Electromagnetic Articulography (EMA) was used to provide augmented visual feedback in the learnin... more Electromagnetic Articulography (EMA) was used to provide augmented visual feedback in the learning of non-native speech sounds. Eight adult native speakers of English were randomly assigned to one of the two training conditions: (1) conventional L2 speech production training or (2) conventional L2 speech production training with EMA-based kinematic feedback. The participants' speech was perceptually judged by six native speakers of Japanese. The results indicate that kinematic feedback with EMA facilitates the acquisition and maintenance of the Japanese flap consonant, providing superior acquisition and maintenance. The findings suggest augmented visual feedback may play an important role in adults' L2 learning.
Folia phoniatrica et logopaedica : official organ of the International Association of Logopedics and Phoniatrics (IALP), 2010
Apraxia of speech (AOS) is a motor speech disorder characterized by disturbed spatial and tempora... more Apraxia of speech (AOS) is a motor speech disorder characterized by disturbed spatial and temporal parameters of movement. Research on motor learning suggests that augmented feedback may provide a beneficial effect for training movement. This study examined the effects of the presence and frequency of online augmented visual kinematic feedback (AVKF) and clinician-provided perceptual feedback on speech accuracy in 2 adults with acquired AOS. Within a single-subject multiple-baseline design, AVKF was provided using electromagnetic midsagittal articulography (EMA) in 2 feedback conditions (50 or 100%). Articulator placement was specified for speech motor targets (SMTs). Treated and baselined SMTs were in the initial or final position of single-syllable words, in varying consonant-vowel or vowel-consonant contexts. SMTs were selected based on each participant's pre-assessed erred productions. Productions were digitally recorded and online perceptual judgments of accuracy (including...
Perspectives on Neurophysiology and Neurogenic Speech and Language Disorders, 2010
... Paper presented at the International Conference on Speech Motor Control, Austin, TX.Schönle, ... more ... Paper presented at the International Conference on Speech Motor Control, Austin, TX.Schönle, P., Grabe, K., Wenig, P., Hohne, J., Schrader, J., & Conrad, B. (1987). ... Wambaugh, J., Duffy, J., McNeil, M., Robin, D., & Rogers, M. (2006). ...
Three experiments examined whether the Clarion 1.2 S-Series cochlear implant could be safely and ... more Three experiments examined whether the Clarion 1.2 S-Series cochlear implant could be safely and effectively used within a Carstens Medizinelektronik EMA (electromagnetic articulography) system. Experiment 1 indicated no measurable effects of EMA magnetic fields on implant function. Experiment 2 showed no influence of the implant on the accuracy of EMA measurements. Experiment 3 found no indication of reduced sentence repetition abilities when EMA fields were present. The results suggest experiments with the Clarion 1.2 cochlear implant and the Carstens AG100 articulograph are safe and feasible.
Foreign accent syndrome (FAS) is a rare disorder characterized by the emergence of a perceived fo... more Foreign accent syndrome (FAS) is a rare disorder characterized by the emergence of a perceived foreign accent following brain damage. Despite decades of study, little is known about the neural substrates involved in this disorder. In this case study, MRI images of the brain were obtained during a speech task for an American English-speaking monolingual female who presented with FAS of unknown etiology and was thought to sound "Swedish" or "Eastern European." On the basis of MR structural imaging, the patient was noted to have frontal lobe
The Journal of the Acoustical Society of America, 2006
Acoustic analyses and perception experiments were conducted to determine the effects of brief dep... more Acoustic analyses and perception experiments were conducted to determine the effects of brief deprivation of auditory feedback on fricatives produced by cochlear implant users. The words /si/ and /Si/ were recorded by four children and four adults with their cochlear implant speech processor turned on or off. In the processor-off condition, word durations increased significantly for a majority of talkers. These increases were greater for children compared to adults, suggesting that children may rely on auditory feedback to a greater extent than adults. Significant differences in spectral measures of /S/ were found between processor-on and processor-off conditions for two of the four children and for one of the four adults. These talkers also demonstrated a larger /s/-/S/ contrast in centroid values compared to the other talkers within their respective groups. This finding may indicate that talkers who produce fine spectral distinctions are able to perceive these distinctions through their implants and to use this feedback to fine tune their speech. Two listening experiments provided evidence that some of the acoustic changes were perceptible to normal-hearing listeners. Taken together, these experiments indicate that for certain cochlear-implant users the brief absence of auditory feedback may lead to perceptible modifications in fricative consonants.
