Aphasia Neuroplasticity Review

Allendorfer et al. (2012)

Reference

AuthorsAllendorfer JB, Kissela BM, Holland SK, Szaflarski JP
TitleDifferent patterns of language activation in post-stroke aphasia are detected by overt and covert versions of the verb generation fMRI task
ReferenceMed Sci Monit 2012; 18: CR135-147
PMID22367124
DOI10.12659/msm.882518

Participants

LanguageUS English
Inclusion criteriaMCA; moderate-severe aphasia; mRS <= 3
Number of individuals with aphasia16
Number of control participants32
Were any of the participants included in any previous studies?Yes ("part of a larger ongoing study", may overlap with other studies from this group)
Is age reported for patients and controls, and matched?Yes (mean 54.4 ± 9.5 years, range 38-78 years)
Is sex reported for patients and controls, and matched?Yes (males: 9; females: 7)
Is handedness reported for patients and controls, and matched?Yes (right: 16; left: 0)
Is time post stroke onset reported and appropriate to the study design?Yes (mean 3.7 ± 3.5 years, range 0.5-11.4 years)
To what extent is the nature of aphasia characterized?Severity and type
Language evaluationTT, PPVT, BNT, semantic and phonemic fluency, complex ideation subtest of BDAE
Aphasia severityModerate-severe; TT mean 25.5 ± 11.3; unclear how to reconcile moderate-severe severity with mostly anomic aphasia
Aphasia typeMostly anomic with some non-fluent
First stroke only?Not stated
Stroke typeIschemic only
To what extent is the lesion distribution characterized?Individual lesions
Lesion extentRange 2.8-248.9 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 (Phillips 3 Tesla; model not stated)
Is the timing of stimulus presentation and image acquisition clearly described and appropriate?Yes
Design typeMixed
Total images acquired435
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 (no description of HRF model, which is important given sparse sampling design)
Is intersubject normalization adequately described and appropriate?No (lesion impact not addressed)
Imaging notessparse sampling

Conditions

Are the conditions clearly described?Yes
ConditionResponse typeRepetitionsAll groups could do?All individuals could do?
verb generation (overt, event-related)Multiple words (overt)15YesUnknown
verb generation (covert, event-related)Multiple words (covert)15UnknownUnknown
noun repetition (event-related)Multiple words (overt)15YesUnknown
verb generation (covert, block)Multiple words (covert)10UnknownUnknown
finger tapping (block)Other10UnknownUnknown
Conditions notesGiven the means and standard deviations presented, it is likely that some patients could not perform some tasks; post-scan recognition tests not considered to quantify performance

Contrasts

Are the contrasts clearly described?Yes

Contrast 1: verb generation (covert, block) vs finger tapping (block)

Language conditionVerb generation (covert, block)
Control conditionFinger tapping (block)
Are the conditions matched for visual demands?Yes
Are the conditions matched for auditory demands?Yes
Are the conditions matched for motor demands?No
Are the conditions matched for cognitive/executive demands?No
Is accuracy matched between the language and control tasks for all relevant groups?N/A, tasks not comparable
Is reaction time matched between the language and control tasks for all relevant groups?N/A, tasks not comparable
Behavioral data notes
Are control data reported in this paper or another that is referenced?Yes
Does the contrast selectively activate plausible relevant language regions in the control group?Yes
Are activations lateralized in the control data?Yes
Control activation notesStrongly lateralized frontal and temporal activation
Contrast notes

Contrast 2: verb generation (overt, event-related) vs noun repetition (event-related)

Language conditionVerb generation (overt, event-related)
Control conditionNoun repetition (event-related)
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?Appear mismatched
Is reaction time matched between the language and control tasks for all relevant groups?Unknown, not reported
Behavioral data notes
Are control data reported in this paper or another that is referenced?Yes
Does the contrast selectively activate plausible relevant language regions in the control group?Somewhat
Are activations lateralized in the control data?Somewhat
Control activation notesSomewhat L-lateralized frontal, temporal and parietal activations, but also extensive midline activation
Contrast notes

Contrast 3: verb generation (overt, event-related) vs verb generation (covert, event-related)

