Language and Speech Disorders
Introduction
Language and speech disorders are high-yield topics for the MCCQE1, commonly appearing under Neurology and Internal Medicine. Understanding the distinction between language (the cognitive process of forming and understanding communication) and speech (the motor act of articulation) is fundamental to clinical localization and management.
In the Canadian healthcare context, recognizing these disorders promptly is crucial for activating stroke protocols (“Code Stroke”) and initiating multidisciplinary rehabilitation involving Speech-Language Pathologists (SLPs).
CanMEDS Communicator Role
Assessing a patient with a language disorder requires advanced communication skills. Physicians must utilize non-verbal cues, written aids, and collateral history to ensure accurate data acquisition and patient safety.
Definitions and Distinctions
It is vital to differentiate between the following terms for the MCCQE1:
- Aphasia (Dysphasia): An acquired disorder of language content, form, or use due to brain damage (usually left hemisphere). It affects speaking, listening, reading, and writing.
- Dysarthria: A motor speech disorder resulting from neurological injury of the motor component of the motor-speech system. Comprehension and grammar are intact; clarity of speech is affected.
- Dysphonia: A disorder of voice production (laryngeal pathology) affecting pitch, loudness, or quality.
MCCQE1 Tip: If a patient can write a correct sentence but cannot speak clearly, they likely have dysarthria or apraxia, not aphasia. If the writing is also impaired (agraphia), suspect aphasia.
Neuroanatomy of Language
For the vast majority of right-handed individuals (and roughly 70% of left-handed individuals), the left hemisphere is dominant for language.
| Area | Location | Function | Vascular Supply |
|---|---|---|---|
| Broca’s Area | Posterior Inferior Frontal Gyrus | Motor programming of speech (Fluency) | Superior division of Left MCA |
| Wernicke’s Area | Posterior Superior Temporal Gyrus | Comprehension of language | Inferior division of Left MCA |
| Arcuate Fasciculus | White matter tract | Connects Broca’s and Wernicke’s (Repetition) | Left MCA territory |
Aphasia Syndromes
Aphasia is classically categorized based on Fluency, Comprehension, and Repetition.
Non-Fluent Aphasias
Non-Fluent Aphasias
Speech is effortful, slow, and halting. Phrase length is short (<5 words).
1. Broca’s Aphasia (Expressive Aphasia)
- Lesion: Left posterior inferior frontal gyrus.
- Features: Agrammatic speech, frustration (patient is aware of deficit), intact comprehension.
- Associated signs: Right hemiparesis (face/arm > leg) due to proximity to the primary motor cortex.
2. Transcortical Motor Aphasia
- Lesion: Anterior or superior to Broca’s area (watershed infarct).
- Features: Similar to Broca’s but repetition is preserved.
3. Global Aphasia
- Lesion: Extensive damage to left hemisphere (Broca’s, Wernicke’s, and Arcuate Fasciculus).
- Features: Severe impairment in fluency, comprehension, and repetition. Mute or stereotyped utterances.
Differential Diagnosis Table
| Type | Fluency | Comprehension | Repetition | Naming |
|---|---|---|---|---|
| Broca’s | Impaired | Intact | Impaired | Impaired |
| Wernicke’s | Intact | Impaired | Impaired | Impaired |
| Conduction | Intact | Intact | Impaired | Impaired |
| Global | Impaired | Impaired | Impaired | Impaired |
| Transcortical Motor | Impaired | Intact | Intact | Impaired |
| Transcortical Sensory | Intact | Impaired | Intact | Impaired |
Dysarthria
Dysarthria is a disorder of articulation. The content of the language is normal.
Common Classifications
- Spastic (UMN): “Strained-strangled” voice. Seen in pseudobulbar palsy.
- Flaccid (LMN): Breathy, nasal voice. Seen in bulbar palsy (e.g., ALS, Myasthenia Gravis).
- Ataxic (Cerebellar): “Scanning speech,” irregular volume and breakdown of rhythm. Seen in Multiple Sclerosis, cerebellar stroke.
- Hypokinetic: Monotone, low volume. Classic for Parkinson’s Disease.
Clinical Approach to Language Disorders
When approaching a patient with speech difficulties on the MCCQE1, follow a structured assessment.
Step 1: Assess Fluency
Listen to spontaneous speech. Is it effortless? Is the phrase length normal (>5 words)?
- Yes: Fluent.
- No: Non-fluent.
Step 2: Assess Comprehension
Give simple commands that do not require non-verbal cues.
- “Close your eyes.”
- “Point to the ceiling, then the floor.” (Multi-step commands).
Step 3: Assess Repetition
Ask the patient to repeat phrases of increasing complexity.
- “No ifs, ands, or buts.”
- Note: This tests the integrity of the perisylvian language arc (Broca’s - Arcuate Fasciculus - Wernicke’s).
Step 4: Assess Naming
Ask the patient to name high-frequency objects (e.g., watch) and low-frequency parts (e.g., watch strap/buckle).
