Acquired Language Disorders

Introduction to Acquired Language Disorders

• Acquired language disorders are not developmental in nature; they are not conditions a person is born with or develops during childhood.

• These disorders result from an acquired neurological impact or insult to the brain.

• Clinical interactions for these disorders typically occur in medical settings, such as hospitals, acute care, or skilled nursing facilities ($SNF$).

Anatomy of the Nervous System

• The nervous system is the organization of nerves in the body that controls bodily functions.

• Central Nervous System (CNS):

  • Consists of the brain and the spinal cord.

• Peripheral Nervous System (PNS):

  • Made up of all nerves located outside the brain and spinal cord.

  • Somatic System: Controls muscles under volitional (voluntary) control, such as wiggling a finger.

  • Autonomic System: Controls functions not under volitional control, such as heartbeat and digestion. Breathing is largely autonomic, though it has limited volitional control (holding one’s breath).

Cerebral Anatomy and Functional Specialization

• The brain is composed of the cerebrum, the brain stem, and the cerebellum.

• The Cerebrum: Divided into $4$ lobes.

• Protective Layers:

  • Skull: The bony housing of the brain and facial bones.

  • Ventricles: Spaces filled with cerebrospinal fluid ($CSF$) that cushion the brain, keep it moist/nourished, and regulate intracranial pressure.

  • Meninges: The lining of the brain consisting of $3$ parts:

    • Dura mater: The outer layer.

    • Arachnoid: The middle layer, characterized as spongy and web-like (named like a spider web).

    • Subarachnoid space: Located under the arachnoid, filled with $CSF$ for cushioning.

    • Pia mater: The innermost layer.

• Frontal Lobe:

  • The largest lobe.

  • Contains the motor cortex, which controls voluntary motor movement.

  • Broca’s Area: Located in the left frontal lobe (back portion). It is responsible for speech production and expressive language.

  • Executive Function: Responsible for planning, initiation, cognitive features, and personality. Damage to the frontal lobe can result in significant personality changes.

• Parietal Lobe:

  • Located just behind the frontal lobe.

  • Main functions involve sensation, including touch, temperature, pain, and pressure.

  • Angular Gyrus: Responsible for integrating sensory information (vision, hearing, touch) to make sense of stimuli. Damage here leads to poor language comprehension because the patient cannot integrate visual (mouth movements) and auditory (speech) information.

• Temporal Lobe:

  • Sits above the ear.

  • Contains the primary auditory cortex, where sound is interpreted.

  • Wernicke’s Area: Located in the left temporal lobe. It is the center for language comprehension.

  • Arcuate Fasciculus: A band of tissues connecting Broca’s and Wernicke’s areas to allow for communication between comprehension and expression centers.

• Occipital Lobe:

  • Located at the very back of the brain.

  • Responsible for visual processing; it has the least direct involvement with speech-language pathology tasks.

The Brainstem and Cerebellum

• Brainstem Components:

  • Midbrain: Communicates data between the outside of the brain and the inside of the cerebrum.

  • Pons: Acts as a communication bridge between the cerebellum and the rest of the nervous system.

  • Medulla (Medulla Oblongata): Controls nonvolitional autonomic functions, including heart rate, breathing, digestion, sneezing, and swallowing.

• Cerebellum:

  • Connected to the cerebrum and the brainstem via the pons and medulla.

  • Responsible for motor coordination, sending feedback to the motor cortex to maintain posture and balance.

  • May also possess non-motor functions, including language processing and cognitive functions.

Spinal Cord and Peripheral Nervous System

• Spinal Cord: Housed within the spinal column for protection. It extends from the brainstem.

• Spinal Nerves: $31$ pairs of nerves, containing both sensory and motor components.

  • Efferent Track: The motor track. Takes data from the brain to the spinal nerves to initiate movement (moves away from the brain).

  • Afferent Track: The sensory track. Takes information from the body's extremities back to the brain (moves toward the brain).

Cranial Nerves and Clinical Significance

• There are $12$ pairs of cranial nerves connected directly to the brain.

