Intrahemispheric Perfusion in Chronic Stroke-Induced Aphasia
Table 1
Studies of perfusion in chronic aphasia.
Study
Sample size ()
Time since stroke
Diagnosis
Treatment protocol
MRI method
Task
Key findings
Love et al., 2002
1
16 years
Anomia, difficulty in reading
—
PASL
Resting state
(i) Hypoperfusion in L angular gyrus, L supramarginal gyrus; neither region infarcted
Peck et al., 2004
3
8–48 months
Nonfluent aphasia
2 with intention treatment; 1 with attention treatment
BOLD TTP
Category member generation
(i) From pre- to posttreatment, average difference across patients in TTP between R auditory cortex and R motor cortex decreased, corresponding to shortened posttreatment response times, and approached the average value for controls
Fridriksson et al., 2006
1
18 months
Aphasia (incl. moderate anomia)
—
PWI/BOLD
Overt picture naming
(i) Delayed TTP in resting state PWI in LH versus RH (ii) Abnormal HRF in activated areas during naming
Bonakdarpour et al., 2007
5
>2 years
Agrammatic aphasia
—
BOLD TTP
Lexical decision
(i) Increased TTP in L perisylvian cortex (3 of 5 individuals) relative to healthy controls (ii) No differences in R perisylvian or L or R occipital cortex
Brumm et al., 2010
3
2–11 years
Expressive aphasia
—
PASL
Resting state
(i) Hypoperfusion in L penumbra (2 voxels); noninfarcted regions of L hemisphere
Thompson et al., 2010
6
6–146 months
Agrammatic aphasia
Treatment of Underlying Forms (TUF)
PASL
Resting state
(i) Regions with upregulated BOLD response (auditory sentence-picture verification task) following treatment showed faster TTP (ii) After treatment, 4 patients decreased TTP in L angular gyrus; 3 decreased TTP in L superior parietal cortex; 4 decreased TTP in R superior parietal cortex
Richardson et al., 2011
17
4–246 months
Aphasia (not specified)
—
PASL
Resting state
(i) Hypoperfusion in L penumbra (8 mm); noninfarcted regions of L hemisphere (ii) Larger lesion correlated with reduced perfusion
(i) Pretreatment perfusion levels in residual language network regions, that is, not infarcted and not perilesional (15 mm), predicted posttreatment improvement in picture naming (ii) Pretreatment perfusion levels in infarcted and perilesional tissue did not predict posttreatment improvement
Bonakdarpour et al., 2015
5
6–96 months
2 Broca’s aphasia; 3 anomia
—
BOLD TTP
Overt picture naming
(i) Increased TTP in L hemisphere naming regions relative to healthy controls (ii) No difference in percent signal change
PASL: pulsed arterial spin labeling; PWI: perfusion weighted imaging; TTP: time to peak (of the hemodynamic response function (HRF)); SMA: supplementary motor area.
