News and Events

June, 2014 - Dr. John Whyte, director of the Moss Rehabilitation Institute is a primary author on a research paper that has been awarded the Mitchell Rosenthal Award for the best scientific publication using the NIDRR-funded Traumatic Brain Injury Model Systems National Database. The title of the paper is " Functional Outcomes in Traumatic Disorders of Consciousness: 5-Year Outcomes From the National Institute on Disability and Rehabilitation Research Traumatic Brain Injury Model Systems."  PMID 23732164 
May, 2014 - Dr. Tessa Hart presented the keynote address at the New Jersey Brain Injury Alliance annual conference on May 16, 2014. Dr. Hart told the audience of several hundred brain injury professionals and consumers about treatment models based on self-regulation models, including several that are being tested in her lab at MRRI.
May, 2014 - the Cognition and Action Lab directed by Dr. Laurel Buxbaum presented two posters at the Concepts, Actions, and Objects Meeting in Rovereto, Italy
April, 2014 - Dr. Laurel Buxbaum, and other colleagues, published an article in Brain titled, Critical brain regions for tool-related and imitative actions: a componential analysis.
April, 2014 - Dr. Laurel Buxbaum, and other colleagues, published an article in Neuropsychologia titled, Abnormal dynamics of activation of object use information in apraxia: Evidence from eyetracking.
April, 2014 - Dr. Tessa Hart is the lead author on a publication appearing in the April 1, 2014 issue of Journal of Neurotrauma. In a large sample of people with traumatic brain injury (TBI), Hart and her colleagues examined the factors that predicted various patterns of recovery of psychiatric symptoms during the first 6 months after injury.
Early Trajectory of Psychiatric Symptoms after Traumatic Brain Injury: Relationship to Patient and Injury Characteristics. Tessa Hart, Emma K.T. Benn, Emilia Bagiella, Patricia Arenth, Sureyya Dikmen, Dale C. Hesdorffer, Thomas A. Novack, Joseph H. Ricker, Ross Zafonte
Journal of Neurotrauma. April 1, 2014, 31(7): 610-617.
March, 2014 - Dr. John Whyte, director of MRRI gave the keynote address at the 10th International Brain Injury Association meeting in San Francisco. The talk, to about 1200 people, was entitled: A Phased Developmental Approach to Neurorehabilitation Research: The Science of Knowledge Building
March, 2014 - Postdoctoral Fellows Konstantinos Tsagkaridis and Christine Watson, along with Institute Scientists Laurel Buxbaum and Steve Jax, have a new paper in "Frontiers in Human Neuroscience" on the role that action knowledge plays in understanding the relationships between everyday objects.
January, 2014 - Dr. Laurel Buxbaum published an article in Cortex titled, Moving the gesture engram into the 21st Century.
January, 2014 - A special supplement to the Archives of Physical Medicine and Rehabilitation was published entitled "Toward a Taxonomy of Rehabilitation Treamtents." The supplement contains a collection of articles that are the product of a 5-year NIDRR-funded project to address the lack of any formal system for defining and organizing the many non-drug treatments that occur in rehabilitation. The project was led by Marcel Dijkers at the Icahn School of Medicine at Mt. Sinai, but MRRI staff Tessa Hart, John Whyte, Andy Packel, and Mary Ferraro were key authors on many of the articles.
November, 2013 - Dr. Laurel Buxbaum, along with former postdoctoral fellow Dr. Solene Kalenine and other colleagues, published an article in the Psychonomic Bulletin and Review focusing on the influence of visual context on activation of object-related action information.
October 7 & 8, 2013 -Four external consultants who are known experts in different areas of rehabilitation research came to the Moss Rehabilitation Research Institute for a strategic planning meeting.
October, 2013 - John Whyte was co-Editor, with Risa Nakase-Richardson, of the most recent issue of Archives on Physical Medicine and Rehabilitation that has a topical focus on Disorders Of Consciousness. Dr. Whyte co-authored the introductory piece, and was also first author on 2 of the research publications within the same issue.
October, 2013 - NARRTC selects paper published by John Whyte and colleagues "The Best Research Paper for 2013"
June, 2013 - Tessa Hart, PhD received the Mitchell Rosenthal Award in June, 2013 for the best manuscript published on the Traumatic Brain Injury Model System National Database. The paper, entitled "Participant-proxy agreement on objective and subjective aspects of societal participation following traumatic brain injury," was published in the Journal of Head Trauma Rehabilitation in 2010. Dr. Hart's co-authors on this paper included MRRI's Director, John Whyte, MD, PhD as well as collaborators at TIRR/ Memorial Hermann in Houston, the University of Washington in Seattle, and the Rehabilitation Institute of Chicago.
June, 2013 - John Whyte, MD, PhD and Tessa Hart, PhD co-led an intensive 3-day Rehabilitation Treatment Taxonomy Workshop in June, 2013 in Rockville, MD, which included about 40 invited participants from the US, UK and Europe representing all major disciplines and many organizations involved in medical rehabilitation. Drs. Hart and Whyte, along with other colleagues from Moss and Mt. Sinai School of Medicine in New York, presented a framework for defining and classifying treatments in rehabilitation according to their active ingredients and mechanisms of action. This work has been funded since 2008 by a cooperative agreement by the National Institute on Disability and Rehabilitation Research, with Marcel Dijkers, PhD of Mt. Sinai as Principal Investigator.
September, 2013 - New article by Dr. Gary Dell, Dr. Myrna Schwartz and colleagues on voxel-based lesion mapping of parameters of a computational model of language production published in the journal Cognition.
June 10, 2013 - Dr. Dan Mirman presented an invited talk entitled "What we talk about when we talk about access deficits" at a scientific discussion meeting on language in developmental and acquired disorders hosted by The Royal Society in London, UK.
June 10, 2013 - Dr. Myrna Schwartz presented an invited talk entitled "Word production deficits in adult aphasia" at a scientific discussion meeting on language in developmental and acquired disorders hosted by The Royal Society in London, UK.
June, 2013 - New article by Dr. Solene Kalenine, Allison Shapiro, and Dr. Laurel Buxbaum on means and outcomes processing of action published in the journal Neuropsychologia.
June, 2013 - New article by Dr. Dan Mirman, Allison Britt, and Dr. Qi Chen on facilitative and inhibitory effects of item repetition published in the journal Neuropsychologia.
June, 2013 - Dr. Myrna Schwartz's development of a short-form Philadelphia Naming Test highlighted by Psychology Progress