• Key Nerves for SLPs:

  • V - Trigeminal: Involved in facial sensation and mastication (chewing). It has both sensory and motor functions.

  • VII - Facial: Sensory and motor. Controls facial expression muscles and sensation of taste.

  • VIII - Vestibulocochlear (Auditory Nerve): Sensory. Provides information on hearing and balance.

  • IX - Glossopharyngeal: Sensory and motor. Involved in taste and the gag reflex (critical for preventing aspiration during swallowing).

  • X - Vagus: Known as the "wandering nerve" due to its length. Sensory and motor. Controls the gag reflex and innervates parts of the larynx. It can be damaged during heart surgeries, impacting voice.

  • XII - Hypoglossal: Motor nerve. Controls tongue movements, essential for swallowing and speech.

Etiology of Brain Damage

• Traumatic Brain Injury (TBI): Result of accidents, such as car crashes.

• Cerebrovascular Accident (CVA): Commonly known as a stroke; occurs when blood supply to the brain is interrupted.

  • Hemorrhagic Stroke: A blood vessel bursts.

  • Ischemic Stroke: A blood vessel is blocked by a clot.

  • Transient Ischemic Attack (TIA): Sometimes called a "mini-stroke." A temporary blockage where the clot passes on its own.

• Other Causes: Seizures and neurodegenerative conditions (e.g., Multiple Sclerosis, Huntington's disease).

• Factors of Impact: The extent of damage and the specific location determine the functional consequences (speech, language, cognition, motor control, personality, or swallowing).

Aphasia: Definition and Symptomatology

• Aphasia: A language disorder caused by brain damage, characterized by difficulty understanding or expressing language (not a disorder of speech sound production).

• Expressive Symptoms:

  • Anomia: Difficulty thinking of words or names for people/things.

  • Paraphasia: Word substitutions.

    • Phonemic Paraphasia: Substituting words based on sound similarity (e.g., saying "cat" instead of "car").

    • Verbal Paraphasia: Substituting associated words (e.g., saying "truck" instead of "car").

    • Neologism (Neologistic Paraphasia): Creating made-up words (e.g., saying "flugel" instead of "car").

  • Agrammatism: Often called "telegraphic speech." Content words are present, but grammatical morphemes are missing, resulting in halting, disfluent speech (e.g., "I go car" instead of "I am going to get in the car").

  • Jargon: Fluent speech that is meaningless.

  • Verbal Stereotypies: Rote, stereotypical responses. Example: Groot from Guardians of the Galaxy says "I am Groot" to mean everything.

• Receptive Symptoms:

  • Verbal Agnosia: Hearing the sound of words but not recognizing their meaning.

  • Visual Agnosia: Being able to see something but not identifying it by sight; identification may return through touch.

• Written Language Symptoms:

  • Agraphia: Difficulty writing words.

  • Alexia: Acquired loss of the ability to read. (Distinguished from dyslexia, which is developmental).

Classification of Aphasia Syndromes

• Classification is based on three binary questions:

  1. Is the patient fluent (smooth, easy) or nonfluent (halting, agrammatical)?

  2. Is comprehension spared (intact) or impaired?

  3. Is repetition spared or impaired?

• Anomic Aphasia: The mildest form. Fluent, intact comprehension, intact repetition. Primary deficit is word finding.

• Wernicke’s Aphasia: Fluent, impaired comprehension, impaired repetition. Speech lacks meaning; patients often lack awareness of their errors and may become combative if corrected.

• Broca’s Aphasia: Nonfluent ("broken"), intact comprehension, impaired repetition. Patients are aware of their errors.

• Global Aphasia: The most severe form. Nonfluent, impaired comprehension, impaired repetition.

• Conduction Aphasia: Fluent, intact comprehension, but impaired repetition.

• Transcortical Aphasias: Include Mixed Transcortical, Transcortical Motor, and Transcortical Sensory. The defining feature is that repetition is typically spared.

Assessment Process in Medical Settings

• Initial Step: Requires a physician’s order in acute care or hospitals.

