Aphasia Neuroplasticity Review

Cardebat et al. (2003)

Reference

AuthorsCardebat D, Démonet JF, De Boissezon X, Marie N, Marié RM, Lambert J, Baron JC, Puel M
TitleBehavioral and neurofunctional changes over time in healthy and aphasic subjects: a PET Language Activation Study
ReferenceStroke 2003; 34: 2900-2906
PMID14615626
DOI10.1161/01.str.0000099965.99393.83

Participants

LanguageFrench
Inclusion criteriaNo severe aphasia; no leukoaraiosis
Number of individuals with aphasia8
Number of control participants6
Were any of the participants included in any previous studies?No
Is age reported for patients and controls, and matched?Yes (mean 58.4 ± 11.9 years, range 37-73 years)
Is sex reported for patients and controls, and matched?Yes (males: 7; females: 1)
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?No* (moderate limitation) (T1: 58 ± 35 days, range 11-113 days; T2: 11.7 ± 1.6 months, range 320-460 days; T1 varies considerably from early to late subacute)
To what extent is the nature of aphasia characterized?Not at all
Language evaluationNot stated
Aphasia severityNot stated
Aphasia typeT1: some prominent symptoms are listed for each patient; T2: not stated
First stroke only?Yes
Stroke typeMixed etiologies
To what extent is the lesion distribution characterized?Individual lesions
Lesion extentNot stated
Lesion location4 L subcortical, 2 L prerolandic, 2 L postrolandic
Participants notes

Imaging

ModalityPET (rCBF)
Is the study cross-sectional or longitudinal?Longitudinal—recovery
If longitudinal, at what time point(s) were imaging data acquired?T1: 58 ± 35 days, range 11-113 days; T2: 11.7 ± 1.6 months, range 320-460 days; T1 varies considerably from early to late subacute
If longitudinal, was there any intervention between the time points?Not stated
Is the scanner described?Yes (Siemens ECAT HR+)
Is the timing of stimulus presentation and image acquisition clearly described and appropriate?Yes
Design typePET
Total images acquired6
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?No (lesion impact not addressed)
Imaging notes

Conditions

Are the conditions clearly described?Yes
ConditionResponse typeRepetitionsAll groups could do?All individuals could do?
word generationWord (overt)4YesUnknown
restNone2N/AN/A
Conditions notesParticipants were asked to generate words that were semantically related to binaurally presented stimuli; 2 runs involved nouns and 2 involved verbs

Contrasts

Are the contrasts clearly described?Yes

Contrast 1: word generation vs rest

Language conditionWord generation
Control conditionRest
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?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?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 notesBilateral fronto-temporal and some other regions per text
Contrast notes

Analyses

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

Voxelwise analysis 1

First level contrastWord generation vs rest
Analysis classLongitudinal change in aphasia
Group(s)Aphasia T2 vs T1
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 notes
Type of analysisVoxelwise
Search volumeWhole brain
Correction for multiple comparisonsClusterwise correction based on arbitrary cluster extent
SoftwareSPM99
Voxelwise p.05
Cluster extent50 voxels (size not stated)
Statistical detailsNature of inclusive masks unclear
Findings↑ L dorsolateral prefrontal cortex
↑ L SMA/medial prefrontal
↑ L somato-motor
↑ L posterior STG/STS/MTG
↑ L cerebellum
↑ R IFG pars opercularis
↑ R dorsolateral prefrontal cortex
↑ R SMA/medial prefrontal
↑ R somato-motor
↑ R posterior STG/STS/MTG
↑ R cerebellum
Findings notesBased on Figure 2

Voxelwise analysis 2

First level contrastWord generation vs rest
Analysis classLongitudinal correlation with language or other measure
Group(s)Aphasia T2 vs T1
CovariateΔ word 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 analysisVoxelwise
Search volumeWhole brain
Correction for multiple comparisonsClusterwise correction based on arbitrary cluster extent
SoftwareSPM99
Voxelwise p.001
Cluster extent100 voxels (size not stated)
Statistical detailsNature of inclusive masks unclear
Findings↑ L posterior STG/STS/MTG
↑ R posterior STG/STS/MTG
↑ R cerebellum
↓ L occipital
↓ L hippocampus/MTL
↓ R dorsolateral prefrontal cortex
↓ R occipital
Findings notes

Notes

Excluded analysesAphasia vs control SPM analyses at each time point, because they are not reported in sufficient detail to determine activated regions