- Anomia is the most sensitive sign of aphasia but is non-specific.
Step 5: Reading and Writing
Ask the patient to read a sentence aloud and write a sentence.
- This helps distinguish aphasia from isolated motor speech disorders.
Canadian Context: Cultural and Linguistic Considerations
Canada is a bilingual country with a diverse population.
- Bilingualism: Aphasia may affect languages differently. Always test in the patient’s primary language if possible.
- Indigenous Health: Be mindful of Indigenous languages. Use professional interpreters (Collaborator role) rather than family members when possible to ensure accurate neurological assessment.
Investigations
-
Neuroimaging (Acute):
- CT Head (Non-contrast): First-line to rule out hemorrhage (Stroke Protocol).
- CTA (Computed Tomography Angiography): To identify large vessel occlusion (LVO) for potential endovascular thrombectomy (EVT).
- MRI Brain: More sensitive for small ischemic strokes or tumors.
-
Bedside Screening:
- MoCA (Montreal Cognitive Assessment): Developed in Canada; sensitive for mild cognitive impairment and language deficits.
Management
1. Acute Phase (Stroke Protocol)
If the aphasia is sudden (acute stroke), time is brain.
- Thrombolysis (tPA): If within 4.5 hours of symptom onset and no contraindications.
- Endovascular Thrombectomy (EVT): For Large Vessel Occlusion (LVO) in the anterior circulation, typically up to 6 hours (and up to 24 hours in select patients based on imaging perfusion).
2. Rehabilitation
- Speech-Language Pathology (SLP): Early referral is essential.
- Communication Strategies: Use picture boards, slow speech, and simple sentences.
3. Etiology-Specific Management
- Tumor: Neurosurgery/Oncology referral.
- Dementia (Primary Progressive Aphasia): Supportive care, SLP.
Key Points to Remember for MCCQE1
- Sudden onset aphasia is a stroke until proven otherwise.
- Wernicke’s aphasia can be mistaken for acute psychosis or delirium because the patient sounds “confused” and fluent.
- Conduction aphasia presents as a patient who understands perfectly and speaks fluently but cannot repeat anything.
- Dysarthria without aphasia suggests subcortical, brainstem, or cerebellar pathology, whereas Aphasia implies cortical (dominant hemisphere) pathology.
- Canadian Stroke Best Practice Recommendations emphasize admission to a dedicated stroke unit for better outcomes.
Sample Question
Stem: A 72-year-old female presents to the Emergency Department with sudden onset of speech difficulty that started 2 hours ago. She has a history of atrial fibrillation and hypertension. On examination, she appears frustrated. She is unable to speak in full sentences, producing only short, halting phrases such as “Hospital… help… arm.” She follows commands appropriately, such as “Close your eyes” and “Squeeze my hand.” When asked to repeat “The sky is blue,” she struggles and says “Sky… blue.” Neurological exam reveals weakness in the right face and right arm.
Question: Which of the following is the most likely diagnosis?
- A. Wernicke’s aphasia
- B. Conduction aphasia
- C. Broca’s aphasia
- D. Transcortical motor aphasia
- E. Global aphasia
Explanation
The correct answer is:
- C. Broca’s aphasia
Detailed Explanation: The patient presents with non-fluent aphasia (short, halting phrases), intact comprehension (follows commands), and impaired repetition. This triad is classic for Broca’s aphasia. The associated right face and arm weakness supports a lesion in the left posterior inferior frontal gyrus (Broca’s area) and the adjacent primary motor cortex, typically due to an occlusion of the superior division of the left Middle Cerebral Artery (MCA).
- Option A (Wernicke’s): Incorrect. Wernicke’s presents with fluent, nonsensical speech and impaired comprehension.
- Option B (Conduction): Incorrect. Conduction aphasia presents with fluent speech and intact comprehension, but impaired repetition.
- Option D (Transcortical Motor): Incorrect. This presents similarly to Broca’s (non-fluent, intact comprehension) but with preserved repetition.
- Option E (Global): Incorrect. Global aphasia involves severe deficits in fluency, comprehension, and repetition.
Canadian Guidelines
Canadian Stroke Best Practice Recommendations (Heart & Stroke Foundation)
- Screening: All stroke patients should be screened for communication deficits (aphasia, dysarthria) prior to discharge.
- Rehabilitation Intensity: Patients with aphasia should receive individualized speech-language therapy as early as possible once medically stable.
- Family Involvement: Education and training for communication partners (family/caregivers) is a recommended standard of care in Canada.
References
- Heart & Stroke Foundation of Canada. Canadian Stroke Best Practice Recommendations: Rehabilitation, Recovery, and Community Reintegration. Available at: strokebestpractices.ca
- Kasper, D. L., et al. Harrison’s Principles of Internal Medicine. 21st Edition. McGraw Hill.
- Medical Council of Canada. MCCQE Part I Objectives: Neurology.
- Toronto Notes. Neurology Chapter: Aphasia. 2023 Edition.