May, 2013 - Dr. Laurel Buxbaum gave an invited talk at the Concepts, Actions, and Objects (CAOS) annual workshop in Rovereto, Italy, entitled “Actions and Objects: Competition, Facilitation, and Conceptual Organization”.
May 6, 2013 - New article by Dr. Daniel Mirman and Kristen Graziano on the neural basis of lexical neighborhood effects published in the Journal of Cognitive Neuroscience
April, 2013 - Dr. Erin Vasudevan was an invited presenter & panelist at Neuroedge 2013: An International Neurology Update in Mumbai, India. She spoke on gait and posture disorders.
April, 2013 - The Cognition and Action Lab presented 4 posters at the Cognitive Neuroscience Society Meeting in San Francisco.
March, 22, 2013 - Dr. Laurel Buxbaum gave an invited talk at the Symposium on Behavioral Neurology in Lucerne, Switzerland, entitled “Competitive interactions between action representations in apraxia”.
February 26, 2013 - New article by Dr. Junghoon Kim and colleagures titled, “Methodological considerations in longitudinal structural morphometry of traumatic brain injury,” published in Frontiers in Human Neuroscience. PMCID 3581852
November 20, 2012 - New article about the neural basis of phonological retreival in object naming by Dr. Myrna Schwartz and colleagues published in Brain.
October, 2012 - Dr. Laurel Buxbaum gave a presentation at the Hospital of the University of Pennsylvania Neurology Grand Rounds titled "Limb apraxia in left hemisphere stroke:  Recent developments".
August 10, 2012 - New article by Ferdinand Binkofski and Dr. Laurel Buxbaum about the two action systems in the human brain published in Brain and Language
October 2, 2012 - Dr. John Whyte selected for the 2012 Council on Brain Injury Award.
September 26, 2012 - New article on sub-specialization in frontal cortex for different linguistic and executive functions by Dr. Malathi Thothathiri, Maureen Gagliardi, and Dr. Myrna Schwartz published in Neuropsychologia.
September, 2012 - Dr. Tessa Hart's Traumatic Brain Injury Model System grant was renewed by NIDRR for another 5 years.
September, 2012 - Dr. Erica Middleton was awarded a grant from NIDCD to apply principles of learning and memory to improving treatments for aphasia.
April, 2012 - John Whyte presented a webinar for the Brain Trauma Foundation on "Assessment and Prognosis in Severe TBI", which is now freely available at
August 1, 2012 - New article on the role of competition between appropriate and inappropriate actions in ideomotor apraxia by Dr. Steven Jax and Dr. Laurel Buxbaum.
July 20, 2012 - Dr. Laurel Buxbaum had been promoted to Professor in the Department of Rehabilitation Medicine at Thomas Jefferson University.
July 17, 2012 - MossRehab named one of the top 10 rehabilitation hospitals in the country and #1 in Pennsylvania by US News and World Report. This is the 19th year that MossRehab has appeared in U.S.News & World’s Report’s rankings.
July 1, 2012 -Dr. Erin Vasudevan was awarded a National Scientist Development Grant from the American Heart Association for a project titled "Optimizing Locomotor Adaptation for Rehabilitation Post-Stroke".
May 28, 2012 - New article about using Virtual Reality to assess hemispatial neglect by Dr. Laurel Buxbaum, Dr. Amanda Dawson, and Drew Linsley published in Neuropsychology.
May 28, 2012 - New article by Dr. Gary Lupyan and Dr. Dan Mirman about the relationship between language and categorization in aphasia published in Cortex.
May 18, 2012 - Dr. Tessa Hart presented a keynote lecture and received the Norington Medal at the Congress of the World Federation of NeuroRehabilitation in Melbourne, Australia. Dr. Hart's talk was entitled "Self-Regulation Concepts in Brain Injury Rehabilitation." At the same meeting she also conducted a half-day workshop on remediation of executive dysfunction in brain injury.
May 6, 2012 - New article by Dr. Dan Mirman and Kristen Graziano about the neural basis of thematic semantic impairments published in Neuropsychologia.
May 4, 2012 - New article about functional and thematic semantic deficits following left hemisphere stroke by Solene Kalenine, Dan Mirman, and Laurel Buxbaum published in Frontiers in Human Neuroscience.
April 25, 2012 - Aphasia Center wins Inglis Foundation Award for Continuing Excellence.
Press Release:
April 20, 2012 - New article about interference between functional and structural object-related actions in patients with ideomotor apraxia by Steve Jax and Laurel Buxbaum published in Journal of Neuropsychology.
April 20, 2012 - Dr. Tessa Hart, Institute Scientist and Director of the Traumatic Brain Injury (TBI) Clinical Research Laboratory, was invited to join a national work group of TBI experts to prepare a report to the Congress of the United States on the scientific evidence bearing on the efficacy and effectiveness of TBI rehabilitation. Commissioned by the Centers for Disease Control and Prevention (CDC), this report will also provide recommendations to Congress for how to fill the gaps in the current state of the science on TBI rehabilitation research.
April 4, 2012 - Erin Vasudevan presented a talk titled "Learning about motor learning: Neurophysiologic and rehabilitation insights from split-belt adaptation" to the Drexel University Department of Neurobiology & Anatomy.
April 3, 2012 -Laurel Buxbaum presented a talk titled "Cognitive and neuroanatomical substrates of action events" as part of a cross-disciplinary symposium about understanding events at the 19th Annual Cognitive Neuroscience Society Meeting.
April 3, 2012 - Post-docs Solene Kalenine, Qi Chen, Erica Middleton, and Chia-lin (Charlene) Lee each presented posters at the 19th Annual Cognitive Neuroscience Society Meeting.
April 3, 2012 - John Whyte awarded the Kessler Foundation’s Joel A. DeLisa, MD Award for Excellence in Research and Education in the Field of Physical Medicine and Rehabilitation.
March 26, 2012 - New article about the time course of activation of thematic and functional knowledge by Solene Kalenine, Daniel Mirman, Erica Middleton, and Laurel Buxbaum published in Journal of Experimental Psychology: Learning, Memory, and Cognition.
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March 5, 2012 - New article about the activation of different types of action information during object identification by Charlene Lee, Erica Middleton, Dan Mirman, Solene Kalenine, and Laurel Buxbaum published in Journal of Experimental Psychology:  Human Perception and Performance.
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March 1, 2012 - New article by John Whyte and colleagues on a placebo-controlled trial of amantadine for severe traumatic brain injury published in the New England Journal of Medicine.
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Coverage in the New York Times: 
February 14, 2012 - Steven Jax awarded NIH R01 grant titled "Home-based mirror therapy for treating hemiparesis in stroke patients"

