Aphasia Study Guide

📖 Core Concepts Aphasia – loss of ability to understand or produce spoken/written language due to damage in left‑hemisphere language areas; not a motor or hearing problem. Fluent vs. Non‑fluent – Fluent: normal speech rate but poor content (e.g., Wernicke’s). Non‑fluent: halting, effortful speech but relatively good comprehension (e.g., Broca’s). Primary Progressive Aphasia (PPA) – a neurodegenerative form where language declines gradually while other cognition stays relatively intact. Lesion size & location – larger lesions and posterior (temporal) damage generally cause more severe deficits; anterior lesions often produce non‑fluent types. Therapy dosage – 20–50 total hours, distributed as 2–5 h/week (4–5 days) yields the best functional gains; higher intensity (≈15 h/week) can boost outcomes but raises dropout risk. 📌 Must Remember Prevalence: 30 % of stroke survivors develop aphasia; 0.1–0.4 % of the general population in developed countries. Major causes: Stroke (ischemic/hemorrhagic) > head trauma > tumors > neurodegenerative disease. Boston Classification (key subtypes) Broca (expressive) – non‑fluent, good comprehension, poor repetition. Wernicke (receptive) – fluent, poor comprehension, frequent paraphasias, poor repetition. Conduction – fluent, good comprehension, impaired repetition. Anomic – intact fluency/comprehension, word‑finding difficulty. Global – severe deficits in all language modalities. Prognostic indicators – early therapy (<1 mo), younger age (<55 yr), smaller lesion, higher baseline language ability. Evidence‑based techniques – Semantic Feature Analysis, Melodic Intonation Therapy, intensive, task‑specific SLT. 🔄 Key Processes Clinical Assessment Workflow Take history → Identify cause (stroke, TBI, tumor, PPA). Perform bedside language screen (naming, repetition, comprehension, reading, writing). Order MRI to locate lesion (left frontal/temporal). Classify aphasia subtype (Boston or PPA variant). Set therapy goals based on severity, cognitive profile, and patient priorities. Therapy Dose‑Response Cycle Initial Phase (0–6 mo): high‑frequency SLT (≥3 sessions/week) → rapid spontaneous recovery + therapy‑driven gains. Chronic Phase (>6 mo): maintain intensive practice (≥2 h/week) + home/tele‑practice → incremental improvements, especially for naming. Semantic Feature Analysis (SFA) Steps Patient names target word → therapist prompts semantic attributes (category, function, physical properties, etc.). Patient generates related words → strengthens semantic network → improves word retrieval. 🔍 Key Comparisons Broca vs. Wernicke Speech: effortful, short phrases vs. fluent, jargon‑filled. Comprehension: relatively preserved vs. severely impaired. Repetition: poor vs. poor (both), but Wernicke’s repetition especially deficient. Conduction vs. Transcortical Motor Repetition: impaired vs. preserved. Speech fluency: fluent vs. non‑fluent. Anomic vs. Global Naming: impaired in both, but global has widespread receptive/expression deficits; anomic has intact comprehension and fluency. Early vs. Late Therapy Initiation Early: larger effect size, requires less intensity for comparable gains. Late: needs higher intensity, gains slower but still possible. ⚠️ Common Misunderstandings Aphasia ≠ Dysarthria – aphasia is a language‑cognitive disorder; dysarthria is muscle weakness affecting articulation. “Fluent” does not mean “intact” – fluent aphasics may produce many words but convey little meaning. All aphasia recovers fully – only 10 % achieve full recovery; many retain residual deficits despite therapy. Higher intensity always better – excessive dosage can cause fatigue and dropout; balance intensity with patient stamina. 🧠 Mental Models / Intuition “Traffic Light” model: Red (non‑fluent) – speech flow stopped, need “push” (effortful drills, Melodic Intonation). Yellow (fluent but confused) – speech moves but direction wrong; target semantics (SFA). Green (repetition intact) – pathway (arcuate fasciculus) OK; focus on comprehension or naming. “Lesion‑Location → Symptom” map: Anterior (Broca) → motor planning → non‑fluent; Posterior (Wernicke) → auditory‑semantic processing → fluent‑nonsensical. 🚩 Exceptions & Edge Cases Sign‑language aphasia – language deficits can appear in sign production/comprehension while oral speech is unaffected. PPA variants – may mimic stroke‑related subtypes but progress slowly; semantic dementia can preserve fluency despite loss of meaning. Large lesions with mild aphasia – possible when right‑hemisphere compensates or when critical language nodes are spared. 📍 When to Use Which Therapy Technique Selection Non‑fluent (Broca, PPA‑nonfluent) → Melodic Intonation Therapy, articulatory‑kinematic drills. Fluent with word‑finding problems (Wernicke, Anomic, Logopenic) → Semantic Feature Analysis, cueing hierarchies. Impaired repetition (Conduction, Transcortical sensory) → Repetition drills combined with auditory‐feedback training. Imaging Modality – MRI preferred for precise lesion mapping; use when planning subtype‑specific therapy. 👀 Patterns to Recognize Paraphasia type → lesion hint: phonemic errors → arcuate fasciculus; semantic errors → temporal lobe. Preserved formulaic language (e.g., singing) → suggests right‑hemisphere involvement; useful for melodic therapies. Rapid improvement within first 6 mo → likely spontaneous recovery plus early therapy; plateau later may indicate chronic stage. 🗂️ Exam Traps “Fluent aphasia = good comprehension” – false; Wernicke’s is fluent but comprehension is poor. “All aphasics need intensive therapy” – false; intensity must be matched to stamina and chronicity. “Lesion size directly predicts severity” – misleading; size matters but location and individual neuroplasticity create wide variability. “Anomic aphasia has poor comprehension” – incorrect; comprehension is typically intact. “Melodic Intonation Therapy works for fluent aphasia” – limited; best evidence is for non‑fluent (Broca‑type) speech.