Associations among depression, demographic variables, and language impairments in chronic post-stroke aphasia

INTRODUCTION

Depression may influence treatment participation and outcomes of people with post-stroke aphasia, yet its prevalence and associated characteristics in aphasia are poorly understood. Using retrospective data from an overarching experimental study, we examined depressive symptoms and their relationship to demographic and language characteristics in people with chronic aphasia. As a secondary objective, we compared prevalence of depressive symptoms among the overarching study's included and excluded participants.

METHODS

We examined retrospective data from 121 individuals with chronic aphasia including depression scale scores, demographic information (sex, age, time post onset of stroke, education, race/ethnicity, and Veteran status), and scores on assessments of general and modality-specific language impairments.

RESULTS

Approximately 50% of participants reported symptoms indicative of depressive disorders: 23% indicative of major depression and 27% indicative of mild depression. Sex (males) and comparatively younger age emerged as statistically significant variables associated with depressive symptoms; naming ability was minimally associated with depressive symptoms. Time post onset of stroke, education level, race/ethnicity, Veteran status, and aphasia severity were not significantly associated with depressive symptoms. Depression-scale scores were significantly higher for individuals excluded from the overarching study compared to those who were included.

CONCLUSIONS

The rate of depressive disorders in this sample was higher than rates of depression reported in the general stroke literature. Participant sex, age, and naming ability emerged as factors associated with depressive symptoms, though these links appear complex, especially given variable reports from prior research. Importantly, depressive symptoms do not appear to diminish over time for individuals with chronic aphasia. Given these results and the relatively limited documentation of depression in aphasia literature, depression remains a pressing concern for aphasia research and routine clinical care.

Articulatory Gain Predicts Motor Cortex and Subthalamic Nucleus Activity During Speech

Speaking precisely is important for effective verbal communication, and articulatory gain is one component of speech motor control that contributes to achieving this goal. Given that the basal ganglia have been proposed to regulate the speed and size of limb movement, that is, movement gain, we explored the basal ganglia contribution to articulatory gain, through local field potentials (LFP) recorded simultaneously from the subthalamic nucleus (STN), precentral gyrus, and postcentral gyrus. During STN deep brain stimulation implantation for Parkinson's disease, participants read aloud consonant-vowel-consonant syllables. Articulatory gain was indirectly assessed using the F2 Ratio, an acoustic measurement of the second formant frequency of/i/vowels divided by/u/vowels. Mixed effects models demonstrated that the F2 Ratio correlated with alpha and theta activity in the precentral gyrus and STN. No correlations were observed for the postcentral gyrus. Functional connectivity analysis revealed that higher phase locking values for beta activity between the STN and precentral gyrus were correlated with lower F2 Ratios, suggesting that higher beta synchrony impairs articulatory precision. Effects were not related to disease severity. These data suggest that articulatory gain is encoded within the basal ganglia-cortical loop.