Understanding Stroke, Brain Injury, and Hearing Impairments

Stroke: Types and Characteristics

Types of Stroke

• Ischemic: Blockage of a cerebral vessel to the brain (most common). Includes thromboembolic (blood clot in arteries) and embolic (blood clot originating away from the brain).
• Hemorrhagic: Rupture in the brain. Includes intracerebral (bursts in the brain and spills) and subarachnoid (starts in an artery, spills on the surface of the brain).
• Transient Ischemic Attack (TIA): A "mini-stroke" characterized by a brief episode.

Risk Factors

Age, heredity, prior stroke or heart attack, gender, high blood pressure, diabetes, elevated cholesterol, arrhythmias, tobacco use, obesity, poor diet, and physical inactivity.

Stroke Rehabilitation Principles

Rehabilitation emphasizes a multidisciplinary approach including medications, physical therapy (PT), occupational therapy (OT), speech therapy, orthotics, counseling, and case management. Recovery determination has evolved; the window of recovery is unlimited, and impairment/disability is not fixed. The treatment approach is restorative.

Functional Limitations and Work Factors

Limitations include stamina, strength, mobility, mood/behavior, attention, decision-making, impulse control, complex skills, motor control, speed, social skills, and communication. Work capacity depends on the degree of weakness, presence of apraxia, occupation type, and independence in Activities of Daily Living (ADLs).

Brain Injury: TBI and Non-TBI

Incidence and Prevalence

There are 1.4 million head injuries in the US yearly, with a 95% survival rate.

Types of Brain Injury

• TBI (Traumatic Brain Injury): Open/penetrating (gunshot, stabbing), closed/concussion, and falls.
• Non-TBI: CVA (reduced blood supply), anoxia (lack of oxygen), hypoxia (decreased oxygen to organs), electrocution (disruption of neurons), cardiac arrest, and encephalopathy (HTN, infections, toxins, multiple blows to the head).

Risk Factors and Mechanisms

• Primary: Coup (moving object strikes head) and contrecoup (head strikes stationary object).
• Secondary: Hemorrhage or infarction, edema in white matter, diffuse brain swelling, ischemic brain damage, brain shift/herniation, and raised intracranial pressure.

Causes and Consequences

Causes include motor vehicle accidents (60%), falls (11%—most likely under 5 and over 75), assault (19%), sports/rec (3%), and miscellaneous (17%). Consequences include learning/memory difficulties, problem-solving issues, slow thinking, depression, and balance problems. Functional work limitations often involve frontal lobe (executive function) and cerebellum (balance) damage.

Hearing Impairments

Basic Anatomy

Includes the tympanic membrane (ear drum), outer/middle/inner ear, auditory nervous system, and the eustachian tube (connection between throat and ear).

Types of Hearing Loss

• Conductive: Reduced hearing ability despite a functioning cochlea.
• Sensorineural: Reduced ability to hear due to damage to the auditory nervous system or cochlea (sensory and neural categories).
• Mixed: Both conductive and sensorineural loss present in the same ear.

Severity Levels

• Mild: 25 dB to 40 dB
• Moderate: 40 dB to 65 dB
• Severe: 65 dB to 90 dB