Aphasia Neuroplasticity Review

Meinzer et al. (2008)

Reference

AuthorsMeinzer M, Flaisch T, Breitenstein C, Wienbruch C, Elbert T, Rockstroh B
TitleFunctional re-recruitment of dysfunctional brain areas predicts language recovery in chronic aphasia
ReferenceNeuroImage 2008; 39: 2038-2046
PMID18096407
DOI10.1016/j.neuroimage.2007.10.008

Participants

LanguageGerman
Inclusion criteria
Number of individuals with aphasia11
Number of control participants0
Were any of the participants included in any previous studies?No
Is age reported for patients and controls, and matched?Yes (median 51.0 years, range 19-66 years)
Is sex reported for patients and controls, and matched?Yes (males: 7; females: 4)
Is handedness reported for patients and controls, and matched?Yes (right: 11; left: 0)
Is time post stroke onset reported and appropriate to the study design?Yes (median 32 months; range 6-480 months)
To what extent is the nature of aphasia characterized?Comprehensive battery
Language evaluationAAT, study-specific picture naming test with 150 items
Aphasia severity6 moderate, 4 mild, 1 severe
Aphasia type7 Broca's, 2 Wernicke's, 1 global, 1 unclassified
First stroke only?Not stated
Stroke typeMixed etiologies
To what extent is the lesion distribution characterized?Lesion overlay
Lesion extentRange 31.0-236.0 cc
Lesion locationL
Participants notes

Imaging

ModalityfMRI
Is the study cross-sectional or longitudinal?Longitudinal—chronic treatment
If longitudinal, at what time point(s) were imaging data acquired?T1: pre-treatment/chronic; T2: post-treatment, ~2 weeks later
If longitudinal, was there any intervention between the time points?CIAT, 3 hours/day, 5 days/week, 2 weeks
Is the scanner described?Yes (Philips Intera 1.5 Tesla)
Is the timing of stimulus presentation and image acquisition clearly described and appropriate?Yes
Design typeBlock
Total images acquired160
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?Yes
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 naming (trained items)Word (overt)8YesNo
picture naming (untrained items)Word (overt)8YesNo
restNone16N/AN/A
Conditions notesOne participant was < 10% on trained and untrained items at T1

Contrasts

Are the contrasts clearly described?Yes

Contrast 1: picture naming (trained items) vs rest

Language conditionPicture naming (trained items)
Control conditionRest
Are the conditions matched for visual demands?No
Are the conditions matched for auditory demands?No
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?No
Does the contrast selectively activate plausible relevant language regions in the control group?Unknown
Are activations lateralized in the control data?Unknown
Control activation notes
Contrast notes

Contrast 2: picture naming (untrained items) vs rest

Language conditionPicture naming (untrained items)
Control conditionRest
Are the conditions matched for visual demands?No
Are the conditions matched for auditory demands?No
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?No
Does the contrast selectively activate plausible relevant language regions in the control group?Unknown
Are activations lateralized in the control data?Unknown
Control activation notes
Contrast notes

Analyses

Are the analyses clearly described?No* (moderate limitation) (see specific limitation(s) below)

ROI analysis 1

First level contrastPicture naming (trained items) vs rest
Analysis classLongitudinal correlation with language or other measure
Group(s)Aphasia T2 vs T1
CovariateΔ picture naming (trained items)
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 notesPicture naming score (trained items) increased from 51.7 ± 24.8 to 78.8 ± 22.1, which was statistically significant (p < 0.0001)
Type of analysisRegions of interest (ROI)
ROI typeOther
How many ROIs are there?4
What are the ROI(s)?(1) perilesional area of slow wave activity determined with MEG; (2) right hemisphere homotopic to lesion; (3) right hemisphere homotopic to slow wave area; (4) remainder of left hemisphere; for one patient, maximal slow wave activity was in the right hemisphere and it is not clear how this was handled
How are the ROI(s) defined?The dependent measure was the number of voxels in each ROI exceeding certain thresholds that differed across subjects depending on their strength of activation; it appears that increases and decreases may have been summed, though the description is hard to follow
Correction for multiple comparisonsNo correction
Statistical details2 of the 11 patients were classified as outliers and excluded from analyses, however no plots are provided to justify their status as outliers
FindingsOther
Findings notesImproved picture naming of trained items was correlated with increased signal in 3 of the 4 ROIs, the exception being the right hemisphere ROI homotopic to the slow wave area; after removing the two outliers, only the correlation in the left hemisphere area of slow wave activity remained significant

ROI analysis 2

First level contrastPicture naming (untrained items) vs rest
Analysis classLongitudinal correlation with language or other measure
Group(s)Aphasia T2 vs T1
CovariateΔ picture naming (untrained items)
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 notesPicture naming score (untrained items) increased from 54.0 ± 24.3 to 70.5 ± 26.7, which was statistically significant (p= 0.002)
Type of analysisRegions of interest (ROI)
ROI typeOther
How many ROIs are there?4
What are the ROI(s)?(1) perilesional area of slow wave activity determined with MEG; (2) right hemisphere homotopic to lesion; (3) right hemisphere homotopic to slow wave area; (4) remainder of left hemisphere; for one patient, maximal slow wave activity was in the right hemisphere and it is not clear how this was handled
How are the ROI(s) defined?The dependent measure was the number of voxels in each ROI exceeding certain thresholds that differed across subjects depending on their strength of activation; it appears that increases and decreases may have been summed, though the description is hard to follow
Correction for multiple comparisonsNo correction
Statistical details2 of the 11 patients were classified as outliers and excluded from analyses, however no plots are provided to justify their status as outliers
FindingsOther
Findings notesImproved picture naming of untrained items was correlated with increased signal in all 4 ROIs; after removing the two outliers, none of the correlations remained significant

Notes

Excluded analysesAdditional analyses correlating functional changes in the "delta ROI" with ROI extent, initial severity, duration of aphasia, overall speech activity, since limited detail is provided and only one ROI is reported