The Journal of the Acoustical Society of America, 2005
Recent studies have shown that synthesized versions of American English vowels are less accuratel... more Recent studies have shown that synthesized versions of American English vowels are less accurately identified when the natural time-varying spectral changes are eliminated by holding the formant frequencies constant over the duration of the vowel. A limitation of these experiments has been that vowels produced by formant synthesis are generally less accurately identified than the natural vowels after which they are modeled. To overcome this limitation, a high-quality speech analysis-synthesis system (STRAIGHT) was used to synthesize versions of 12 American English vowels spoken by adults and children. Vowels synthesized with STRAIGHT were identified as accurately as the natural versions, in contrast with previous results from our laboratory showing identification rates 9%-12% lower for the same vowels synthesized using the cascade formant model. Consistent with earlier studies, identification accuracy was not reduced when the fundamental frequency was held constant across the vowel. However, elimination of time-varying changes in the spectral envelope using STRAIGHT led to a greater reduction in accuracy (23%) than was previously found with cascade formant synthesis (11%). A statistical pattern recognition model, applied to acoustic measurements of the natural and synthesized vowels, predicted both the higher identification accuracy for vowels synthesized using STRAIGHT compared to formant synthesis, and the greater effects of holding the formant frequencies constant over time with STRAIGHT synthesis. Taken together, the experiment and modeling results suggest that formant estimation errors and incorrect rendering of spectral and temporal cues by cascade formant synthesis contribute to lower identification accuracy and underestimation of the role of time-varying spectral change in vowels.
The Journal of the Acoustical Society of America, 2002
A prominent theory of speech production proposes that speech segments are largely controlled by r... more A prominent theory of speech production proposes that speech segments are largely controlled by reference to an internal model, with minimal reliance on auditory feedback. This theory also maintains that suprasegmental aspects of speech are directly regulated by auditory ...
The Journal of the Acoustical Society of America, 1995
Identification of natural and synthesized vowels produced by children and adults: Effects of form... more Identification of natural and synthesized vowels produced by children and adults: Effects of formant frequency variation. [The Journal of the Acoustical Society of America 98, 2964 (1995)]. Peter F. Assmann, William F. Katz, Kathleen M. Jenouri, Phillip W. Hamilton. Abstract. ...
The Journal of the Acoustical Society of America, 2000
Two competing theories attempt to explain anticipatory coarticulation in the speech of adults and... more Two competing theories attempt to explain anticipatory coarticulation in the speech of adults and children: One suggests more extensive coarticulation in children's speech than in that of adults, while the other suggests more extensive coarticulation in adult speech [see S. ...
The Journal of the Acoustical Society of America, 2007
ABSTRACT Foreign accent syndrome (FAS) is an unusual motor speech disorder involving a perceived ... more ABSTRACT Foreign accent syndrome (FAS) is an unusual motor speech disorder involving a perceived foreign accent resulting from brain damage. An important question concerning FAS is the role of prosodic deficits, including the extent to which difficulties in stress assignment may contribute to segmental errors. In this study, acoustic analyses were performed on the speech of a 46‐year‐old female patient who presented with a pseudo‐accent described as Swedish. Stop consonant VOT, consonant burst spectra and duration, and vowelformant frequencies and trajectories were analyzed, along with prosodic cues for lexical stress assignment and sentence‐level intonation. Results indicated that the patients vowels were centralized and realized with reduced dynamic specifications. There was a strong tendency to realize the English alveolar flap as a full stop, and to produce flaps that had greater‐than‐normal closure durations. Lexical stress assignment was frequently inaccurate and highly variable, with similar problems noted for non‐speech stimuli. Overall, the data suggest that stress assignment deficits were the basis for most of her segmental difficulties. The findings support the view that local prosodic deficits play a critical role in FAS.
Journal of Speech, Language, and Hearing Research, 2009
Electromagnetic articulography (EMA) uses a helmet to create alternating magnetic fields for trac... more Electromagnetic articulography (EMA) uses a helmet to create alternating magnetic fields for tracking speech articulator movement. An important safety consideration is whether EMA magnetic fields interfere with the operation of speakers' pacemakers or implantable cardioverter-defibrillators (ICDs). In this investigation, individuals with pacemaker/ICD devices were exposed to EMA fields under controlled conditions while potential interference was examined. Twelve adults with pacemaker/ICD devices from 3 major manufacturers were assessed for device function before, during, and after exposure to magnetic fields from a Carstens AG100 EMA system. Potential interference was probed, with EMA transmitters positioned at varying distances from the implantable devices and with the EMA system set at different operating strengths. No adverse affects in device operation were observed under any conditions. The only potential complication was temporary telemetry-link interference during device testing in some cases. The results suggest that EMA technology may be safely used with patients who have pacemakers and ICDs. However, the present findings do not rule out potential interference with other pacemaker/ICD manufacturers or with different articulography systems. Precautions are suggested for testing individuals with pacemaker/ICDs under EMA conditions.
