Monthly Archives: December 2010
Neural Correlates of Syntactic Processing in the Nonfluent Variant of Primary Progressive Aphasia
The left posterior inferior frontal cortex (IFC) is important for syntactic processing, and has been shown in many functional imaging studies to be differentially recruited for the processing of syntactically complex sentences relative to simpler ones. In the nonfluent variant of primary progressive aphasia (PPA), degeneration of the posterior IFC is associated with expressive and receptive agrammatism; however, the functional status of this region in nonfluent PPA is not well understood. Our objective was to determine whether the atrophic posterior IFC is differentially recruited for the processing of syntactically complex sentences in nonfluent PPA. Using structural and functional magnetic resonance imaging, we quantified tissue volumes and functional responses to a syntactic comprehension task in eight patients with nonfluent PPA, compared to healthy age-matched controls. In controls, the posterior IFC showed more activity for syntactically complex sentences than simpler ones, as expected. In nonfluent PPA patients, the posterior IFC was atrophic and, unlike controls, showed an equivalent level of functional activity for syntactically complex and simpler sentences. This abnormal pattern of functional activity was specific to the posterior IFC: the mid-superior temporal sulcus, another region modulated by syntactic complexity in controls, showed normal modulation by complexity in patients. A more anterior inferior frontal region was recruited by patients, but did not support successful syntactic processing. We conclude that in nonfluent PPA, the posterior IFC is not only structurally damaged, but also functionally abnormal, suggesting a critical role for this region in the breakdown of syntactic processing in this syndrome.
from the Journal of Neuroscience
Rapid Cortical Plasticity Underlying Novel Word Learning
Humans are unique in developing large lexicons as their communication tool. To achieve this, they are able to learn new words rapidly. However, neural bases of this rapid learning, which may be an expression of a more general cognitive mechanism, are not yet understood. To address this, we exposed our subjects to familiar words and novel spoken stimuli in a short passive perceptual learning session and compared automatic brain responses to these items throughout the learning exposure. Initially, we found enhanced activity for known words, indexing the ignition of their underlying memory traces. However, just after 14 min of learning exposure, the novel items exhibited a significant increase in response magnitude matching in size with that to real words. This activation increase, as we would like to propose, reflects rapid mapping of new word forms onto neural representations. Similar to familiar words, the neural activity subserving rapid learning of new word forms was generated in the left-perisylvian language cortex, especially anterior superior-temporal areas. This first report of a neural correlate of rapid learning suggests that our brain may effectively form new neuronal circuits online as it gets exposed to novel patterns in the sensory input. Understanding such fast learning is key to the neurobiological explanation of the human language faculty and learning mechanisms in general.
from the Journal of Neuroscience
Differential language expertise related to white matter architecture in regions subserving sensory-motor coupling, articulation, and interhemispheric transfer
The technique of diffusion tensor imaging (DTI) has been used to investigate alterations in white matter architecture following long-term training and expertise. Professional simultaneous interpreters (SI) provide an ideal model for the investigation of training-induced plasticity due to the high demands placed on sound to motor mapping mechanisms, which are vital for executing fast interpretations. In line with our hypothesis, we found clusters with decreased fractional anisotropy (FA) in the SI group in brain regions previously shown to support sensory-motor coupling mechanisms and speech articulation (cluster extent family-wise error corrected, P < 0.01). Furthermore, we found an altered white matter architecture indicated by lower FA values in the SI group in the most anterior and posterior parts of the corpus callosum. Our results suggest that language expertise is accompanied by plastic adaptations in regions strongly involved in motor aspects of speech and in interhemispheric information transfer. These results have implications for our understanding of language expertise in relation to white matter adaptations. Hum Brain Mapp, 2010. © 2010 Wiley-Liss, Inc.
from Human Brain Mapping
Finding your voice: A singing lesson from functional imaging
Vocal singing (singing with lyrics) shares features common to music and language but it is not clear to what extent they use the same brain systems, particularly at the higher cortical level, and how this varies with expertise. Twenty-six participants of varying singing ability performed two functional imaging tasks. The first examined covert generative language using orthographic lexical retrieval while the second required covert vocal singing of a well-known song. The neural networks subserving covert vocal singing and language were found to be proximally located, and their extent of cortical overlap varied with singing expertise. Nonexpert singers showed greater engagement of their language network during vocal singing, likely accounting for their less tuneful performance. In contrast, expert singers showed a more unilateral pattern of activation associated with reduced engagement of the right frontal lobe. The findings indicate that singing expertise promotes independence from the language network with decoupling producing more tuneful performance. This means that the age-old singing practice of ‘finding your singing voice’ may be neurologically mediated by changing how strongly singing is coupled to the language system. Hum Brain Mapp, 2010. © 2010 Wiley-Liss, Inc.
from Human Brain Mapping
Actor Vocal Training for the Habilitation of Speech in Adolescent Users of Cochlear Implants
This study examined changes to speech production in adolescents with hearing impairment following a period of actor vocal training. In addition to vocal parameters, the study also investigated changes to psychosocial factors such as confidence, self-esteem, and anxiety. The group were adolescent users of cochlear implants (mean age at commencement of training 15.9 years), with approximately half of the group wearing a hearing aid in the contralateral ear. The mean age of implantation of the group was 7.6 years and the participants displayed a range of speech production abilities. Evaluation of posttraining outcomes was performed via a combination of perceptual and acoustic analyses. Significant posttraining changes to vocal parameters included increased pitch range and variability and decreased speaking rate. From a psychosocial perspective, posttraining stress levels were significantly lowered. This study suggested that actor vocal training may benefit young people with hearing impairment, both in the way in which they use their voices and in the way in which they view themselves.