Summary: Each year in the United States 550,000 people develop upper-extremity movement deficits after stroke (hemiparesis). The recent success of mirror therapy (MT) is notable because it is a simple treatment for hemiparesis, and may be feasible for home use. MT uses a standard mirror to create a compelling illusion in which movements of the unimpaired limb appear as if they are being made by the impaired limb. We propose to complete a randomized placebo-controlled clinical trial of MT with a target enrollment of 100 chronic stroke patients. The therapy will consist of a standardized set of hand, wrist, and elbow movements completed in two daily 30-minute sessions, 5 times per week for 4 weeks. Patients assigned to the placebo treatment (identical therapy with an opaque divider rather than a mirror) will be crossed over to receive MT after a three month follow-up. The first goal of the study will be to determine whether a home-based form of MT is an effective treatment of hemiparesis. Providing evidence that mirror therapy could be administered at home would have enormous implications for the cost of treating hemiparesis, especially relative to alternative treatments that require a significant amount of therapist time (constraint-induced movement therapy) or expensive equipment (robotic training). Pilot data suggest that home-based mirror therapy could lead to clinically significant improvements in functioning. The second goal will be to determine the optimal dosing of MT by including weekly measures of improvement. The third goal will be to understand individual differences in the efficacy of mirror therapy. Previous MT studies have not reported, or lacked the power to test, why some patients benefit from MT and others do not, even though significant individual differences have been reported. Our use of a large sample of patients will allow us to assess predictors of therapeutic benefit. Being able to predict beneficial clinical outcomes would be quite innovative because this issue is rarely addressed in rehabilitation research more generally and is crucial to the real world task of treatment selection for individual patients.