Journal of Speech, Language, and Hearing Research, 2006
This study examined whether the intraoral transducers used in electromagnetic articulography (EMA... more This study examined whether the intraoral transducers used in electromagnetic articulography (EMA) interfere with speech and whether there is an added risk of interference when EMA systems are used to study individuals with aphasia and apraxia. Ten adult talkers (5 individuals with aphasia/apraxia, 5 controls) produced 12 American English vowels in /hVd/ words, the fricative-vowel (FV) words (/si/, /su/, /ei/, /eu/), and the sentence She had your dark suit in greasy wash water all year, in EMA sensors-on and sensors-off conditions. Segmental durations, vowel formant frequencies, and fricative spectral moments were measured to address possible acoustic effects of sensor placement. A perceptual experiment examined whether FV words produced in the sensors-on condition were less identifiable than those produced in the sensors-off condition. EMA sensors caused no consistent acoustic effects across all talkers, although significant within-subject effects were noted for a small subset of the talkers. The perceptual results revealed some instances of sensor-related intelligibility loss for FV words produced by individuals with aphasia and apraxia. The findings support previous suggestions that acoustic screening procedures be used to protect articulatory experiments from those individuals who may show consistent effects of having devices placed on intraoral structures. The findings further suggest that studies of fricatives produced by individuals with aphasia and apraxia may require additional safeguards to ensure that results are not adversely affected by intraoral sensor interference.
... 23. J. Hillenbrand, LA Getty, MJ Clark and K. Wheeler, Acoustic characteristics of American E... more ... 23. J. Hillenbrand, LA Getty, MJ Clark and K. Wheeler, Acoustic characteristics of American English vowels. Journal of the Acoustical Society of America 97 (1995), pp. 3099–3111. ... 35. P. Ladefoged and D. Broadbent, Information conveyed by vowels. ...
Positron emission tomography (PET) was used to investigate the functional anatomy of auditory and... more Positron emission tomography (PET) was used to investigate the functional anatomy of auditory and phonological processing. Stimulus sets were designed to determine areas of the brain significantly activated during speech and nonspeech acoustic processing for stimuli with or without rapidly changing acoustic cues. Performance of auditory target detection tasks using these stimulus sets produced increased activation in superior temporal, frontal opercular, and medial frontal (SMA) cortices, relative to a visual fixation control task. While the medial frontal and superior temporal changes are best explained by motor and sensory components of the task, respectively, the frontal opercular changes were dependent upon the task performed upon the auditory input (mere presentation of the stimuli did not result in significant activation). On the left, the frontal opercular increases were larger when subjects performed an auditory detection task upon stimuli that incorporated rapid temporal changes (words, syllables, and tone sequences) than steady-state vowels. A converging study involving performance of orthographic (ascending letter) and phonological (long vowel sound) word discrimination tasks supports anatomical and behavioral evidence suggesting the left frontal opercular region is important for certain types of auditory/temporal analysis, as well as high-level articulatory coding. In addition to the activation increases associated with performance of auditory target detection tasks, decreases in activation were observed bilaterally along the intraparietal sulcus and superior parietal cortex, in the Rolandic sulcus, and the posterior cingulate; these decreases may reflect an attentional shift away from areas involved in the fixation task during the performance of a difficult auditory task. These results demonstrate that focusing more closely on basic neural processing differences (such as temporal integration rates) may lead to a better understanding of the specific neural processes that underlie complex phonological tasks.
suggests that individuals with PD have problems processing proprioceptive feedback for movement. ... more suggests that individuals with PD have problems processing proprioceptive feedback for movement. If so, it may be hypothesized that these individuals are unable to appropriately produce articulatory adjustments in the presence of vocal tract perturbation. To examine this hypothesis, a bite block paradigm was used to investigate compensatory articulation in 10 subjects with PD and 10 healthy adult talkers. Problems with on-line sensory feedback during vowel production were indexed by estimating formant frequencies at the vowel midpoint; deficits affecting motor equivalence were addressed by measuring vowel formant frequencies at the onset of each production.
