Animal analogue studies show that damaged adult brains reorganize to accommodate compromised functions. In the human arena, functional magnetic resonance imaging (fMRI) and other functional neuroimaging techniques have been used to study reorganization of language substrates in aphasia. The resulting controversy regarding whether the right or the left hemisphere supports language recovery and treatment progress must be reframed. A more appropriate question is when left-hemisphere mechanisms and when right-hemisphere mechanisms support recovery of language functions. Small lesions generally lead to good recoveries supported by left-hemisphere mechanisms. However, when too much language eloquent cortex is damaged, right-hemisphere structures may provide the better substrate for recovery of language. Some studies suggest that recovery is particularly supported by homologues of damaged left-hemisphere structures. Evidence also suggests that under some circumstances, activity in both the left and right hemispheres can interfere with recovery of function. Further research will be needed to address these issues. However, daunting methodological problems must be managed to maximize the yield of future fMRI research in aphasia, especially in the area of language production. In this review, we cover six challenges for imaging language functions in aphasia with fMRI, with an emphasis on language production: (1) selection of a baseline task, (2) structure of language production trials, (3) mitigation of motion-related artifacts, (4) the use of stimulus onset versus response onset in fMRI analyses, (5) use of trials with correct responses and errors in analyses, and (6) reliability and stability of fMRI images across sessions. However, this list of methodological challenges is not exhaustive. Once methodology is advanced, knowledge from conceptually driven fMRI studies can be used to develop theoretically driven, mechanism-based treatments that will result in more effective therapy and to identify the best patient candidates for specific treatments. While the promise of fMRI in the study of aphasia is great, there is much work to be done before this technique will be a useful clinical tool.
Financial capacity is a complex instrumental activity of daily living critical to independent functioning of older adults and sensitive to impairment in patients with amnestic mild cognitive impairment (MCI) and Alzheimer's disease (AD). However, little is known about the neurocognitive basis of fi nancial impairment in dementia. We developed cognitive models of fi nancial capacity in cognitively healthy older adults ( n = 85) and patients with MCI ( n = 113) and mild AD ( n = 43). All participants were administered the Financial Capacity Instrument (FCI) and a neuropsychological test battery. Univariate correlation and multiple regression procedures were used to develop cognitive models of overall FCI performance across groups. The control model ( R 2 = .38) comprised (in order of entry) written arithmetic skills, delayed story recall, and simple visuomotor sequencing. The MCI model ( R 2 = .69) comprised written arithmetic skills, visuomotor sequencing and set alternation, and race. The AD model ( R 2 = .65) comprised written arithmetic skills, simple visuomotor sequencing, and immediate story recall. Written arithmetic skills (WRAT-3 Arithmetic) was the primary predictor across models, accounting for 27% (control model), 46% (AD model), and 55% (MCI model) of variance. Executive function and verbal memory were secondary model predictors. The results offer insight into the cognitive basis of fi nancial capacity across the dementia spectrum of cognitive aging, MCI, and AD. ( JINS , 2009, 15 , 258-267 .)
Task-correlated motion artifacts that occur during functional magnetic resonance imaging can be mistaken for brain activity. In this work, a new selective detrending method for reduction of artifacts associated with task-correlated motion (TCM) during speech in event-related functional magnetic resonance imaging is introduced and demonstrated in an overt word generation paradigm. The performance of this new method is compared with that of three existing methods for reducing artifacts because of TCM: (1) motion parameter regression, (2) ignoring images during speech, and (3) detrending time course datasets of signal components related to TCM (deduced from artifact corrupted voxels). The selective detrending method outperforms the other three methods in reducing TCM artifacts and in retaining blood oxygenation level dependent signal.
Chronic pain and cognitive difficulties are common secondary to traumatic brain injury (TBI); however, given the vast heterogeneity in TBI presentation, no empirically supported treatments specific to TBI exist. This case demonstrates the effectiveness of an empirically informed multimodal treatment, in which treatment components were selected based on the patient’s individual symptoms and delivered in a manner cognizant of the patient’s cognitive profile. Treatment incorporated components of cognitive behavioral therapy, physical intervention, mindfulness, sleep hygiene, distress tolerance, and cognitive rehabilitation. Pain, sleep, and therapy-related activities were logged daily. Treatment progress was further measured with the Beck Depression Inventory–II, Beck Anxiety Inventory, Satisfaction With Life Scale, and Insomnia Severity Index. The patient reported a significant reduction in pain (average pain rating reduced from 8.5-9 to 6.90 on the numerical rating scale [NRS]) and reported experiencing his least painful day in “years” (i.e., pain rating of 3). The patient reported improvements in mood and sleep, increased engagement in physical/other pleasant activities, and improved academic performance. The patient is currently not pursuing opioids or surgical intervention for pain. This case demonstrates the importance of utilization of neuropsychological data in the identification of treatment goals, appropriate treatment selection, and implementation of suitable techniques. This approach can provide neurologically atypical individuals with interventions that better address their symptom presentation and maximize prognosis.
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