An Analysis of the Reading Strategies Used by Adult and Student Deaf Readers
The purpose of this study was to identify and examine effective reading strategies used by adult deaf readers compared with student deaf readers. There were a total of 11 participants: 5 deaf adults ranging from 27 to 36 years and 6 deaf students ranging from 16 to 20 years. Assessment methods included interview and think-aloud procedures in which individuals were interrupted 3 times during the reading of a text to answer questions about their internal cognitive processes. It was found that both student and adult groups had highly skilled readers who demonstrated higher level reading strategies and less skilled readers who demonstrated lower level strategies, and only the highest skilled reader demonstrated both breadth and depth of strategies in all three categories: “constructing meaning,” “monitoring and improving comprehension,” and “evaluating comprehension.” The study contributes evidence toward two identified gaps in the existing body of research: (a) the lack of investigation into the reading strategies utilized by deaf readers in text comprehension and (b) the overemphasis of most research on studying less skilled deaf readers while overlooking highly proficient deaf readers.
Enhancing Deaf Students’ Learning from Sign Language and Text: Metacognition, Modality, and the Effectiveness of Content Scaffolding
Four experiments, each building on the results of the previous ones, explored the effects of several manipulations on learning and the accuracy of metacognitive judgments among deaf and hard-of-hearing (DHH) students. Experiment 1 examined learning and metacognitive accuracy from classroom lectures with or without prior scaffolding in the form of a description of main points and concepts. Experiment 2 compared the benefits of scaffolding when material was read versus when it was presented as a lecture signed for DHH students and spoken for hearing students. Experiment 3 compared scaffolding provided in the form of main points versus vocabulary, and Experiment 4 examined effects of material familiarity and a delay between study and test. Results indicated that although all students had a tendency to overestimate their performance, hearing students learned more and were more accurate in their metacognitive judgments than DHH students. Content familiarity improved the accuracy of metacognitive judgments by both DHH and hearing students, but the delay manipulation was effective only for hearing students. Consistent with other recent findings, DHH students learned as much from reading as they did from signed instruction. Differences between DHH and hearing students may indicate the need for explicit instruction for DHH students in academically relevant skills acquired incidentally by hearing students.
Exploring Perspectives on Cochlear Implants and Language Acquisition Within the Deaf Community
Cochlear implants generated intense debate almost immediately following their introduction in the 1980s. Today, with a vast number of deaf individuals with cochlear implants, the debate about the cochlear implant device and mode of communication continues. Q-methodology was used in this study to explore cochlear implants and language acquisition perspectives within the deaf community. Thirty respondents sorted 33 statements, which were collected from professional literature and mainstream media, into a forced-choice, quasi-normal template. A by-person factor analysis of the Q-sorts revealed 5 model viewpoints: (a) American Sign Language advocate, (b) bilingual advocate, (c) cochlear implant advocate, (d) diverse options advocate, and (e) English visually advocate. Even though the results indicate 5 distinct perspectives, the Q-method also revealed similarities among them. The results also show that there seems to be some agreement on using a bilingual approach, although the perspectives seem to disagree on which language should be acquired first.
How Do Deaf Signers of LSQ and Their Teachers Construct the Meaning of a Written Text?
Many studies have investigated why learning to read is so problematic for deaf individuals. However, we still know very little about how to teach reading to signing students. In this article, we report on an exploratory qualitative study of deaf LSQ (Langue des signes québécoise) signers learning to read with two teachers, in an effort to better understand what strategies might be most useful in constructing the meaning of a text. By videotaping reading sessions between each teacher and student, then conducting recall interviews, we found that both students and teachers used a number of strategies to construct meaning. The list of strategies observed was categorized as word attack or global meaning types. Developing readers showed different patterns of strategy use, with more global meaning strategies being used by the more independent reader. We also found that the deaf teacher and hearing teacher had different patterns of strategy use, although both favored global meaning types. Finally, our findings indicate that both teachers adapted their strategy use to the needs of the students, but with a different focus. Namely, the deaf teacher used more global meaning strategies with the weaker reader and less with the more independent reader, whereas the hearing teacher showed the opposite pattern.
Looking for an Explanation for the Low Sign Span. Is Order Involved?