Electromagnetic Articulography (EMA) was used to provide augmented visual feedback in the learnin... more Electromagnetic Articulography (EMA) was used to provide augmented visual feedback in the learning of non-native speech sounds. Eight adult native speakers of English were randomly assigned to one of the two training conditions: (1) conventional L2 speech production training or (2) conventional L2 speech production training with EMA-based kinematic feedback. The participants' speech was perceptually judged by six native speakers of Japanese. The results indicate that kinematic feedback with EMA facilitates the acquisition and maintenance of the Japanese flap consonant, providing superior acquisition and maintenance. The findings suggest augmented visual feedback may play an important role in adults' L2 learning.
Folia phoniatrica et logopaedica : official organ of the International Association of Logopedics and Phoniatrics (IALP), 2010
Apraxia of speech (AOS) is a motor speech disorder characterized by disturbed spatial and tempora... more Apraxia of speech (AOS) is a motor speech disorder characterized by disturbed spatial and temporal parameters of movement. Research on motor learning suggests that augmented feedback may provide a beneficial effect for training movement. This study examined the effects of the presence and frequency of online augmented visual kinematic feedback (AVKF) and clinician-provided perceptual feedback on speech accuracy in 2 adults with acquired AOS. Within a single-subject multiple-baseline design, AVKF was provided using electromagnetic midsagittal articulography (EMA) in 2 feedback conditions (50 or 100%). Articulator placement was specified for speech motor targets (SMTs). Treated and baselined SMTs were in the initial or final position of single-syllable words, in varying consonant-vowel or vowel-consonant contexts. SMTs were selected based on each participant's pre-assessed erred productions. Productions were digitally recorded and online perceptual judgments of accuracy (including...
Perspectives on Neurophysiology and Neurogenic Speech and Language Disorders, 2010
... Paper presented at the International Conference on Speech Motor Control, Austin, TX.Schönle, ... more ... Paper presented at the International Conference on Speech Motor Control, Austin, TX.Schönle, P., Grabe, K., Wenig, P., Hohne, J., Schrader, J., & Conrad, B. (1987). ... Wambaugh, J., Duffy, J., McNeil, M., Robin, D., & Rogers, M. (2006). ...
Three experiments examined whether the Clarion 1.2 S-Series cochlear implant could be safely and ... more Three experiments examined whether the Clarion 1.2 S-Series cochlear implant could be safely and effectively used within a Carstens Medizinelektronik EMA (electromagnetic articulography) system. Experiment 1 indicated no measurable effects of EMA magnetic fields on implant function. Experiment 2 showed no influence of the implant on the accuracy of EMA measurements. Experiment 3 found no indication of reduced sentence repetition abilities when EMA fields were present. The results suggest experiments with the Clarion 1.2 cochlear implant and the Carstens AG100 articulograph are safe and feasible.
Foreign accent syndrome (FAS) is a rare disorder characterized by the emergence of a perceived fo... more Foreign accent syndrome (FAS) is a rare disorder characterized by the emergence of a perceived foreign accent following brain damage. Despite decades of study, little is known about the neural substrates involved in this disorder. In this case study, MRI images of the brain were obtained during a speech task for an American English-speaking monolingual female who presented with FAS of unknown etiology and was thought to sound "Swedish" or "Eastern European." On the basis of MR structural imaging, the patient was noted to have frontal lobe
The Journal of the Acoustical Society of America, 2006
Acoustic analyses and perception experiments were conducted to determine the effects of brief dep... more Acoustic analyses and perception experiments were conducted to determine the effects of brief deprivation of auditory feedback on fricatives produced by cochlear implant users. The words /si/ and /Si/ were recorded by four children and four adults with their cochlear implant speech processor turned on or off. In the processor-off condition, word durations increased significantly for a majority of talkers. These increases were greater for children compared to adults, suggesting that children may rely on auditory feedback to a greater extent than adults. Significant differences in spectral measures of /S/ were found between processor-on and processor-off conditions for two of the four children and for one of the four adults. These talkers also demonstrated a larger /s/-/S/ contrast in centroid values compared to the other talkers within their respective groups. This finding may indicate that talkers who produce fine spectral distinctions are able to perceive these distinctions through their implants and to use this feedback to fine tune their speech. Two listening experiments provided evidence that some of the acoustic changes were perceptible to normal-hearing listeners. Taken together, these experiments indicate that for certain cochlear-implant users the brief absence of auditory feedback may lead to perceptible modifications in fricative consonants.
