater (lower) craniocervical angle was associated with a wider laryngeal tube opening, narrower airway at the uvula tip and shorter distances of the hyoid and uvula tip from the cranial base.
Conclusion
Finding widespread correlations relating vocal structures to the craniofacial skeleton and cervical spine confirms the potential of this approach to uncover functional activity during voice production and demonstrates the importance of considering vocal structures and the airway within this wider context if important information is not to be missed.
Keywords
MRI-Cephalometry-Vocal Tract-Speech-Posture
***Highlighted by Faculty of 1000 ***
http://facultyof1000.com/
Background
This study presents an analysis of trabecular bone structure in standard radiographs using Fourier transforms and principal components analysis (PCA) to identify contributions to hip fracture risk.
Methods
Radiographs were obtained from 26 hip fracture patients and 24 controls. They were digitised and five regions of interest (ROI) were identified from the femoral head and neck for analysis. The power spectrum was obtained from the Fourier transform of each region and three profiles were produced; a circular profile and profiles parallel and perpendicular to the preferred orientation of the trabeculae. PCA was used to generate a score from each profile, which we hypothesised could be used to discriminate between the fracture and control groups. The fractal dimension was also calculated for comparison. The area under the receiver operating characteristic curve (Az) discriminating the hip fracture cases from controls was calculated for each analysis.
Results
Texture analysis of standard radiographs using the fast Fourier transform yielded variables that were significantly associated with fracture and not significantly correlated with age, body mass index or femoral neck bone mineral density. The anisotropy of the trabecular structure was important; both the perpendicular and circular profiles were significantly better than the parallel-profile (P < 0.05). No significant differences resulted from using the various ROI within the proximal femur. For the best three groupings of profile (circular, parallel or perpendicular), method (PCA or fractal) and ROI (Az = 0.84 – 0.93), there were no significant correlations with femoral neck bone mineral density, age, or body mass index. PCA analysis was found to perform better than fractal analysis (P = 0.019).
Conclusions
Both PCA and fractal analysis of the FFT data could discriminate successfully between the fracture and control groups, although PCA was significantly stronger than fractal dimension. This method appears to provide a powerful tool for the assessment of bone structure in vivo with advantages over standard fractal methods.
The shape of the vocal tract and associated structures (e.g. tongue and velum) is complicated and varies according to development and function. This variability challenges interpretation of voice experiments. Quantifying differences between shapes and understanding how vocal structures move in relation to each other is difficult using traditional linear and angle measurements. With statistical shape models, shape can be characterized in terms of independent modes of variation. Here, we build an active shape model (ASM) to assess morphological and pitch-related functional changes affecting vocal structures and the airway.
Method
Using a cross-sectional study design, we obtained 6 midsagittal MR images from 10 healthy adults (5 males and five females) at rest, while breathing out, and while listening to and humming low and high notes. Eighty landmark points were chosen to define the shape of interest and an ASM was built using these (60) images. Principal component analysis was used to identify independent modes of variation and statistical analysis was performed using one-way repeated-measures ANOVA.
Results
Twenty modes of variation were identified with modes 1 and 2 accounting for half the total variance. Modes 1 and 9 were significantly associated with humming low and high notes (P < 0.001) and showed coordinated changes affecting the cervical spine, vocal structures and airway. Mode 2 highlighted wide structural variations between subjects.
Conclusion
This study highlights the potential of active shape modelling to advance understanding of factors underlying morphological and pitch-related functional variations affecting vocal structures and the airway in health and disease.
Traditional voice research occurs within a phonetic context. Accordingly, pitch-related contributions are inseparable from those due to articulator input. In humming, articulator input is negligible. Using MRI we test the hypothesis that voice production is accompanied by pitch-related adjustments unrelated to articulatory or postural input.
Study Design / Method
In this cross-sectional study, 10 healthy volunteers (5 males, 5 females, age 20-47, median 25 years) including singers (6 months-10 years tuition, median 2 years) and non-singers, were assessed to establish the lowest and highest notes they could comfortably sustain while humming over 20 seconds. With head position stable, mid-sagittal images were acquired while volunteers hummed these predetermined low and high notes. 22 craniocervical, angular and linear dimensions defined on these images were compared using One Way Repeated Measures ANOVA. Correlations between variables were sought using Pearson’s correlation coefficient.
