BACKGROUNDBACKGROUND

Lesion Characteristics Related to Naming Improvement in Aphasic Stroke Patients: The Role of Anterior Cortex and the Basal Ganglia

R.B. Parkinson1,3, Y.L. Chang1, A.M. Raymer2 & B. Crosson1

1 University of Florida and the Malcom Randall VA RR&D Brain Rehabilitation Research Center; Gainesville, FL2 Old Dominion University, Norfolk, VA 3 Birmingham VA Medical Center, Birmingham, AL

Naming Treatment • Probe task: Pictures of objects and/or actions were presented as black and white line drawings for subjects to name• Treatment involved the therapist either cueing the subject with semantic or phonological information or training the subject to pair the target word with a gesture •Subjects were administered naming probes prior to treatment to ensure a stable baseline naming performance on the treatment word set• Prior to each treatment session, subjects were administered that same probe to assess for treatment improvement• Each treatment lasted 10 sessions, with 3-5 sessions per week

Lesion Analysis Scan types: 7 MRI (3-D T1 weighted images), 7 CT films, 1 MRI film (FLAIR) Angle of 3-D MRI scans were adjusted to match the typical angle of CT scans (approximately 15 degrees to the canthomeatal line) using ANALYZE 5.0 Borders for ROI’s were defined and identified according to anatomical landmarks established using the 15 degree slices of the Matsui and Hirano (1978) brain atlas

29 cortical and subcortical ROIs were assessed by 2 independent raters ROIs were rated for extent of lesion using a rating schema adapted from Naeser et al.,1998 (see below) Composite ratings for anterior cortical, posterior cortical, and basal ganglia were obtained by summing individual ROI ratings

Statistical Analysis Correlations were carried out between naming measures and composite ROI ratings (anterior, posterior, and basal ganglia) Naming measures included:

Pretreatment naming: defined as performance on the Boston Naming Test (BNT) and Action Naming Test (ANT) Naming improvement: calculated as the range corrected gain scores for naming probes

• The left basal ganglia may play an important role in inhibiting neural noise originating from damaged left frontal language areas, which may facilitate cortical reorganization of language function to other areas. When the left basal ganglia is damaged, it may be less able to facilitate cortical reorganization in this way (see Crosson et al., 2005).

• In some chronic aphasic subjects with moderate anterior damage, anterior regions may produce neural noise that interferes with cortical reorganization of naming. In subjects with larger anterior lesions, this source of noise may have been eliminated, allowing for more efficient reorganization.

• Since in this group of patients lesion extent in these two areas appears to affect naming in opposite directions, controlling for the effects of one is needed to more clearly observe the effects of the other.

Several previous studies have offered important insights into the role of the basal ganglia and the anterior language cortex in the reorganization of language in chronic aphasic stroke patients, and have led up to a recent hypothesis put forth by Crosson et al. (2005).• Brunner et al. (1982) found that:

• Basal ganglia lesions alone generally resulted in only transient aphasia• Cortical plus basal ganglia lesions resulted in more severe, longer lasting aphasia than cortical lesions alone

• Kim et al. (2002) found that in an fMRI language task with aphasic stroke patients:

• Those with only left frontal lesions showed unilateral right frontal activation• Those with left frontal plus basal ganglia lesions showed bilateral frontal activation

• Crosson et al. (2003) found that in non-aphasic subjects, the right basal ganglia appears to suppress right frontal areas during normal language production

Crosson et al. (2005) Hypothesis• An intact left basal ganglia allows for suppression of compromised left hemisphere language areas and a more successful shift of language production to right hemisphere areas• A lesioned left basal ganglia will not suppress left hemisphere “noise” which interferes with reorganization of language production

Brunner, R. J., et al. (1982). Brain and Language, 16, 281-299.Crosson, B., et al. (2005). Journal of Cognitive Neuroscience, 17(3), 392-406. Crosson, B., et al. (2003). JINS 9, 1061-1077. Kim, Y. H., et al. (2002). Yonsei Medical Journal, 43(4), 441-445. Matsui, T. & Hirano, A. (1978). An atlas of the human brain for computerized tomography.Naeser, M. A. et al. (1998). Archives of Neurology, 55, 1438-1448.

Correlations

Pretreatment Treatment Improvement

Partial Correlations#

Pretreatment Treatment Improvement

*p<.05, **p < .01# - Partial correlations shown here for both Anterior and

Posterior are controlling for basal ganglia lesion extent; partial correlations for Basal Ganglia are controlling for Anterior lesion extent

NOTE: While negative correlations indicate that smaller lesions are correlated with better naming, positive correlations indicate that larger lesions are correlated with better naming.

Basal Ganglia

Anterior Posterior

Object -.623** .730** -.350

Action -.750** .740** -.470*

Basal Ganglia

Anterior Posterior

Object -.749** .858** -.373

Action -.785** .821** -.256

Basal Ganglia

Anterior Posterior

Object -.056 .532* -.336

Action -.263 .363 -.538*

Basal Ganglia

Anterior Posterior

Object .075 .634* -.296

Action -.219 .437 -.295

Rating system

0 = no lesion

1 = equivocal lesion

2 = small, patchy or partial lesion

2.5 = patchy, less than half of the area has lesion

3 = half of area has lesion

4 = more than half of area has solid lesion

5 = total area has solid lesion

Participants 15 chronic left hemisphere stroke patients who underwent naming treatment for objects and/or actions.

* range-corrected gain scores

N Mean SD Min Max

Age 15 65.2 10.6 49 81

Education 15 13.4 2.0 10 18

Months since stroke

15 30.7 35.6 5 128

BNT (% correct) 15 .199 .179 0 .483

ANT (% correct) 15 .320 .232 .032 .694

Object Naming Improvement*

13 .284 .256 -.02 .83

Action Naming Improvement*

12 .197 .255 -.04 .77

Template adapted from Matsui and Hirano, 1978.

METHODSMETHODS

METHODS (cont.)METHODS (cont.) RESULTSRESULTS

DISCUSSION and CONCLUSIONSDISCUSSION and CONCLUSIONS

REFERENCESREFERENCES