Febrary 22, 2012 - New article about the neural correlates of sustained attention and working memory deficits in traumatic brain injury by Junghoon Kim, John Whyte, and colleagues published in Neurorehabilitation and Neural Repair.
December 28, 2011 - New article about the neural basis of methylphenidate (MPH) modulation of sustained attention in traumatic brain injury by Junghoon Kim, John Whyte, and colleagues published in Psychopharmacology.
Febrary 22, 2012 - John Whyte's research on effects of Ambien (zolpitem) in minimally conscious patients featured in Philadelphia Inquirer:
Febrary 20, 2012 - New article about competition and cooperation among lexical neighbors by Qi Chen and Dan Mirman published in Psychological Review:
January 27, 2012 - Buxbaum et al. article “Left inferior parietal representations for skilled hand-object interactions: Evidence from stroke and corticobasal degeneration” (Vol. 43, #3, 2007, pp. 411-423) one of the top 10 most cited articles in Cortex:
January 23, 2012 - New article describing short forms of the Philadelphia Naming Test by Grant Walker and Myrna Schwartz in American Journal of Speech-Language Pathology

Abstract: Purpose: To create two matched short forms of the Philadelphia Naming Test (PNT) that yield similar results to the PNT for measuring anomia. Methods: Study 1: We first used archived naming data from 94 aphasic individuals to identify which PNT items should be included in the short forms, and the two constructed sets of 30 items, PNT30-A and PNT30-B, were validated using archived data from a separate group of 56 aphasic individuals. Study 2: We then evaluated the reliability of the PNT, PNT30-A, and PNT30-B across independent test administrations with a new group of 25 aphasic individuals selected to represent the full range of naming impairment. Results: Study 1: PNT30-A and PNT30-B were found to be internally consistent; and accuracy scores on these subsets of items were highly correlated with the full PNT. Study 2: PNT accuracy was extremely reliable over the span of one week; and independent administrations of PNT30-A and PNT30-B produced similar results to the PNT and to each other. Conclusions: The short forms can be used to reliably estimate PNT performance, and the results can be compared to the provided norms. The two matched tests allow for measurement of change in naming ability.

January 16, 2012 - New review article about errorless learning in cognitive rehabilitation by Erica Middleton and Myrna Schwartz in Neuorpsychological Rehabilitation (DOI:10.1080/09602011.2011.639619)

Abstract: Cognitive rehabilitation research is increasingly exploring errorless learning interventions, which prioritise the avoidance of errors during treatment. The errorless learning approach was originally developed for patients with severe anterograde amnesia, who were deemed to be at particular risk for error learning. Errorless learning has since been investigated in other memory-impaired populations (e.g., Alzheimer's disease) and acquired aphasia. In typical errorless training, target information is presented to the participant for study or immediate reproduction, a method that prevents participants from attempting to retrieve target information from long-term memory (i.e., retrieval practice). However, assuring error elimination by preventing difficult (and error-permitting) retrieval practice is a potential major drawback of the errorless approach. This review begins with discussion of research in the psychology of learning and memory that demonstrates the importance of difficult (and potentially errorful) retrieval practice for robust learning and prolonged performance gains. We then review treatment research comparing errorless and errorful methods in amnesia and aphasia, where only the latter provides (difficult) retrieval practice opportunities. In each clinical domain we find the advantage of the errorless approach is limited and may be offset by the therapeutic potential of retrieval practice. Gaps in current knowledge are identified that preclude strong conclusions regarding a preference for errorless treatments over methods that prioritise difficult retrieval practice. We offer recommendations for future research aimed at a strong test of errorless learning treatments, which involves direct comparison with methods where retrieval practice effects are maximised for long-term gains.

January 1, 2012 - Dan Mirman, Institute Scientist, appointed to editorial board of Journal of Memory and Language
December 26, 2011 - John Whyte, MRRI Director and Institute Scientist, featured on NBC Rock Center segment about Zolpidem (Ambien) treatment for minimally conscious patients
December 22, 2011 - Hart et al. article “Major and Minor Depression After Traumatic Brain Injury” (Vol. 92, #8, 2011, pp. 1211-1219) is in the Top 25 Hottest Articles (July-September 2011) in Archives of Physical Medicine and Rehabilitation:
December 4, 2011 - MRRI Director and Institute Scientist John Whyte's research on minimally conscious states featured in a New York Times Magazine article:
Oct. 2011 - Tessa Hart, Institute Scientist, has been appointed to the expanded effort to develop Common Data Elements (CDE) for research on traumatic brain injury (TBI) and other populations important to develop new knowledge in neuroscience. Sponsored by the National Institutes of Health, the National Institute on Disability and Rehabilitation Research, the Department of Veterans Affairs, and other national and international stakeholders, the CDE project seeks to standardize the collection of investigational data in order to facilitate comparison of results across studies and more effectively aggregate information into significant metadata results. Dr. Hart has joined a team of investigators and federal sponsor representatives to develop core indices of patient characteristics, treatment variables, and outcomes that will foster project objectives by harmonizing research findings across nations, laboratories, and clinical settings.
October 11, 2011 - New IOM report on Cognitive Rehabilitation Therapy for TBI is published. It was co-authored by John Whyte, Institute Scientist, and includes expert input from Institute Scientists John Whyte and Tessa Hart
Oct. 2011 - Laurel Buxbaum, Institute Scientist, appointed to the Editorial Board of the journal Cortex
8/23/11 - New article by Malathi Thothathiri (former post-doc), Dan Kimberg, and Myrna Schwartz (Institute Scientist) on the neural basis of sentence comprehension in the Journal of Cognitive Neuroscience (doi:10.1162/jocn_a_00118)

Abstract: We explored the neural basis of reversible sentence comprehension in a large group of aphasic patients (N = 79).
Voxel-based lesion symptom mapping revealed a significant association between damage in temporo-parietal cortex and impaired sentence comprehension. This association remained after we controlled for phonological working memory. We hypothesize that this region plays an important role in the thematic or what-where processing of sentences.
In contrast, we detected weak or no association between reversible sentence comprehension and the ventrolateral pFC, which includes Broca's area, even for syntactically complex sentences. This casts doubt on theories that presuppose a critical role for this region in syntactic computations.