Language conditionVerb generation (overt, event-related)
Control conditionVerb generation (covert, event-related)
Are the conditions matched for visual demands?Yes
Are the conditions matched for auditory demands?No
Are the conditions matched for motor demands?No
Are the conditions matched for cognitive/executive demands?Yes
Is accuracy matched between the language and control tasks for all relevant groups?N/A, tasks not comparable
Is reaction time matched between the language and control tasks for all relevant groups?N/A, tasks not comparable
Behavioral data notes
Are control data reported in this paper or another that is referenced?Yes
Does the contrast selectively activate plausible relevant language regions in the control group?Somewhat
Are activations lateralized in the control data?N/A
Control activation notesBilateral speech motor activations, but also extensive midline activation
Contrast notes

Analyses

Are the analyses clearly described?Yes

ROI analysis 1

First level contrastVerb generation (covert, block) vs finger tapping (block)
Analysis classCross-sectional aphasia vs control
Group(s)Aphasia vs control
Covariate
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?Unknown, not reported
Is reaction time matched across the second level contrast?Unknown, not reported
Behavioral data notes
Type of analysisRegions of interest (ROI)
ROI typeLaterality indi(ces)
How many ROIs are there?2
What are the ROI(s)?(1) frontal LI; (2) temporal LI
How are the ROI(s) defined?
Correction for multiple comparisonsNo correction
Statistical details
Findings↓ LI (temporal)
Findings notes

ROI analysis 2

First level contrastVerb generation (overt, event-related) vs noun repetition (event-related)
Analysis classCross-sectional aphasia vs control
Group(s)Aphasia vs control
Covariate
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?No, different
Is reaction time matched across the second level contrast?Unknown, not reported
Behavioral data notesPatients less accurate and produced less responses on both conditions, but the difference between groups was greater for verb generation
Type of analysisRegions of interest (ROI)
ROI typeLaterality indi(ces)
How many ROIs are there?2
What are the ROI(s)?(1) frontal LI; (2) temporal LI
How are the ROI(s) defined?
Correction for multiple comparisonsNo correction
Statistical details
Findings↓ LI (frontal)
Findings notes

ROI analysis 3

First level contrastVerb generation (overt, event-related) vs verb generation (covert, event-related)
Analysis classCross-sectional aphasia vs control
Group(s)Aphasia vs control
Covariate
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?No, different
Is reaction time matched across the second level contrast?Unknown, not reported
Behavioral data notesOvert performance differed, so covert performance probably did too
Type of analysisRegions of interest (ROI)
ROI typeLaterality indi(ces)
How many ROIs are there?2
What are the ROI(s)?(1) frontal LI; (2) temporal LI
How are the ROI(s) defined?
Correction for multiple comparisonsNo correction
Statistical details
FindingsNone
Findings notesLack of lateralization in controls makes this analysis difficult to interpret

ROI analysis 4

First level contrastVerb generation (overt, event-related) vs noun repetition (event-related)
Analysis classCross-sectional correlation with language or other measure
Group(s)Aphasia
CovariateOvert verb generation accuracy
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?Accuracy is covariate
Is reaction time matched across the second level contrast?Unknown, not reported
Behavioral data notes
Type of analysisRegions of interest (ROI)
ROI typeFunctional
How many ROIs are there?3
What are the ROI(s)?(1) L MTG; (2) L SFG/CG; (3) left MFG
How are the ROI(s) defined?Regions activated by the contrast of overt verb generation vs noun repetition in patients
Correction for multiple comparisonsNo correction
Statistical details
Findings↑ L dorsolateral prefrontal cortex
↑ L SMA/medial prefrontal
Findings notes

ROI analysis 5

First level contrastVerb generation (overt, event-related) vs verb generation (covert, event-related)
Analysis classCross-sectional correlation with language or other measure
Group(s)Aphasia
CovariateOvert verb generation accuracy
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?Accuracy is covariate
Is reaction time matched across the second level contrast?Unknown, not reported
Behavioral data notes
Type of analysisRegions of interest (ROI)
ROI typeFunctional
How many ROIs are there?2
What are the ROI(s)?(1) R insula/IFG; (2) R STG
How are the ROI(s) defined?Prominent R hemisphere activations for the contrast of overt and covert verb generation in patients
Correction for multiple comparisonsNo correction
Statistical details
FindingsNone
Findings notes

Notes

Excluded analysesAnalysis of LI distribution (left/right/bilateral) yielded similar results