Results
We found significant differences between low and high note conditions in 6/22 measures and widespread pitch-related correlations between variables (r ≥ 0.66, P < 0.05). Compared with low note humming, high note humming was accompanied by increased craniocervical angles opt/nsl and cvt/nsl (P = 0.008 and 0.002 respectively); widening of the C3-menton distance (P = 0.003), a rise of the larynx and hyoid in relation to the cranial base (P = 0.012 and < 0.001 respectively) and a decreased sternum-hyoid distance (P = 0.004).
Conclusion
Voice production is accompanied by pitch-related adjustments that are currently being masked by, or mistakenly attributed to, articulatory or postural input, identification of which could improve understanding of mechanisms underlying speech and song.
Traditional voice research focuses upon the vocal tract, articulators and larynx. By ignoring their direct/indirect attachments (skull, cervical spine, sternum) important information may be missed. We aim to investigate vocal structures within this wider context and assess the validity of this approach for subsequent voice production studies.
Study Design / Method
Using a cross-sectional study design we obtained mid-sagittal MR images from ten healthy adults (5 males, 5 females) while at rest and breathing quietly. With reference points based upon cephalometry, 17 craniocervical, craniocaudal and antero-posterior variables were chosen to describe craniofacial morphology, craniocervical posture and airway dimensions. Relationships between variables were sought using Pearson’s correlation coefficient.
Results
We found widespread correlations relating vocal structures to the craniofacial skeleton and cervical spine (r > 0.6). Increasing airway size (hyocervical distance) was associated with greater distances from the cranial base of the hyoid, larynx, epiglottis tip and uvula tip, and of C3 from the menton. A wider velopharyngeal opening was associated with a shorter and higher soft palate, and a greater (lower) craniocervical angle was associated with a wider laryngeal tube opening, narrower airway at the uvula tip and shorter distances of the hyoid and uvula tip from the cranial base.
Conclusion
Finding widespread correlations relating vocal structures to the craniofacial skeleton and cervical spine confirms the potential of this approach to uncover functional activity during voice production and demonstrates the importance of considering vocal structures and the airway within this wider context if important information is not to be missed.
Keywords
MRI-Cephalometry-Vocal Tract-Speech-Posture
***Highlighted by Faculty of 1000 ***
http://facultyof1000.com/
Background
This study presents an analysis of trabecular bone structure in standard radiographs using Fourier transforms and principal components analysis (PCA) to identify contributions to hip fracture risk.
Methods
Radiographs were obtained from 26 hip fracture patients and 24 controls. They were digitised and five regions of interest (ROI) were identified from the femoral head and neck for analysis. The power spectrum was obtained from the Fourier transform of each region and three profiles were produced; a circular profile and profiles parallel and perpendicular to the preferred orientation of the trabeculae. PCA was used to generate a score from each profile, which we hypothesised could be used to discriminate between the fracture and control groups. The fractal dimension was also calculated for comparison. The area under the receiver operating characteristic curve (Az) discriminating the hip fracture cases from controls was calculated for each analysis.
Results
Texture analysis of standard radiographs using the fast Fourier transform yielded variables that were significantly associated with fracture and not significantly correlated with age, body mass index or femoral neck bone mineral density. The anisotropy of the trabecular structure was important; both the perpendicular and circular profiles were significantly better than the parallel-profile (P < 0.05). No significant differences resulted from using the various ROI within the proximal femur. For the best three groupings of profile (circular, parallel or perpendicular), method (PCA or fractal) and ROI (Az = 0.84 – 0.93), there were no significant correlations with femoral neck bone mineral density, age, or body mass index. PCA analysis was found to perform better than fractal analysis (P = 0.019).
Conclusions
Both PCA and fractal analysis of the FFT data could discriminate successfully between the fracture and control groups, although PCA was significantly stronger than fractal dimension. This method appears to provide a powerful tool for the assessment of bone structure in vivo with advantages over standard fractal methods.