Aphasia: Language De-Acquisition

Approximately five years ago, my grandfather developed a bit of a stutter.  What was strange about it was its inconstancy: he would speak fluently without interruption but occasionally stop suddenly at a word, usually a noun, and struggle to get it out.  Sometimes he would have to talk around the word before being able to pronounce it, or someone in my family would end up feeding it to him.  The difficulty became more pronounced as time went on and slowly it became clear that he was losing his ability to use language.  Although he was able to read, write, and understand fluently, words were disappearing from his accessible vocabulary one by one. 

My grandfather was soon diagnosed with the Logopenic variant of Primary Progressive Aphasia, a form of degeneration in the frontal and temporal lobes of the brain that specifically affects the ability to access language.  As the name indicates, Primary Progressive Aphasia (PPA) is a progressive disease that worsens gradually over time.  In general, it begins with a difficulty in accessing specific and often common words and progresses to difficulties in reading, writing, and ultimately an overall deterioration of memory.  With the Logopenic variant (LvPPA), the hardest-hit area is word-retrieval.  This exhibits itself in a slowed rate of speech, talking around words, mispronunciations, and substitutions of words and sounds.  However, the comprehension of words is typically preserved and reading and writing are retained longer than speech.  LvPPA can also exhibit itself through memory loss, which is shown in an increasing inability to comprehend complex or lengthy verbal information and difficulties with phrase repetition.  Such memory loss often results in disorientation of place and time and is indicative of a strong connection between LvPPA and Alzheimer’s Disease.   

When learning about language acquisition in class, I could not help but notice significant parallels, albeit reversed, between a child’s gradual acquisition of language and my grandfather’s gradual loss of it.  In other words, he lost his language usage in the same order in which a child acquires it. This is true overall (he lost speech before reading and writing just as children speak before becoming literate) and in the smaller details of the disease’s progression.  His decline began with the loss of common and useful nouns such as “table,” “store,” and “cat.”  Simple nouns like these are foundational to a person’s lexicon and are some of the first a child learns when acquiring language.   Interestingly, more abstract or complex nouns that are learned later in the process were preserved for far longer than simple object nouns.  In addition, substitutions of similar sounds within words—“w” for “r” or “g” for “k”—would creep into his speech.  Mistakes like these are also common in the early stages of language acquisition and are quickly corrected.  In this phase of PPA’s progression, my grandfather would speak in syntactically and grammatically perfect sentences, just with mispronunciations and inaccessibility of nouns within the structures. Verbs, pronouns, prepositions, and articles were generally preserved as well.  Similarly, learning how to use these parts of speech to combine words into syntactically-correct phrases is one of the final stages of language acquisition. 

Soon after this phase, however, his speech began to deteriorate much faster.  Without much of the lexicon remaining, his frustration and co-occurring memory loss interrupted his ability to express his ideas through fluent speech and he began to lose verbs and various other parts of speech.  The loss of connecting words caused his grasp of syntactic structures to crumble, completing the progression of his aphasia.  He can now no longer read nor write, but evidence in his attempts to speak show that he still comprehends speech; he produces full, purposeful bouts of incomprehensible gibberish in response to others’ conversation, and looks expectantly at his audience as if he had spoken coherently.  In essence, he has returned to the initial stage of speech: babbling.

For discussion: Why do you think the progression of PPA so closely mirrors the stages of language acquisition?  How might PPA affect a multilingual speaker differently?  What connections exist between language usage and neurological disorders such as PPA and Alzheimer’s?