Errol Baker

Semantic field, naming, and auditory comprehension in aphasia.

Abstract The status of semantic fields for 16 target nouns was compared in high and low comprehension aphasics, brain damaged, and normal controls, by measuring latency and miss rate for recognition of six classes of associates, which were presented orally on tape. The ability to name each target was also examined as a function of the integrity of the subjects semantic field for that word. Low comprehension aphasics showed both quantitative and qualitative changes in semantic fields, while milder aphasics showed only mild quantitative impairment, as compared to controls. Both latency and miss rate measures indicated that failure to name a word is associated with reduced semantic field for that word. This result is interpreted as supporting the view that nameing is, in part, determined by the convergence of associations.

Improved naming after TMS treatments in a chronic, global aphasia patient – case report

We report improved ability to name pictures at 2 and 8 months after repetitive transcranial magnetic stimulation (rTMS) treatments to the pars triangularis portion of right Broca’s homologue in a 57 year-old woman with severe nonfluent/global aphasia (6.5 years post left basal ganglia bleed, subcortical lesion). TMS was applied at 1 Hz, 20 minutes a day, 10 days, over a two-week period. She received no speech therapy during the study. One year after her TMS treatments, she entered speech therapy with continued improvement. TMS may have modulated activity in the remaining left and right hemisphere neural network for naming.

Overt propositional speech in chronic nonfluent aphasia studied with the dynamic susceptibility contrast fMRI method.

This study examined activation levels in the left (L) supplementary motor area (SMA) and the right (R) SMA (separately), and activation in nine R perisylvian language homologues during overt, propositional speech in chronic nonfluent aphasia patients. Previous functional imaging studies with a variety of chronic aphasia patients have reported activation in these regions during different language tasks, however, overt propositional speech has not been examined. In the present research, four nonfluent aphasia patients were studied during overt elicited propositional speech at 4-9 years post-single L hemisphere stroke, which spared the SMA. The dynamic susceptibility contrast (DSC) method of functional MRI was used to calculate relative cerebral blood volume (relCBV) for cortical regions of interest (ROIs) during the first-pass bolus of gadolinium during two conditions: (1) pattern (silent viewing of checkerboard patterns) and (2) story (overt, elicited propositional speech describing sequential pictures, which formed a story). During the story condition, controls had significantly higher relCBV in L SMA than in R SMA; aphasics, however, had significantly higher relCBV in R SMA than in L SMA. During the pattern condition, no significant differences were observed between the L SMA and the R SMA for either controls or aphasics. In addition, aphasics had significantly higher relCBV in the R sensorimotor mouth during story than pattern. This R sensorimotor mouth relCBV was also significantly higher in aphasics than controls during story, and the two groups did not differ during pattern. The overall mean relCBV for the nine R perisylvian ROIs was significantly higher for aphasics than controls during both story and pattern. These results suggest that poor modulation, including possible over-activation of R sensorimotor mouth and other R perisylvian language homologues may underlie in part, the hesitant, poorly articulated, agrammatic speech associated with nonfluent aphasia.

Visual communication in aphasia

Abstract Aphasic patients who possessed little or no ability to communicate using natural language were taught a visual communication system (VIC). At issue on a theoretical level was wheter those cognitive operations entailed in natural language may persist in the face of destruction of natural language capacities. Of practical interest was whether severely aphasic patients could communicate effectively using an alternative symbol system. The program included two levels of communicative functions. At Level 1, patients carried out commands, answered questions, and described actions; at Level 2, patients employed the system spontaneously to express their desires and feelings. Of 8 patients given sufficient opportunity to master VIC, 5 completed Level 1, and 2 of these also satisfied the criteria for Level 2. Among these 5 patients, performance in VIC far surpassed performance on matching tasks in English; error rates were quite low; the pattern of errors was remarkably similar; an inverse correlation obtained between ability at English and ability at VIC. The evidence suggests that some severely aphasic patients can master the basics of an alternative symbol system. Moreover several indices suggest that the communicative consequences of the system are appreciated, and that at least some of the cognitive operations entailed in natural language persist despite severe aphasia.

Interaction between phonological and semantic factors in auditory comprehension

Abstract This study compared Wernickes and Brocas aphasic patients as to the influence of phonological vs semantic factors in their ability to make phonemic discriminations. Eight subjects of each diagnostic type participated in three experiments in which semantic processing played an increasing role. Experiment I was an auditory-auditory same-different match, Experiment II was an auditory-visual same-different match and Experiment III was an auditory vs visual multiple choice, introducing the possibility of either semantically or phonologically based errors. Wernickes aphasics were more impaired than Brocas at all levels, but their performance was disproportionately impaired as semantic mediation was introduced. Semantically based errors outnumbered phonologically based errors in Experiment III, which showed that just as semantic processing demand increases the risk of phonological error, so does phonological difficulty increase the risk of semantic error.

