Predicting recovery in acute poststroke aphasia

Abstract

Objective: Many stroke patients show remarkable recovery of language after initial severe impairment, but it is difficult to predict which patients will show good recovery. We aimed to identify patient and lesion characteristics that together predict the best naming outcome in 4 studies.

Methods: We report 2 longitudinal studies that identified 2 variables at onset that were strongly associated with good recovery of naming (the most common residual deficit in aphasia) in the first 6 months after stroke: damage to left posterior superior temporal gyrus (pSTG) and/or superior longitudinal fasciculus/arcuate fasciculus (SLF/AF), and selective serotonin reuptake inhibitor (SSRI) use. We then tested these variables in 2 independent cohorts of chronic left hemisphere stroke patients, using chi-square tests and multivariate logistic regression for dichotomous outcomes and t tests for continuous outcomes.

Results: Lesion load in left pSTG and SLF/AF was associated with poorer naming outcome. Preservation of these areas and use of SSRIs were associated with naming recovery, independent of lesion volume, time since stroke, and depression. Patients with damage to these critical areas showed better naming outcome if they took SSRIs for 3 months after stroke. Those with preservation of these critical areas achieved good recovery of naming regardless of SSRI use.

Interpretation: Lesion load in left pSTG and SLF/AF at onset predicts later naming performance. Although based on a small number of patients, our preliminary results suggest outcome might be modulated by SSRIs, but these associations need to be confirmed in a larger randomized controlled trial. Ann Neurol 2018;83:612-622.

Figure 1

Panel A. Areas (in red) where damage was significantly associated with impaired object naming in the first longitudinal study. The brain template is partially transparent so lesion locations associated with naming performance can be viewed from different orientations. Red represents areas where more damage is significantly associated with lower accuracy in object naming. Note that the Right orientation image in the top right panel shows results in the left hemisphere as viewed “through” the right hemisphere.” Panel B. Lesion overlay map showing the number of patients with damage to each area. Color denotes number of individuals who had at least partial damage to the given parcel. The lower threshold (N>8) for the map is set so that only regions where at least 8 patients had damage are included. Slices correspond to −24, −16, −8, 0, 8, 16, 24, 32, 40 and 50mm in MNI coordinates.

Figure 2

Scatterplot showing the relationship between potential recovery on the BNTsf and achieved recovery on the BNTsf.

Figure 3

Panel A. Areas where damage was significantly associated with impaired object naming in chronic post-stroke aphasia. The brain template is partially transparent so lesion locations associated with naming performance can be viewed from different orientations. Red represents areas where more damage is significantly associated with lower accuracy in object naming, and yellow represents areas where more damage is associated with higher accuracy in picture naming. Note that the Right orientation image in the top right panel shows results in the left hemisphere as viewed “through” the right hemisphere.” The three parcels where the correlation was significant (p<0.001) were left superior temporal gyrus (STG) (−0.63), left posterior STG (−0.53) and left superior longitudinal fasciculus (SLF) (−0.65) on the JHU-MNI atlas Panel B. JHU-MNI Atlas Demarcation of Parcels of Interest (where percentage of damaged voxels was significantly associated with error rate in naming) Green=left STG; Red=left posterior STG; Blue=SLF Panel C. Lesion overlay map for the 159 patients included in the chronic study. The lower threshold (N>10) for the map is set so that only regions where at least 10 patients had damage are included. Coordinates are the same as Figure 1B. Panel D. The arcuate fasciculus from the Catani atlas (https://www.natbrainlab.co.uk/atlas-maps)

Figure 4

Divergent outcomes at 12 months post-stroke in two 56 year old right handed men with damage to left pSTG/SLF. Top panel. FLAIR images of initially aphasic man who achieved the highest quartile of recovery of naming (98.3% correct) after taking an SSRI continuously for three months after stroke. Lower panel: FLAIR images of an initially aphasic man of the same age who failed to achieve the highest quartile of recovery of object naming at the same time point after stroke. He did not take an SSRI (or any antidepressant) after the stroke, and was not depressed