scholarly journals Advances in real-time magnetic resonance imaging of the vocal tract for speech science and technology research

Author(s):  
Asterios Toutios ◽  
Shrikanth S. Narayanan

Real-time magnetic resonance imaging (rtMRI) of the moving vocal tract during running speech production is an important emerging tool for speech production research providing dynamic information of a speaker's upper airway from the entire midsagittal plane or any other scan plane of interest. There have been several advances in the development of speech rtMRI and corresponding analysis tools, and their application to domains such as phonetics and phonological theory, articulatory modeling, and speaker characterization. An important recent development has been the open release of a database that includes speech rtMRI data from five male and five female speakers of American English each producing 460 phonetically balanced sentences. The purpose of the present paper is to give an overview and outlook of the advances in rtMRI as a tool for speech research and technology development.

2017 ◽  
Vol 45 (3) ◽  
Author(s):  
Christian Bamberg ◽  
Jan Deprest ◽  
Nikhil Sindhwani ◽  
Ulf Teichgräberg ◽  
Felix Güttler ◽  
...  

AbstractAim:Fetal skull molding is important for the adaptation of the head to the birth canal during vaginal delivery. Importantly, the fetal head must rotate around the maternal symphysis pubis. The goals of this analysis were to observe a human birth in real-time using an open magnetic resonance imaging (MRI) scanner and describe the fetal head configuration during expulsion.Methods:Real-time cinematic MRI series (TSE single-shot sequence, TR 1600 ms, TE 150 ms) were acquired from the midsagittal plane of the maternal pelvis during the active second stage of labor at 37 weeks of gestation. Frame-by-frame analyses were performed to measure the frontooccipital diameter (FOD) and distance from the vertex to the base of the fetal skull.Results:During vaginal delivery in an occiput anterior position, the initial FOD was 10.3 cm. When expulsion began, the fetal skull was deformed and elongated, with the FOD increasing to 10.8 cm and 11.2 cm at crowning. In contrast, the distance from the vertex to the base of the skull was reduced from 6.4 cm to 5.6 cm at expulsion.Conclusions:Fetal head molding is the change in the fetal head due to the forces of labor. The biomechanics of this process are poorly understood. Our visualization of the normal mechanism of late second-stage labor shows that MRI technology can for the first time help define the changes in the diameters of the fetal head during active labor.


2014 ◽  
Vol 136 (3) ◽  
pp. 1307-1311 ◽  
Author(s):  
Shrikanth Narayanan ◽  
Asterios Toutios ◽  
Vikram Ramanarayanan ◽  
Adam Lammert ◽  
Jangwon Kim ◽  
...  

2017 ◽  
Vol 60 (4) ◽  
pp. 877-891 ◽  
Author(s):  
Christina Hagedorn ◽  
Michael Proctor ◽  
Louis Goldstein ◽  
Stephen M. Wilson ◽  
Bruce Miller ◽  
...  

Purpose Real-time magnetic resonance imaging (MRI) and accompanying analytical methods are shown to capture and quantify salient aspects of apraxic speech, substantiating and expanding upon evidence provided by clinical observation and acoustic and kinematic data. Analysis of apraxic speech errors within a dynamic systems framework is provided and the nature of pathomechanisms of apraxic speech discussed. Method One adult male speaker with apraxia of speech was imaged using real-time MRI while producing spontaneous speech, repeated naming tasks, and self-paced repetition of word pairs designed to elicit speech errors. Articulatory data were analyzed, and speech errors were detected using time series reflecting articulatory activity in regions of interest. Results Real-time MRI captured two types of apraxic gestural intrusion errors in a word pair repetition task. Gestural intrusion errors in nonrepetitive speech, multiple silent initiation gestures at the onset of speech, and covert (unphonated) articulation of entire monosyllabic words were also captured. Conclusion Real-time MRI and accompanying analytical methods capture and quantify many features of apraxic speech that have been previously observed using other modalities while offering high spatial resolution. This patient's apraxia of speech affected the ability to select only the appropriate vocal tract gestures for a target utterance, suppressing others, and to coordinate them in time.


2003 ◽  
Vol 113 (4) ◽  
pp. 2258-2258
Author(s):  
Shrikanth Narayanan ◽  
Krishna Nayak ◽  
Dani Byrd ◽  
Sungbok Lee

2004 ◽  
Vol 115 (4) ◽  
pp. 1771-1776 ◽  
Author(s):  
Shrikanth Narayanan ◽  
Krishna Nayak ◽  
Sungbok Lee ◽  
Abhinav Sethy ◽  
Dani Byrd

Sign in / Sign up

Export Citation Format

Share Document