Although signed and speech-based languages have a similar internal organization of verbal short-term memory, sign span is lower than word span. We investigated whether this is due to the fact that signs are not suited for serial recall, as proposed by Bavelier, Newport, Hall, Supalla, and Boutla (2008. Ordered short-term memory differs in signers and speakers: Implications for models of short-term memory. Cognition, 107, 433–459). We administered a serial recall task with stimuli in Italian Sign Language to 12 deaf people, and we compared their performance with that of twelve age-, gender-, and education-matched hearing participants who performed the task in Italian. The results do not offer evidence for the hypothesis that serial order per se is a detrimental factor for deaf participants. An alternative explanation for the lower sign span based on signs being phonologically heavier than words is considered.
Peer Relationships of Deaf Children With Cochlear Implants: Predictors of Peer Entry and Peer Interaction Success
This study investigated factors that affect the development of positive peer relationships among deaf children with cochlear implants. Ten 5- to 6-year-old deaf children with implants were observed under conditions varying peer context difficulty in a Peer Entry task. Results revealed better outcomes for deaf children interacting in one-on-one situations compared to interactions including two other hearing children and better performance among girls than boys. In addition, longer duration of implant use and higher self-esteem were associated with better performance on the Peer Task, which was in turn related to parental reports of children’s social functioning outside the experimental situation. These findings contribute to the growing literature describing the benefits of cochlear implantation in the areas of communication and socialization, while pointing to interventions that may enhance deaf children’s social competence.
Reading and Spelling Abilities of Deaf Adolescents With Cochlear Implants and Hearing Aids
A total of 86 deaf children aged between 12 and 16 years were recruited from schools for the deaf, specialist units attached to a school, and mainstream schools. Approximately one-third used hearing aids, one-third had received a cochlear implant before 42 months, and one-third had been implanted later. The 3 subgroups were matched for age and nonverbal IQ, and all had an unaided hearing loss of at least 85 dB. Assessments revealed mean reading ages that were several years below chronological age for all 3 groups. However, participants in the hearing aid group performed best. Reading levels were not predicted by age of diagnosis or degree of hearing loss, but there was a relationship between reading level and presence of phonetic errors in spelling. There were also differences in educational setting, with the great majority of children in the hearing aid group in a school for the deaf and relatively more of the children with cochlear implants being educated in a unit or mainstream setting.
The “Wh” Questions of Visual Phonics: What, Who, Where, When, and Why
Visual Phonics is a reading instructional tool that has been implemented in isolated classrooms for over 20 years. In the past 5 years, several experimental studies demonstrated its efficacy with students who are deaf or hard of hearing. Through a national survey with 200 participants, this study specifically addresses who, where, how, and why a sample of teachers use Visual Phonics in their everyday reading instruction. Through checklists of teaching practice, rating scales, and open-ended questions, teachers self-reported their use of Visual Phonics, reflected upon its efficacy, and what they think about using it with students with a diverse set of instructional needs. The majority reported that Visual Phonics was easy to use, engaging to students, and easy to integrate into a structured reading curriculum. The majority of respondents agreed that it helps increase phonemic awareness and decoding skills, build vocabulary, as well as increase reading comprehension. The implications of these findings in bridging the research-to-practice gap are discussed.
Using Miscue Analysis to Assess Comprehension in Deaf College Readers
For over 30 years, teachers have used miscue analysis as a tool to assess and evaluate the reading abilities of hearing students in elementary and middle schools and to design effective literacy programs. More recently, teachers of deaf and hard-of-hearing students have also reported its usefulness for diagnosing word- and phrase-level reading difficulties and for planning instruction. To our knowledge, miscue analysis has not been used with older, college-age deaf students who might also be having difficulty decoding and understanding text at the word level. The goal of this study was to determine whether such an analysis would be helpful in identifying the source of college students’ reading comprehension difficulties. After analyzing the miscues of 10 college-age readers and the results of other comprehension-related tasks, we concluded that comprehension of basic grade school-level passages depended on the ability to recognize and comprehend key words and phrases in these texts. We also concluded that these diagnostic procedures provided useful information about the reading abilities and strategies of each reader that had implications for designing more effective interventions.
Music therapy protocol development to enhance swallowing training for stroke patients with dysphagia.
Considering the devastating condition of dysphagia, it is necessary to provide intensive therapeutic regimen based on interdisciplinary approach. In this aspect, music-enhanced swallowing protocol was developed through a pilot study. Then, the modified protocol from a pilot study was examined with 8 stroke patients in a local hospital. The protocol was designed to improve oral motor control, laryngeal elevation, breathing, and swallowing functions. The dependent variables measured included reflex, respiration, and laryngeal functions using the Frenchay Dysarthria assessment. Results from the initial to the midevaluation showed that pitch in the laryngeal category were statistically significant after 6th sessions. After the 12th session, when the final evaluation was compared with the initial assessment, additional categories revealed statistically significant changes. It is recommended that this study should be replicated with a control group and a larger sample using either FEES or video fluoroscopy for scientific data to further substantiate music therapy outcomes in stroke rehabilitation.