Video Presentation (Using tDCS to Improve Aphasia Treatment Outcome) by visiting scholar Julius Fridriksson, PhD has been posted to YouTube.
Laurel Buxbaum, Institute Scientist, will become Associate Editor of the journal Cognition in October
Tessa Hart, Institute Scientist, is now President-elect of Division 22 (Rehabilitation Psychology) of the American Psychological Association
8/3/11 - New article by Laurel Buxbaum and colleagues Krish Sathian, Leo Cohen, John Krakauer, Catherine Lang, Maurizio Corbetta, and Susan Fitzpatrick on rehabilitation of action disorders in the journal Neurorehabilitation and Neural Repair.
PMID: 21613535

Abstract: In this chapter, the authors use the computation, anatomy, and physiology (CAP) principles to consider the impact of common clinical problems on action. They focus on 3 major syndromes: paresis, apraxia, and ataxia. They also review mechanisms that could account for spontaneous recovery, using what is known about the best-studied clinical dysfunction--paresis--and also ataxia. Together, this and the previous chapter lay the groundwork for the third chapter in this series, which reviews the relevant rehabilitative interventions.

4/26/11 - Walker, GM, Jacobson, R., and Schwartz, MF (June, 2011). Short-form Philadelphia Naming Test: Rationale and Empirical Evaluation. Presented at the 2011 Clinical Aphasiology Conference, Ft. Lauderdale, FL, USA.
5/13/2011 - Palluel-Germain, R., Jax, S.A., & Buxbaum, L.J. (in press). Visuo-motor gain adaptation and generalization following left hemisphere stroke. Neuroscience Letters. doi:10.1016/j.neulet.2011.05.015

Abstract: During gain adaptation, participants must learn to adapt to novel visuo-motor mappings in which the movement amplitudes they produce do not match the visual feedback they receive. The aim of the present study was to investigate the neural substrates of gain adaptation by examining its possible disruption following left hemisphere stroke. Thirteen chronic left hemisphere stroke patients and five healthy right-handed control subjects completed three experimental phases involving reaching with the left hand, which was the less-affected hand in patients. First, participants reached without visual feedback to six different target locations (baseline phase). Next, in the adaptation phase, participants executed movements to one target under conditions in which the perceived movement distance was 70% of the produced movement distance. Last, in order to test the generalization of this new visuomotor mapping, participants made movements without visual feedback to untrained target locations (generalization phase). Significant between-patient differences were observed during adaptation. Lesion analyses indicated that these between-patient differences were predicted by the amount of damage to the supramarginal gyrus (Brodmann area 40). In addition, patients performed more poorly than controls in the generalization phase, suggesting that different processes are involved in adaptation and generalization periods.

4/26/11 - Dr. Laurel Buxbaum gave an invited talk entitled "Two action systems in the human brain:  functional neuroanatomy and relationship to apraxia" at Neurorehabilitation Grand Rounds at Washington University in St. Louis.
5/17/2011- Schwartz MF, Kimberg DY, Walker GM, Brecher A, Faseyitan OK, Dell GS, Mirman D, & Coslett HB (2011). Neuroanatomical dissociation for taxonomic and thematic knowledge in the human brain. Proceedings of the National Academy of Sciences, 108(20):8520-8524. Featured on the cover!

Abstract: It is thought that semantic memory represents taxonomic information differently from thematic information. This study investigated the neural basis for the taxonomic-thematic distinction in a unique way. We gathered picture-naming errors from 86 individuals with poststroke language impairment (aphasia). Error rates were determined separately for taxonomic errors ("pear" in response to apple) and thematic errors ("worm" in response to apple), and their shared variance was regressed out of each measure. With the segmented lesions normalized to a common template, we carried out voxel-based lesion-symptom mapping on each error type separately. We found that taxonomic errors localized to the left anterior temporal lobe and thematic errors localized to the left temporoparietal junction. This is an indication that the contribution of these regions to semantic memory cleaves along taxonomic-thematic lines. Our findings show that a distinction long recognized in the psychological sciences is grounded in the structure and function of the human brain.

May 2011 - Tessa Hart, PhD and John Whyte, MD, PhD were both invited to participate on the Technical Expert Panel for a new, comprehensive systematic review titled "Comparative Effectiveness of Postacute Rehabilitation for Moderate to Severe Traumatic Brain Injury in Adults". This national project, which is being conducted as part of the Agency for Healthcare Research and Quality's (AHRQ) Effective Health Care Program, seeks to establish treatment guidelines and practice standards for post-acute TBI rehabilitation to be used by clinicians, patients, and policymakers making healthcare decisions.
4/23/2011 - Vasudevan EV & Zehr EP (2011). Multi-frequency arm cycling reveals bilateral locomotor coupling to increase movement symmetry. Experimental Brain Research, 211(2):299-312. PMID: 21516330.