The Journal of the Acoustical Society of America, 2005
Recent studies have shown that synthesized versions of American English vowels are less accuratel... more Recent studies have shown that synthesized versions of American English vowels are less accurately identified when the natural time-varying spectral changes are eliminated by holding the formant frequencies constant over the duration of the vowel. A limitation of these experiments has been that vowels produced by formant synthesis are generally less accurately identified than the natural vowels after which they are modeled. To overcome this limitation, a high-quality speech analysis-synthesis system (STRAIGHT) was used to synthesize versions of 12 American English vowels spoken by adults and children. Vowels synthesized with STRAIGHT were identified as accurately as the natural versions, in contrast with previous results from our laboratory showing identification rates 9%-12% lower for the same vowels synthesized using the cascade formant model. Consistent with earlier studies, identification accuracy was not reduced when the fundamental frequency was held constant across the vowel. However, elimination of time-varying changes in the spectral envelope using STRAIGHT led to a greater reduction in accuracy (23%) than was previously found with cascade formant synthesis (11%). A statistical pattern recognition model, applied to acoustic measurements of the natural and synthesized vowels, predicted both the higher identification accuracy for vowels synthesized using STRAIGHT compared to formant synthesis, and the greater effects of holding the formant frequencies constant over time with STRAIGHT synthesis. Taken together, the experiment and modeling results suggest that formant estimation errors and incorrect rendering of spectral and temporal cues by cascade formant synthesis contribute to lower identification accuracy and underestimation of the role of time-varying spectral change in vowels.
The Journal of the Acoustical Society of America, 2002
A prominent theory of speech production proposes that speech segments are largely controlled by r... more A prominent theory of speech production proposes that speech segments are largely controlled by reference to an internal model, with minimal reliance on auditory feedback. This theory also maintains that suprasegmental aspects of speech are directly regulated by auditory ...
The Journal of the Acoustical Society of America, 1995
Identification of natural and synthesized vowels produced by children and adults: Effects of form... more Identification of natural and synthesized vowels produced by children and adults: Effects of formant frequency variation. [The Journal of the Acoustical Society of America 98, 2964 (1995)]. Peter F. Assmann, William F. Katz, Kathleen M. Jenouri, Phillip W. Hamilton. Abstract. ...
The Journal of the Acoustical Society of America, 2000
Two competing theories attempt to explain anticipatory coarticulation in the speech of adults and... more Two competing theories attempt to explain anticipatory coarticulation in the speech of adults and children: One suggests more extensive coarticulation in children's speech than in that of adults, while the other suggests more extensive coarticulation in adult speech [see S. ...
The Journal of the Acoustical Society of America, 2007
ABSTRACT Foreign accent syndrome (FAS) is an unusual motor speech disorder involving a perceived ... more ABSTRACT Foreign accent syndrome (FAS) is an unusual motor speech disorder involving a perceived foreign accent resulting from brain damage. An important question concerning FAS is the role of prosodic deficits, including the extent to which difficulties in stress assignment may contribute to segmental errors. In this study, acoustic analyses were performed on the speech of a 46‐year‐old female patient who presented with a pseudo‐accent described as Swedish. Stop consonant VOT, consonant burst spectra and duration, and vowelformant frequencies and trajectories were analyzed, along with prosodic cues for lexical stress assignment and sentence‐level intonation. Results indicated that the patients vowels were centralized and realized with reduced dynamic specifications. There was a strong tendency to realize the English alveolar flap as a full stop, and to produce flaps that had greater‐than‐normal closure durations. Lexical stress assignment was frequently inaccurate and highly variable, with similar problems noted for non‐speech stimuli. Overall, the data suggest that stress assignment deficits were the basis for most of her segmental difficulties. The findings support the view that local prosodic deficits play a critical role in FAS.
Journal of Speech, Language, and Hearing Research, 2009
Electromagnetic articulography (EMA) uses a helmet to create alternating magnetic fields for trac... more Electromagnetic articulography (EMA) uses a helmet to create alternating magnetic fields for tracking speech articulator movement. An important safety consideration is whether EMA magnetic fields interfere with the operation of speakers' pacemakers or implantable cardioverter-defibrillators (ICDs). In this investigation, individuals with pacemaker/ICD devices were exposed to EMA fields under controlled conditions while potential interference was examined. Twelve adults with pacemaker/ICD devices from 3 major manufacturers were assessed for device function before, during, and after exposure to magnetic fields from a Carstens AG100 EMA system. Potential interference was probed, with EMA transmitters positioned at varying distances from the implantable devices and with the EMA system set at different operating strengths. No adverse affects in device operation were observed under any conditions. The only potential complication was temporary telemetry-link interference during device testing in some cases. The results suggest that EMA technology may be safely used with patients who have pacemakers and ICDs. However, the present findings do not rule out potential interference with other pacemaker/ICD manufacturers or with different articulography systems. Precautions are suggested for testing individuals with pacemaker/ICDs under EMA conditions.