Cerebral Microembolism and Early Recurrent Cerebral or Retinal Ischemic Events

BACKGROUND AND PURPOSE We investigated whether cerebral microembolism as detected by transcranial Doppler ultrasonography (TCD) identifies patients at an increased risk for early, recurrent cerebral or retinal ischemic events. METHODS Records of consecutive patients examined during a 40-month period in the Neurovascular Laboratory were reviewed for the presence of cerebral microembolism. Of the original 302 patients, 229 with 310 arteries met inclusionary criteria. Follow-up information was obtained from the laboratorys database as well as the hospital records. Microembolus detection studies were performed on TC-2000 or TC-2020 instruments equipped with special software, and criteria established a priori were used for microembolus selection. TCD testing was performed a median interval of 9 days after the initial symptoms of cerebral ischemia. Severity of arterial stenosis was determined by cerebral angiography or noninvasive methods. RESULTS Microembolic signals were detected more frequently in symptomatic (40/140; 28.6%) than asymptomatic (21/170; 12.4%) arteries (P < .001). Ten recurrent ischemic events occurred during a median follow-up of 8 days after TCD examination, all in the territories of symptomatic arteries. Nine events occurred in the territories of microembolic signal positive arteries (9/61; 14.8%) and one in the territory of a microembolic signal-negative artery (1/249; 0.4%) (P < .00). No association was detected in the subgroup with known cardiac lesions. Microembolic signals were more frequent in arteries with lesions causing 70% or more stenosis or occlusion (26/99; 26.3%) than in those with a degree of stenosis less than 70% (17/126; 13.5%) (P = .016). CONCLUSIONS In this retrospective study, microembolic signals were more common in the territories of symptomatic arteries and particularly those with severely stenotic lesions. During a short follow-up, recurrent ischemic events were more common along the territories of arteries with TCD-detected microembolism and previous symptoms of cerebral or retinal ischemia.

Effects of Paying Physicians Based on their Relative Performance for Quality

BackgroundStudies examining the effectiveness of pay-for-performance programs to improve quality of care primarily have been confined to bonus-type arrangements that reward providers for performance above a predetermined threshold. No studies to date have evaluated programs placing providers at financial risk for performance relative to other participants in the program.ObjectiveThe objective of the study is to evaluate the impact of an incentive program conferring limited financial risk to primary care physicians.ParticipantsThere were 334 participating primary care physicians in Rochester, New York.DesignThe design of the study is a retrospective cohort study using pre/post analysis.MeasurementsThe measurements adhere to 4 diabetes performance measures between 1999 and 2004.ResultsWhile absolute performance levels increased across all measures immediately following implementation, there was no difference between the post- and pre-intervention trends indicating that the overall increase in performance was largely a result of secular trends. However, there was evidence of a modest 1-time improvement in physician adherence for eye examination that appeared attributable to the incentive program. For this measure, physicians improved their adherence rate on average by 7 percentage points in the year after implementation of the program.ConclusionsThis study demonstrates a modest effect in improving provider adherence to quality standards for a single measure of diabetes care during the early phase of a pay-for-performance program that placed physicians under limited financial risk. Further research is needed to determine the most effective incentive structures for achieving substantial gains in quality of care.

TMS suppression of right pars triangularis, but not pars opercularis, improves naming in aphasia

This study sought to discover if an optimum 1 cm(2) area in the non-damaged right hemisphere (RH) was present, which could temporarily improve naming in chronic, nonfluent aphasia patients when suppressed with repetitive transcranial magnetic stimulation (rTMS). Ten minutes of slow, 1Hz rTMS was applied to suppress different RH ROIs in eight aphasia cases. Picture naming and response time (RT) were examined before, and immediately after rTMS. In aphasia patients, suppression of right pars triangularis (PTr) led to significant increase in pictures named, and significant decrease in RT. Suppression of right pars opercularis (POp), however, led to significant increase in RT, but no change in number of pictures named. Eight normals named all pictures correctly; similar to aphasia patients, RT significantly decreased following rTMS to suppress right PTr, versus right POp. Differential effects following suppression of right PTr versus right POp suggest different functional roles for these regions.

Impact of the "polytrauma clinical triad" on sleep disturbance in a department of veterans affairs outpatient rehabilitation setting.

Lew HL, Pogoda TK, Hsu P-T, Cohen S, Amick MM, Baker E, Meterko M, Vanderploeg RD: Impact of the “polytrauma clinical triad” on sleep disturbance in a Department of Veterans Affairs outpatient rehabilitation setting. Objective:There is a high prevalence of Operation Enduring Freedom/Operation Iraqi Freedom veterans returning with the “polytrauma clinical triad” of pain, posttraumatic stress disorder, and traumatic brain injury. This study examined the effect of the polytrauma clinical triad on sleep disturbance, defined as difficulty falling or staying asleep, a common problem in Operation Enduring Freedom/Operation Iraqi Freedom veterans. Design:A chart review was conducted for 200 Operation Enduring Freedom/Operation Iraqi Freedom veterans evaluated at a polytrauma outpatient clinic. Data that were abstracted included a sleep disturbance severity index, diagnoses of posttraumatic stress disorder and traumatic brain injury, and reported problems of pain. Results:Sleep disturbance was highly prevalent (93.5%) in this sample, in which the majority of traumatic brain injury diagnoses were mild. In the multiple regression analysis, posttraumatic stress disorder, pain, the interaction of traumatic brain injury and posttraumatic stress disorder, and the interaction of posttraumatic stress disorder and pain significantly accounted for sleep disturbance. As a separate independent variable, traumatic brain injury was not associated with sleep disturbance. Conclusions:Our preliminary results showed that posttraumatic stress disorder and pain significantly contributed to sleep disturbance. When traumatic brain injury or pain coexisted with posttraumatic stress disorder, sleep problems worsened. In this clinical population, where the majority of traumatic brain injury diagnoses tend to be in the mild category, traumatic brain injury alone did not predict sleep disturbance. Through increased awareness of pain, posttraumatic stress disorder, and traumatic brain injury, clinicians can work collaboratively to maximize rehabilitation outcomes.

Psychometric assessment of the Neurobehavioral Symptom Inventory-22: the structure of persistent postconcussive symptoms following deployment-related mild traumatic brain injury among veterans.

ILD TRAUMATIC BRAIN INJURY (mTBI),also known as concussion, has been labeled asthe “signature injury” of Operations Enduring Free-dom/Iraqi Freedom (OEF/OIF). The persistent effectsof concussion are a focus of both research and reha-bilitation interventions, not only within the VeteransHealth Administration (VA), but in the general med-ical community.