Word Retrieval in the Wild: An Ecological Momentary Assessment Pilot Study in People With Post-Stroke Aphasia

BACKGROUND AND TRANSLATIONAL SIGNIFICANCE Background Approximately 15 million individuals worldwide, including 795,000 Americans, suffer a new stroke each year. Aphasia, a disorder characterized by receptive and/or expressive language deficits, affects approximately 30% of stroke survivors and is one of the most devastating post-stroke conditions. Aphasia is a heterogenous disorder, yet anomia (i.e., impaired word retrieval) is a persistent, ubiquitous impairment present in all people with aphasia (PWA). Neurotypical individuals occasionally experience anomia during "tip-of-the-tongue" moments: frustrating instances when someone knows what they want to say but the word itself eludes them. For the two million Americans currently living with aphasia, word retrieval difficulties are far more severe and pervade all communication attempts. Anomia severity ranges between PWA, from mild difficulties such as delayed retrieval of low frequency words (e.g., amulet) to severe difficulty retrieving the names of even common objects (e.g., bed). Yet, regardless of severity, a hallmark of post-stroke anomia is inconsistent word retrieval across attempts for a given word. For PWA, the ability to access words can change day-to-day and even minute-to-minute, resulting in diminished motivation to participate in conversations, disengagement from social interactions, and reduced quality of life.

Per psycholinguistic models of lexical access, naming is a two-step process that involves retrieval of the target's meaning from the semantic system and word form (speech sounds) from the phonological system. Naming failures in PWA result in errors that are related to a target word in meaning (e.g., "carrot" for bean), word form (e.g., "fean" for bean), both meaning and form (e.g., "green" for bean), or neither (e.g., "pencil" for bean; "I know it but I can't say it" for bean) due to insufficient activation of the target meaning/form representations or overactivation of incorrect representations. Due to this noisy system, lexical access is often delayed in PWA, even when the correct word is eventually retrieved. Naming accuracy, response times, and error types provide meaningful information regarding the locus of naming impairment and a patient's recovery capacity. The investigators found that the number of phonological and unrelated errors produced during early post-stroke stages predicted longitudinal changes in naming and global language skills in left hemisphere stroke survivors. Naming errors and the integrity of underlying semantic and phonological systems can also guide language treatment planning. As such, accurate assessment of naming is critical for aphasia care.

In clinical practice, speech-language pathologists (SLPs) typically assess naming deficits through a single administration of a test in a quiet clinic room in a 1:1 interaction between the SLP and patient. Yet, given the variability in word retrieval, a one-time assessment cannot accurately capture the true nature and extent of a patient's anomia. Moreover, unlike a controlled, contrived clinical environment, word retrieval in the real world usually occurs while an individual performs other daily tasks, often in distracting, noisy environments and with many other people present. The added cognitive load of multi-tasking and suppressing external distractors adds to an already noisy lexical system, thereby increasing the chance of delayed or failed word retrieval. Traditional SLP assessment cannot capture the realities of real-world anomia, but the investigators argue that ecological momentary assessment (EMA) can.

EMA is a widely used method in health research to capture longitudinal self-reported behaviors or states of interest (e.g., physical activity, depression, diet) in daily life. In traditional EMA, an electronic device prompts a participant to answer a set of questions (usually via button press) many times a day over time. Answering several questions at a time is time intensive, and thus, a key disadvantage of traditional EMA is interruption burden. In contrast, micro-interaction-based EMA (µEMA) reduces each prompt to a single question that can be answered in ~3-5s, allowing for many more questions interspersed over time. The investigators' pilot studies suggest that even with an interruption rate eight times more than traditional EMA, µEMA has higher response rates and lower perceived burden than traditional EMA. Furthermore, µEMA yields temporally dense in-situ measures, making it an ideal tool for capturing the variability of anomia in the daily lives of PWA. One caveat is that an anomia µEMA/EMA protocol would necessitate recording verbal responses, yet traditional EMA and µEMA protocols to date have only required nonverbal responses via a button press or screen tap. The feasibility of capturing high-quality audio responses in a µEMA or traditional EMA protocol is unknown.

Moreover, despite the increasing use of technology-based assessments and therapy platforms for aphasia, neither electronically delivered EMA nor µEMA has been tested in PWA. In fact, based on a review from 2020, only seven studies have used EMA to study stroke recovery and none targeted language impairments. A central question is whether stroke survivors with aphasia can adhere to electronically delivered traditional EMA or µEMA anomia protocols. Prior research regarding tablet and computer-based platforms for aphasia indicates that PWA with better visuospatial attention and executive functions are better able to learn how to navigate a novel iPad application. Evidence suggests that SLP support is associated with greater adherence to a computerized therapy program for PWA and that patients' perceived engagement in the computer program is related to opportunities for practice, their ability to use the technology, and their motivation. An important step towards broader implementation of EMA and/or µEMA in aphasia is determining PWA's adherence to such protocols and which patient-specific factors are associated with protocol adherence.