Journal of Speech, Language, and Hearing Research, 2006
This study examined whether the intraoral transducers used in electromagnetic articulography (EMA... more This study examined whether the intraoral transducers used in electromagnetic articulography (EMA) interfere with speech and whether there is an added risk of interference when EMA systems are used to study individuals with aphasia and apraxia. Ten adult talkers (5 individuals with aphasia/apraxia, 5 controls) produced 12 American English vowels in /hVd/ words, the fricative-vowel (FV) words (/si/, /su/, /ei/, /eu/), and the sentence She had your dark suit in greasy wash water all year, in EMA sensors-on and sensors-off conditions. Segmental durations, vowel formant frequencies, and fricative spectral moments were measured to address possible acoustic effects of sensor placement. A perceptual experiment examined whether FV words produced in the sensors-on condition were less identifiable than those produced in the sensors-off condition. EMA sensors caused no consistent acoustic effects across all talkers, although significant within-subject effects were noted for a small subset of the talkers. The perceptual results revealed some instances of sensor-related intelligibility loss for FV words produced by individuals with aphasia and apraxia. The findings support previous suggestions that acoustic screening procedures be used to protect articulatory experiments from those individuals who may show consistent effects of having devices placed on intraoral structures. The findings further suggest that studies of fricatives produced by individuals with aphasia and apraxia may require additional safeguards to ensure that results are not adversely affected by intraoral sensor interference.
... 23. J. Hillenbrand, LA Getty, MJ Clark and K. Wheeler, Acoustic characteristics of American E... more ... 23. J. Hillenbrand, LA Getty, MJ Clark and K. Wheeler, Acoustic characteristics of American English vowels. Journal of the Acoustical Society of America 97 (1995), pp. 3099–3111. ... 35. P. Ladefoged and D. Broadbent, Information conveyed by vowels. ...
Positron emission tomography (PET) was used to investigate the functional anatomy of auditory and... more Positron emission tomography (PET) was used to investigate the functional anatomy of auditory and phonological processing. Stimulus sets were designed to determine areas of the brain significantly activated during speech and nonspeech acoustic processing for stimuli with or without rapidly changing acoustic cues. Performance of auditory target detection tasks using these stimulus sets produced increased activation in superior temporal, frontal opercular, and medial frontal (SMA) cortices, relative to a visual fixation control task. While the medial frontal and superior temporal changes are best explained by motor and sensory components of the task, respectively, the frontal opercular changes were dependent upon the task performed upon the auditory input (mere presentation of the stimuli did not result in significant activation). On the left, the frontal opercular increases were larger when subjects performed an auditory detection task upon stimuli that incorporated rapid temporal changes (words, syllables, and tone sequences) than steady-state vowels. A converging study involving performance of orthographic (ascending letter) and phonological (long vowel sound) word discrimination tasks supports anatomical and behavioral evidence suggesting the left frontal opercular region is important for certain types of auditory/temporal analysis, as well as high-level articulatory coding. In addition to the activation increases associated with performance of auditory target detection tasks, decreases in activation were observed bilaterally along the intraparietal sulcus and superior parietal cortex, in the Rolandic sulcus, and the posterior cingulate; these decreases may reflect an attentional shift away from areas involved in the fixation task during the performance of a difficult auditory task. These results demonstrate that focusing more closely on basic neural processing differences (such as temporal integration rates) may lead to a better understanding of the specific neural processes that underlie complex phonological tasks.
suggests that individuals with PD have problems processing proprioceptive feedback for movement. ... more suggests that individuals with PD have problems processing proprioceptive feedback for movement. If so, it may be hypothesized that these individuals are unable to appropriately produce articulatory adjustments in the presence of vocal tract perturbation. To examine this hypothesis, a bite block paradigm was used to investigate compensatory articulation in 10 subjects with PD and 10 healthy adult talkers. Problems with on-line sensory feedback during vowel production were indexed by estimating formant frequencies at the vowel midpoint; deficits affecting motor equivalence were addressed by measuring vowel formant frequencies at the onset of each production.
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Papers by William Katz