Abstract: Upright stance has allowed for substantial flexibility in how the upper limbs interact with each other: the arms can be coordinated in alternating, synchronous, or asymmetric patterns. While synchronization is thought to be the default mode of coordination during bimanual movement, there is little evidence for any bilateral coupling during locomotor-like arm cycling movements. Multi-frequency tasks have been used to reveal bilateral coupling during bimanual movements, thus here we used a multi-frequency task to determine whether the arms are coupled during arm cycling. It was hypothesized that bilateral coupling would be revealed as changes in background EMG and cutaneous reflexes when temporal coordination was altered. Twelve subjects performed arm cycling at 1 and 2 Hz with one arm while the contralateral arm was either at rest, cycling at the same frequency, or cycling at a different frequency (i.e., multi-frequency cycling with one arm at 1 Hz and the other at 2 Hz). To evoke reflexes, the superficial radial nerve was stimulated at the wrist. EMG was collected continuously from muscles of both arms. Results showed that background EMG in the lower frequency arm was amplified while reflex amplitudes were unaltered during multi-frequency cycling. We propose that neural coupling between the arms aids in equalizing muscle activity during asymmetric tasks to permit stable movement. Conversely, such interactions between the arms would likely be unnecessary in determining a reflexive response to a perturbation of one arm. Therefore, bilateral coupling was expressed when it was relevant to symmetry.

7/1/2011- Dr. Erin Vasudevan will present at the "Physiological Principles of Locomotion Required for Robot Design" workshop during the International Conference on Rehabilitation Robotics in Zurich, Switzerland.
4/2011 - Dr. Tessa Hart was involved in the development of a new measure of societal participation which is featured in a special section of the April, 2011 issue of Archives of Physical Medicine and Rehabilitation. The "Participation Assessment with Recombined Tools- Objective" (PART-O) is the product of years of multi-center research in which existing measures of participation were combined and streamlined into a new measure that captures the best features of each. Dr. Hart co-authored the article introducing the PART-O (Whiteneck GG, Dijkers MP, Heinemann AW, Bogner JA, Bushnik T, Cicerone KD, Corrigan JD, Hart T, Malec JF, Millis SR. Development of the Participation Assessment with Recombined Tools-Objective for use after traumatic brain injury. Archives of Physical Medicine and Rehabilitation, 92:542-551, 2011.) PMID: 21367393 Other articles in the same issue present scoring algorithms and conceptual issues involved in the measurement of participation.
4/2011 Dr. Charlene Lee and Dr. Laurel Buxbaum received a $35,000 grant from the Albert Einstein Society for a project entitled "Priming of Functional and Structural Action Information".  The project is focused on improving our understanding of the cognitive mechanisms underlying object-related actions.
3/31/2011 Dr. Laurel Buxbaum gave an invited talk entitled "Therapeutic Options for Person with Right Hemisphere Stroke" at the Research Institute of Chicago's Annual Interdisciplinary Stroke Course.
3/3/2011 Myrna Schwartz presented the Siegel-Wallston Invited Address at the 57th Annual Meeting of the Southeastern Psychological Association: "How the Mind and Brain Access the Names for Things: Evidence from Access Failures in Aphasia"
3/2/2011 - Mirman, D., Yee, E., Blumstein, S.E., & Magnuson, J.S. (in press). Theories of spoken word recognition deficits in Aphasia: Evidence from eye-tracking and computational modeling. Brain & Language. doi:10.1016/j.bandl.2011.01.004

Abstract: We used eye-tracking to investigate lexical processing in aphasic participants by examining the fixation time course for rhyme (e.g., carrot–parrot) and cohort (e.g., beaker–beetle) competitors. Broca’s aphasic participants exhibited larger rhyme competition effects than age-matched controls. A re-analysis of previously reported data (Yee, Blumstein, & Sedivy, 2008) confirmed that Wernicke’s aphasic participants exhibited larger cohort competition effects. Individual-level analyses revealed a negative correlation between rhyme and cohort competition effect size across both groups of aphasic participants. Computational model simulations were performed to examine which of several accounts of lexical processing deficits in aphasia might account for the observed effects. Simulation results revealed that slower deactivation of lexical competitors could account for increased cohort competition in Wernicke’s aphasic participants; auditory perceptual impairment could account for increased rhyme competition in Broca’s aphasic participants; and a perturbation of a parameter controlling selection among competing alternatives could account for both patterns, as well as the correlation between the effects. In light of these simulation results, we discuss theoretical accounts that have the potential to explain the dynamics of spoken word recognition in aphasia and the possible roles of anterior and posterior brain regions in lexical processing and cognitive control.

2/25/2011 Tessa Hart was presented with the 2011 Leonard Diller award from Division 22 (Rehabilitation Psychology) of the American Psychological Association. This award honors clinical scientists who have made significant scholarly contributions to the field of neurorehabilitation. After receiving the award at the 13th Annual Conference on Rehabilitation Psychology in Jacksonville, FL, Dr. Hart presented the keynote Leonard Diller Lecture: "Theories for Rehabilitation: What and Why?"
2/7/2011 - John Whyte, MD, PhD, Director, and Tessa Hart, PhD, Institute Scientist participate in newly commissioned Institute of Medicine Committee on Cognitive Rehabilitation Therapy for Traumatic Brain Injury.