• Review: Medical diagnosis, doctor/nurse notes, imaging (radiology reports).

• Clinical Components: Interview (client/family), Oral Mechanism Exam.

• Formal Assessments: The Boston and The Western are popular, but they take $2$ to $3$ hours and are rarely used at bedside in acute care.

• Informal Tasks: Dynamic and quick observation of:

  • Labeling pictures/objects (e.g., clock, water bottle).

  • Binary responses (Yes/No questions: "Are we in the hospital?").

  • Repeating words and sentences.

  • Rote productions (e.g., counting from $1$ to $10$).

  • Open-ended questions and reading/writing tasks.

• Prior Level of Function (PLOF): Establishing the patient's status before the event (e.g., stroke) to set reasonable, functional therapy expectations. If a patient had pre-existing dementia, therapy goals must reflect that baseline.

Principles of Aphasia Treatment and Neuroplasticity

• Spontaneous Recovery: A period during the first few weeks after a stroke when the brain makes improvements on its own. It is the optimal time to begin therapy.

• Neuroplasticity: The brain’s ability to be flexible and retrain undamaged portions to perform the functions of damaged cells (re-routing), as dead neurons cannot be regenerated.

• Goal: Functional communication to prevent isolation and facilitate social participation.

• Approaches:

  • Direct Training: Behavioral therapy, drills, and practice to fix deficits.

  • Compensatory Strategies: Teaching alternatives (e.g., pointing if a patient cannot speak).

• Family Counseling: involves managing prognosis expectations and providing emotional support.

Cognitive Communication Disorders

• Impairments: Affect attention, awareness, orientation, memory, executive function (planning/sequencing), reasoning, and pragmatics.

• Etiology: Stroke, $TBI$, dementia, normal aging, brain infections, or right hemisphere damage.

• Therapy Goal: Return to prior level of independence and mastery of Activities of Daily Living (ADLs) (brushing teeth, meds, cooking, managing finances).

• Safety issues: Sequence memory for medications and physical safety limitations (e.g., remembering to use a wheelchair).

• Assessment Tools: Mini-Mental State Examination ($MMSE$) and the St. Louis Mental Status Exam ($SLUMS$).

Dementia: Characteristics and Management

• Definition: Intellectual deterioration; it is a symptom of underlying diseases (Alzheimer's, Huntington's, Parkinson's), not a disease itself.

• Common Symptoms: Impaired memory for new information, poor reasoning, depression, mood swings, anomia, paraphasia, and eventually echolalia or mutism.

• SLP Role:

  • Caregiver Education: Teaching caregivers to speak simply, be patient, and use "kind redirection" (e.g., saying "she's not here right now" instead of "she's dead") to avoid re-traumatizing the patient.

  • Compensatory Strategies: Creating memory books, using visual cues (post-it notes), and teaching self-advocacy.

  • Ethical Discharge: Recognizing when treatment is no longer effective and discharging the patient once the ability to communicate wants/needs can no longer be improved.

Right Hemisphere Disorder (RHD)

• Functional Differences: The right hemisphere typically controls nonlinguistic elements (gestures, prosody, tone), math skills, music melody, and sustained attention.

• Deficits:

  • Prosopagnosia: Inability to recognize familiar faces.

  • Pragmatics: Difficulty understanding non-literal language (sarcasm, humor, metaphors) and recognizing emotions through facial expressions.

  • Inferencing: Difficulty putting small details together to see the "big picture."

  • Visual-Spatial Deficits: Tunnel vision (simultaneously) or acquired color blindness.

  • Neglect: Forgetting/unaware of one half of the body or environment (usually the left side). Tested via the "Draw a Clock Test."

  • Neuropsychiatric Delusions (not treated by SLPs):

    • Capgras Delusion: Believing a loved one has been replaced by an impostor.

    • Fregoli Delusion: Believing different people are actually one person disguised as others.

• Assessment: Informal tests for facial expression recognition, inferencing (e.g., the coat/winter scenario), and discourse observation.