MONDAY, 9 MARCH 2020
Imagine having a conversation with a friend about something on your mind when suddenly you can't find the words for what you want to say. Similar to forgetting where you saved a file on your computer, you know exactly what you’re looking for, but you just can’t remember how to access it. Anomia, or the inability to recall words, is the defining feature of aphasia, an acquired language disorder commonly resulting from left hemisphere stroke.
Different forms of aphasia vary in the extent to which different language skills are affected: fluent, or receptive aphasias mainly impair a person’s language comprehension, while nonfluent, or expressive aphasias mainly impair a person’s language production. Different forms of aphasia also vary in the forms of errors they cause in each individual. These can be semantic (related to meaning), phonemic (difficulty with pronunciation), or neologistic (using made up words), to name a few.
Aphasia is inability, or impaired ability, to understand or produce written or spoken language, as a result of brain damage. It is most commonly caused by stroke.
Despite these variations, all aphasias selectively affect a person’s ability to functionally communicate with others. Since language is such an important aspect of our lives - allowing us to navigate the world and connect with others - the loss of language can be devastating for people affected by aphasia. Impairments in the ability to express ourselves can lead to feelings of isolation and disconnection, in addition to impacting our sense of identity. “When you can’t find a word,” writes stroke survivor Lauren Marks about her experience with aphasia, “it’s like you are locked out of your own house”.
The brain’s plasticity often allows the neural pathways supporting language to be recovered through repeated exposure and practice at home along with speech therapy. However, communication is highly complex. Language production requires the ability to retrieve words and use them to form sentences, while language comprehension requires understanding the meanings of words, phrases, and sentences. Which aspects of language should be targeted to best support individuals and provide them the tools they need to express themselves? What strategies should be used to support learning and recall over time? Recent research in Speech and Language Pathology has focused on finding effective approaches for treating specific language deficits in individuals with aphasia and enabling them to communicate with others more effectively in their everyday lives.
Since words are the basic units of meaning in language, and because the primary deficit of aphasia is anomia, many treatments have focused on supporting effective word retrieval. Semantic Feature Analysis (SFA) is a treatment based on the lexical retrieval theory that once a concept is activated, related semantic features are also activated, resulting in spreading activation to other concepts with shared semantic features. If you hear the word “apple”, for example, you might also think of “fruit”, “red” and “banana”. SFA involves asking individuals to name features of a target object. How big or small is the object? What color is it? Where can you find it? Is it something you eat? What does it do? By generating features related to the target word’s function, use, appearance, and related properties, people engage in a deeper semantic processing that facilitates word retrieval over time. This can sometimes carry-over to facilitate word finding of new words that haven’t previously been targeted during treatment.
The use of SFA also teaches individuals a helpful strategy for overcoming breakdowns in communication when they are unable to recall a specific word through what is known as circumlocution, the use of descriptions to communicate an idea. If you can’t think of the word “tiger”, for example, you might say “a big cat with stripes that roars”. Although circumlocution is generally an inefficient means of communicating something, it can provide an alternative way of overcoming moments of communication blocks when people feel stuck and unable to express themselves. If the inability to remember a word locks you out of your own house, circumlocution is like finding a different means inside through a basement door or window. It also emphasizes the importance of persistence in the recovery of language abilities, reminding people who struggle with verbal expression that their determined efforts allow communication to still be possible even during moments of difficulty, and that the imperfect use of words is better than not using any words at all.
Effective language production depends not only on the ability to retrieve words, but to combine them appropriately to form sentences by following the language’s grammatical rules. Expressing relationships between entities, such as cause and effect or changes of state, involves following correct syntax in addition to using the right words. (Consider the difference between ‘The dog chases the cat’ and ‘The cat chases the dog’, or why the sentence ‘The teeth brush the dentist’ does not make sense). Expressing such relationships by increased lexical retrieval of verbs and improved argument structure is the main focus of an approach known as Verb Network Strengthening Treatment (VNeST).
In this treatment, individuals are asked to generate agents and patients for a given verb, creating verb phrases that follow the subject-verb-object sentence structure in English. For example, given the verb ‘measure’, different agents and patients can be used to create sentences such as ‘The baker measures the flour’ and ‘The carpenter measures the wood’. Verbs prime semantically related words (for example, the verb ‘sweep’ can readily trigger the noun ‘dust’). Individuals then expand on their verb phrases by answering different wh- questions (e.g. Why was the baker measuring the flour? Where was the carpenter measuring wood?). This is thought to further activate the semantic network related to that verb, helping people improve their word finding and sentence structure.
SFA and VNeST are just two examples of a multitude and variety of aphasia treatments that are currently being researched and implemented in various clinical settings to help people with aphasia in their rehabilitation. Other approaches have facilitated language recovery through emphasizing different modalities, such as incorporating spelling to support reading and writing, and practicing pronunciation of words to improve speech. Just as every house has a different lock requiring its own key, each individual will require a personalised strategy. Hopefully, by using a combination of approaches, speech and language pathologists can equip individuals with aphasia with the tools required to communicate with others and more comfortably navigate the complex fabric of language that permeates the world.
Anna Serrichio is a Speech and Language Pathologist at NYU Langone Hospital. Artwork by Rita Sasidharan.