John Whyte, MD, PhD, Director, and Tessa Hart, PhD, Institute Scientist, were both invited to participate in a newly commissioned Institute of Medicine panel in Washington, DC. Dr. Whyte was invited to be a member of the Committee on Cognitive Rehabilitation Therapy for Traumatic Brain Injury, and Dr. Hart was invited to address the Committee to discuss the cognitive consequences of TBI. Over the next few months, Dr. Whyte and other Committee members will examine the evidence on cognitive rehabilitation to formulate recommendations for treatment of service members with TBI for the US Department of Defense.

2/7/2011 - Junghoon Kim, PhD, Institute Scientist, awarded NINDS R01 grant “A Longitudinal Multi-modal Neuroimaging Investigation of Functional Recovery after Diffuse Traumatic Brain Injury."

Abstract: While it is well established that behavioral outcome measures show significant improvements over months and even years after the injury, the underlying neural mechanisms of such recovery are not well understood. Based on our preliminary work, the current project aims 1) to determine the pattern of longitudinal changes in structural and functional neuroimaging indices associated with moderate to severe diffuse axonal injury and their relationship with behavioral improvements, 2) to develop a neuropathologically based injury severity measure using longitudinal changes in the early post-acute phase, and 3) to develop a “structure-function discrepancy” index, based on the difference between the integrity of structural and functional imaging measures obtained at different points of post-injury, and collect preliminary data on its relationship with behavioral recovery. We propose to evaluate 60 individuals with moderate to severe diffuse TBI in the post-acute phase with structural and functional neuroimaging measures at multiple time points. Thirty six demographically matched healthy control subjects will be evaluated for comparison purposes. To measure longitudinal improvements in behavior, a global behavioral outcome measure and a neuropsychological test battery consisting of five executive function tests will be administered at each time point.

Laurel Buxbaum, Institute Scientist, joins editorial board of Cognitive Neuroscience
New article about development of locomotor adaptation: Vasudevan EV, Torres-Oviedo G, Morton SM, Yang JF, and Bastian AJ (in press). Younger is not always better: development of locomotor adaptation from childhood to adulthood. Journal of Neuroscience.
New Research Assistant joins Clinical Neuroimaging Laboratory: Dan Sasse
New review article on treatments of action disorders: Sathian, K., Buxbaum, L., Cohen, L., Krakauer, J.W., Lang, C., Corbetta, M., and Fitzpatrick, S. M. (in press) Neurological Principles and Rehabilitation of Action Disorders: Common Clinical Deficits. Neurorehabilitation and Neural Repair.
Myrna Schwartz, Institute Scientist, presents "How the mind and brain access the names for things: Evidence from aphasia" in Neurology Grand Rounds at Penn (Dec. 10, 2010).
New article on anger self-management training for people with TBI: Hart T, Vaccaro M, Hays C, Maiuro R. (in press). Anger self-management training for people with traumatic brain injury: A preliminary investigation. Journal of Head Trauma Rehabilitation.
New article on picture naming and word repetition in aphasia: Nozari, N., Kittredge, A.K., Dell, G.S., and Schwartz, M.F. (2010) Naming and repetition in aphasia: Steps, routes, and frequency effects. Journal of Memory and Language, 63, 541-559. PMID 21076661, PMCID 2976549 [Available on 2011/11/1]

Abstract: This paper investigates the cognitive processes underlying picture naming and auditory word repetition. In the two-step model of lexical access, both the semantic and phonological steps are involved in naming, but the former has no role in repetition. Assuming recognition of the to-be-repeated word, repetition could consist of retrieving the word’s output phonemes from the lexicon (the lexical-route model), retrieving the output phonology directly from input phonology (the nonlexical-route model) or employing both routes together (the summation dual-route model). We tested these accounts by comparing the size of the word frequency effect (an index of lexical retrieval) in naming and repetition data from 59 aphasic patients with simulations of naming and repetition models. The magnitude of the frequency effect (and the influence of other lexical variables) was found to be comparable in naming and repetition, and equally large for both the lexical and summation dual-route models. However, only the dual-route model was fully consistent with data from patients, suggesting that nonlexical input is added on top of a fully-utilized lexical route.

Mirman, D. (in press). Effects of near and distant semantic neighbors on word production. Cognitive, Affective, and Behavioral Neuroscience.

Abstract: One way to examine the dynamics of word processing is to investigate how processing is affected by the co-activation of similar words (“neighbors”). A unique prediction of attractor dynamical models is that near neighbors should exert inhibitory effects and distant neighbors should exert facilitative effects. In study 1, data from 62 unselected chronic aphasia patients revealed a higher rate of semantic errors for words with many near semantic neighbors and fewer semantic errors for words with many distant semantic neighbors. In study 2, this basic result was replicated in controls using a speeded picture naming paradigm. Together, these two studies provide strong new evidence consistent with the attractor dynamics view of neighborhood effects. In addition, analyses of correlations between effect sizes and lesion locations, and comparisons with the existing literature on semantic deficits in aphasia and the speeded picture-naming paradigm, all provide converging evidence that the semantic error patterns found in the present studies were due to disruptions of cognitive control mechanisms.

