RESEARCH OVERVIEW

We all experience moments when word-finding is disrupted (e.g., forgetting someone's name). But for people with acquired language disorders, word-finding, or anomia, can be a disruptive and emotionally taxing experience.

Our research focuses on the precision rehabilitation of anomia.

The Mental Lexicon and Anomia

Everybody has their own personal dictionary (or lexicon) in their memory. While most people think of a dictionary as a book on your shelf, we think about our mental dictionaries as an intricate web of connections between words, or a network.

In our mental lexicon network, words are connected to each based on shared linguistic similarity. For example, dog and cat would be connected based on shared semantic (or meaning) similarity because they share features like furry, tail, and pet. Another example would be the words mat and rat. They would be connected in the mental lexicon network because the words share similar phonology (or sounds).

By mapping the mental lexicon network, we can better understand how we store and retrieve words from memory and use them in everyday conversations. We can also understand how to add new connections (e.g., when learning a new language) or strengthen old connections (e.g., when faced with neurological disease or brain injury).

Everyone's mental lexicon is a little bit different. An important part of our research is understanding how to measure individuals' mental lexicon structure so that we can better personalize anomia treatment to each individual.

Anomia, or word retrieval difficulties, occurs from impairments in the process and/or structure of the mental lexicon.

For some neurodegenerative diseases, like Alzheimer's disease, there is a break down in semantic memory. This can result in losing words and connections between these words in the mental lexicon.

In contrast, for acquired aphasia due to stroke, there is often difficulty in accessing words in the network. That is, the words and connections are still there, but travelling along the connections is more difficult.

Modelling these differences in mental lexicon structure and processes is important for accurate diagnoses and precision rehabilitation of anomia.

Precision Rehabilaition of Anomia

Precision rehabilitation is designing intervention for individuals to maximize their outcomes. This requires deep knowledge about the causes of impairment, treatment designs, and patient goals. It is not enough to just provide an established anomia treatment to someone with anomia. Treatment must be tailored to the person and provided in the right environment with the right supports.

Precision rehabilitation is complex and requires new techniques and perspectives to drive the science behind precision rehabilitation. Our lab uses techniques from complex systems science to model precision rehabilitation of anomia.

For maximal patient outcomes, we must consider the systems involved in rehabilitation and how those systems interact over time. Specifically, we consider as systems:

the whole-person. For example, we must consider not just language abilities and the mental lexicon of individuals, but also psychosocial factors, like social support and mental health, and biological variables, like brain health. We need to understand the whole person in order to make appropriate treatment decisions.
treatment. For example, each treatment has a set of ingredients that come together to produce improved word retrieval abilities. We need to understand if, and how, these ingredients can be manipulated to accommodate individual needs and abilities.
healthcare. Even if we can provide an optimally designed treatment to a specific person, that person needs to be able to access this healthcare service. Factors like clinical settings, insurance coverage, and access to treatment supports are essential.

For a complete list of research publications, please check Dr. Castro's Google Scholar.

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