Aphasia Neuroplasticity Review

Sebastian & Kiran (2011)

Reference

AuthorsSebastian R, Kiran S.
TitleTask-modulated neural activation patterns in chronic stroke patients with aphasia
ReferenceAphasiology 2011; 25: 927-951
PMIDN/A
DOI10.1080/02687038.2011.557436

Participants

LanguageUS English
Inclusion criteria
Number of individuals with aphasia8
Number of control participants8
Were any of the participants included in any previous studies?No
Is age reported for patients and controls, and matched?Yes (range 40-79 years)
Is sex reported for patients and controls, and matched?No (males: 5; females: 3; control sex not stated, but reported to be matched)
Is handedness reported for patients and controls, and matched?Yes (right: 8; left: 0)
Is time post stroke onset reported and appropriate to the study design?Yes (mean 48.3 months, range 30-78 months)
To what extent is the nature of aphasia characterized?Comprehensive battery
Language evaluationWAB, BNT, portions of PALPA, PPT, CLQT
Aphasia severityAQ range 74.0-97.8
Aphasia type6 anomic, 2 recovered
First stroke only?Not stated
Stroke typeMixed etiologies
To what extent is the lesion distribution characterized?Individual lesions
Lesion extentRange 23-45 cc
Lesion locationL MCA
Participants notes

Imaging

ModalityfMRI
Is the study cross-sectional or longitudinal?Cross-sectional
If longitudinal, at what time point(s) were imaging data acquired?
If longitudinal, was there any intervention between the time points?
Is the scanner described?No (GE 3 Tesla; model not stated)
Is the timing of stimulus presentation and image acquisition clearly described and appropriate?No* (moderate limitation) (control events took place in the inter-trial interval between language events, and may have been systematically confounded in timing; the total number of functional images acquired is not stated)
Design typeEvent-related
Total images acquirednot stated
Are the imaging acquisition parameters, including coverage, adequately described and appropriate?Yes (whole brain)
Is preprocessing and intrasubject coregistration adequately described and appropriate?Yes
Is first level model fitting adequately described and appropriate?No (only correct trials are included but it is not stated how incorrect trials were modeled; in general, it is not stated whether the control events were modeled at all)
Is intersubject normalization adequately described and appropriate?Yes
Imaging notes

Conditions

Are the conditions clearly described?Yes
ConditionResponse typeRepetitionsAll groups could do?All individuals could do?
picture namingWord (overt)60YesYes
viewing scrambled images and saying "pass"Word (overt)60UnknownUnknown
semantic decisionButton press48YesYes
visual decisionButton press48UnknownUnknown
Conditions notes

Contrasts

Are the contrasts clearly described?Yes

Contrast 1: picture naming (correct trials) vs viewing scrambled images and saying "pass"

Language conditionPicture naming (correct trials)
Control conditionViewing scrambled images and saying "pass"
Are the conditions matched for visual demands?Yes
Are the conditions matched for auditory demands?Yes
Are the conditions matched for motor demands?Yes
Are the conditions matched for cognitive/executive demands?No
Is accuracy matched between the language and control tasks for all relevant groups?Unknown, not reported
Is reaction time matched between the language and control tasks for all relevant groups?Unknown, not reported
Behavioral data notesAccuracy/RT not reported for control task
Are control data reported in this paper or another that is referenced?Somewhat
Does the contrast selectively activate plausible relevant language regions in the control group?Somewhat
Are activations lateralized in the control data?No
Control activation notesReporting is selective, but appears mostly bilateral with slight L-lateralization of language areas
Contrast notes

Contrast 2: semantic decision (correct trials) vs visual decision

Language conditionSemantic decision (correct trials)
Control conditionVisual decision
Are the conditions matched for visual demands?Yes
Are the conditions matched for auditory demands?Yes
Are the conditions matched for motor demands?Yes
Are the conditions matched for cognitive/executive demands?Yes
Is accuracy matched between the language and control tasks for all relevant groups?Unknown, not reported
Is reaction time matched between the language and control tasks for all relevant groups?Unknown, not reported
Behavioral data notesAccuracy/RT not reported for control task
Are control data reported in this paper or another that is referenced?Somewhat
Does the contrast selectively activate plausible relevant language regions in the control group?Somewhat
Are activations lateralized in the control data?Yes
Control activation notesClearly lateralized frontal activation, but very modest temporal activation
Contrast notes

Analyses

Are the analyses clearly described?Yes

ROI analysis 1

First level contrastPicture naming (correct trials) vs viewing scrambled images and saying "pass"
Analysis classCross-sectional correlation with language or other measure
Group(s)Aphasia
CovariateLesion volume
Is the second level contrast valid in terms of the group(s), time point(s), and measures involved?Yes
Is accuracy matched across the second level contrast?Yes, correct trials only
Is reaction time matched across the second level contrast?Unknown, not reported
Behavioral data notes
Type of analysisRegions of interest (ROI)
ROI typeMixed
How many ROIs are there?4
What are the ROI(s)?(1) L IFG (oper/tri); (2) L posterior perisylvian (pSTG, pMTG, AG, SMG); (3) R IFG (oper/tri); (4) R posterior perisylvian (pSTG, pMTG, AG, SMG); (5) language network LI
How are the ROI(s) defined?Harvard–Oxford atlas
Correction for multiple comparisonsNo correction
Statistical details
Findings↑ R supramarginal gyrus
↑ R angular gyrus
↑ R posterior STG/STS/MTG
↓ LI (language network)
Findings notesLarger lesions were associated with more R posterior perisylvian activation

ROI analysis 2

First level contrastSemantic decision (correct trials) vs visual decision
Analysis classCross-sectional correlation with language or other measure
Group(s)Aphasia
CovariateLesion volume
Is the second level contrast valid in terms of the group(s), time point(s), and measures involved?Yes
Is accuracy matched across the second level contrast?Yes, correct trials only
Is reaction time matched across the second level contrast?Unknown, not reported
Behavioral data notes
Type of analysisRegions of interest (ROI)
ROI typeMixed
How many ROIs are there?4
What are the ROI(s)?(1) L IFG (oper/tri); (2) L posterior perisylvian (pSTG, pMTG, AG, SMG); (3) R IFG (oper/tri); (4) R posterior perisylvian (pSTG, pMTG, AG, SMG); (5) language network LI
How are the ROI(s) defined?Harvard–Oxford atlas
Correction for multiple comparisonsNo correction
Statistical details
FindingsNone
Findings notes

Notes

Excluded analyses(1) individual patient analyses; (2) comparisons between the two language tasks