Walker, G. M., Schwartz, M. F., Kimberg, D. Y., Faseyitan, O., Brecher, A., Dell, G. S., & Coslett, H.B. (in press). Support for anterior temporal involvement in semantic error production in aphasia: New evidence from VLSM. Brain & Language. PMID 20961612

Abstract: Semantic errors in aphasia (e.g., naming a horse as “dog”) frequently arise from faulty mapping of concepts onto lexical items. A recent study by our group used voxel-based lesion-symptom mapping (VLSM) methods with 64 patients with chronic aphasia to identify voxels that carry an association with semantic errors. The strongest associations were found in the left anterior temporal lobe (L-ATL), in the mid- to anterior MTG region. The absence of findings in Wernicke’s area was surprising, as were indications that ATL voxels made an essential contribution to the post-semantic stage of lexical access. In this follow-up study we sought to validate these results by re-defining semantic errors in a manner that was less theory dependent and more consistent with prior lesion studies. As this change also increased the robustness of the dependent variable, it made it possible to perform additional statistical analyses that further refined the interpretation. The results strengthen the evidence for a causal relationship between ATL damage and lexically-based semantic errors in naming and lend confidence to the conclusion that chronic lesions in Wernicke’s area are not causally implicated in semantic error production.

Visiting Scholar at MRRI: Lawrence Barsalou (Oct. 1, 2010)
Laurel Buxbaum, Institute Scientist, wins the Widener University Alumni Award for Excellence in Professional Psychology (Sept., 2010)
New Institute Scientist joins MRRI: Erin Vasudevan (Sept., 2010)
Buxbaum, L.J., Kalénine, S. (2010). Action knowledge, visuomotor activation, and embodiment in the two action systems. Annals of the New York Academy of Sciences, 1191, 201-218. PMID 20392282

Abstract: Scientific interest in the relationship between cognition and action has increased markedly in the past several years, fueled by the discovery of mirror neurons in monkey prefrontal and parietal cortex and by the emergence of a movement in cognitive psychology, termed the embodied cognition framework, which emphasizes the role of simulation in cognitive representations. Guided by a functional neuroanatomic model called the Two Action Systems account, which posits numerous points of differentiation between structure- and function-based actions, we focus on two of the major issues under recent scrutiny: the relationship between representations for action production and recognition, and the role of action in object representations. We suggest that mirror neurons in humans are not critical for full action understanding, and that only function-based (and not structure-based) action is a component of embodied object concepts.

MRRI moves to new building (July, 2010)
Jax, S. A., & Buxbaum, L. J. (2010). Response interference between functional and structural actions linked to the same familiar object. Cognition, 115(2), 350-355. PMID 20156619

Abstract: Viewing objects with the intention to act upon them may activate task-irrelevant motor responses. Many manufactured objects are associated with two action classes: grasping in accordance with object structure and skillful use consistent with object function. We studied the potential for within-object competition during action selection by comparing initiation latencies for “conflict” objects (with competing structure and function responses) to “non-conflict” objects (with a single response). We demonstrated a novel pattern of within-object interference wherein actions involving conflict objects were slowed when participants skillfully used those objects (grasp-on-use interference) as well as a second pattern of interference when conflict objects were grasped after skillfully using the same objects in previous blocks (long-term use-on-grasp interference). These data suggest that actions to common objects are influenced by competition between rapid but briefly maintained grasp responses and slower but longer-lasting use responses, and advance our understanding of the process and neural substrates of selection for action

Kalenine, S., Buxbaum, L.J., & Coslett, H.B. (2010). Critical brain regions for action recognition: lesion-symptom mapping in left hemisphere stroke. Brain, 133(11), 3269-3280. PMID 20805101

Abstract: A number of conflicting claims have been advanced regarding the role of the left inferior frontal gyrus, inferior parietal lobe and posterior middle temporal gyrus in action recognition, driven in part by an ongoing debate about the capacities of putative mirror systems that match observed and planned actions. We report data from 43 left hemisphere stroke patients in two action recognition tasks in which they heard and saw an action word (‘hammering’) and selected from two videoclips the one corresponding to the word. In the spatial recognition task, foils contained errors of body posture or movement amplitude/timing. In the semantic recognition task, foils were semantically related (sawing). Participants also performed a comprehension control task requiring matching of the same verbs to objects (hammer). Using regression analyses controlling for both the comprehension control task and lesion volume, we demonstrated that performance in the semantic gesture recognition task was predicted by per cent damage to the posterior temporal lobe, whereas the spatial gesture recognition task was predicted by per cent damage to the inferior parietal lobule. A whole-brain voxel-based lesion symptom-mapping analysis suggested that the semantic and spatial gesture recognition tasks were associated with lesioned voxels in the posterior middle temporal gyrus and inferior parietal lobule, respectively. The posterior middle temporal gyrus appears to serve as a central node in the association of actions and meanings. The inferior parietal lobule, held to be a homologue of the monkey parietal mirror neuron system, is critical for encoding object-related postures and movements, a relatively circumscribed aspect of gesture recognition. The inferior frontal gyrus, on the other hand, was not predictive of performance in any task, suggesting that previous claims regarding its role in action recognition may require refinement.