Poster D22, Wednesday, August 21, 2019, 5:15 – 7:00 pm, Restaurant Hall
Longitudinal Recovery of Auditory Comprehension following Stroke
Juliana Baldo1, Timothy Herron1, Brian Curran1, Sandy Lwi1, Krista Parker1, Maria Ivanova1,2, Nina Dronkers1,2;1Veterans Affairs Northern California Health Care System, 2University of California, Berkeley
Introduction: Aphasia recovery research has largely focused on changes during the first year following stroke, but it has been suggested that clinical progress continues to take place after this time. Also, recovery studies have typically focused on speech and language broadly, with few studies focusing on the recovery of auditory comprehension. To address these gaps, we examined the demographic and neuroanatomical variables associated with natural recovery of auditory comprehension deficits following stroke during the first year and beyond. Methods: We retrospectively analyzed data from 46 stroke patients in our database who met the following criteria: 1) single, left hemisphere stroke; 2) right-handed; 3) native English speaker; 4) language testing at two or more time points with no intervening treatment; 5) available CT or MRI lesion reconstruction; and 6) no previous neurologic or severe psychiatric history. Auditory comprehension scores were taken from the Western Aphasia Battery (WAB), which includes both single-word and sentence-level auditory comprehension subtests. Patients’ average auditory comprehension scores ranged from very impaired to mildly impaired (range = 18-90% correct; mean = 69% correct). The sample included patients with Broca’s aphasia, Wernicke’s aphasia, global aphasia, conduction aphasia, and anomic aphasia. A mixed effects model using a single, fixed recovery slope was used to test for the best auditory comprehension recovery time transformation by finding the best fit to the longitudinal patient data, indicated by the lowest Bayesian Information Criterion (BIC) score under the model. To identify the neural predictors of recovery, Voxel-based Lesion Symptom Mapping (VLSM) was used to determine brain regions associated with improvements in patients’ comprehension scores over time. Results: Curves involved in survival analysis across time such as the Log-Logistic, the Lomax, and the Exponential-Log provided the best fit transformations for the longitudinal recovery data and showed that auditory comprehension scores often improved substantially in both year 1 and year 2 of stroke recovery, and to a lesser extent in subsequent years. With respect to predictor variables, age was a significant factor in auditory comprehension recovery, but none of the following variables were significantly related: gender, education, and lesion volume. The VLSM analysis using the best Log-Logistic recovery transformation identified a significant region of left superior temporal cortex and underlying white matter that was associated with poor recovery of auditory comprehension. Conclusions: Findings from this study in 46 patients with aphasia confirm suggestions that spontaneous language improvement continues well beyond the first year following stroke, and that the degree of improvement is affected by age and the presence of lesions in left superior temporal cortex and adjacent white matter.
Themes: Disorders: Acquired, Meaning: Lexical Semantics
Method: Behavioral