Important advances in neuroscience and clinical aphasiology have led to a greater understanding of brain networks and linguistic function after stroke. With these advances has come clarity - and acknowledged complexity. The substantial individual variability in aphasia profile and treatment response has motivated research of lesion characterizations, linguistic performance features, and intervention ingredients. Some personal variables, such as age, sex, time since stroke, and level of education, are frequently included as potential contributors to rehabilitation. Other personal variables have been examined to a lesser degree, though these variables may influence treatment outcomes more than we once believed. In this issue of Topics in Language Disorders, we focus on several personal factors presently understudied in the aphasia rehabilitation literature that may contribute to treatment response or overall rehabilitation outcomes.

The stress hormone cortisol has been hypothesized as a potential contributor to rehabilitation. Gravier and colleagues examined cortisol levels in individuals with aphasia participating in an intensive intervention and reported on the complexity of this biomarker and ongoing questions about its role in predicting treatment outcomes.

Although cognitive-linguistic variables have received attention in aphasia research, fewer studies have been conducted on nonlinguistic cognitive variables. Diedrichs and colleagues conducted a review of the research literature on the influence of nonlinguistic cognitive variables on treatment outcomes. Hunting Pompon and Mach also reviewed the stroke and aphasia literature to identify characterizations of resilience-psychological, cognitive, behavioral-and how this state/process has been considered relative to rehabilitation. Weatherill and colleagues sought answers from the literature about the role of motivation as a component of behavioral intervention, a little examined facet of aphasia rehabilitation. Their conclusions include a call for research and development of a motivation measurement, in part, to examine its impact on aphasia rehabilitation.

Some personal factors are measured through patient report of perceptions or experiences. In this issue's final article, Engelhoven and colleagues present a study of the readability and accessibility of patient-reported outcome measures (PROMs) used with individuals with aphasia, consolidate the evidence-based criteria available to date for optimal PROM development, and emphasize the importance of valid measurement of personal perspectives and experiences.

There are a number of other personal factors that may contribute to treatment response-depression, race/ethnicity, socioeconomics, and related access to rehabilitation, and neurological and other comorbidities among them. I am hopeful that these important variables will be a focus of aphasiology in the coming years, especially to determine the magnitude of their influence on treatment response and rehabilitation outcomes overall.

-Rebecca Hunting Pompon, PhD

Issue Editor