Neuroscience: Brain Circulation and Matter

Posterior Cerebral Artery

• Contralateral sensory loss without motor loss

Posterior Circulation

• Composed of two vertebral arteries
• Supplies brainstem, cerebellum, medulla, and upper spinal cord
• Vertebral arteries combine to form basilar artery
• Supplies pons and cerebellum
• Basilar divides into right and left posterior cerebral arteries
• Supplies occipital and temporal lobes
• Anterior and posterior communicating arteries interconnect and form the Circle of Willis

White Matter

• Appears white due to fat within myelin
• Composed of axons
• Carries information away from cell bodies
• Found in the brain and spinal cord
• Bundled together to form tracts

Gray Matter

• Areas with large numbers of cell bodies and dendrites
• Cell bodies produce gray color
• Covers the entire cerebrum (the cerebral cortex)
• Also deep in the spinal cord
• Dorsal (posterior) transmits sensory stimuli
• Ventral (anterior) transmits motor impulses

Brain Areas and Functions

• Frontal lobe - primary motor cortex, Broca's area (speech production)
• Parietal lobe - primary sensory cortex, short-term memory functions
• Temporal lobe - primary auditory cortex, Wernicke's area (speech comprehension)
• Occipital lobe - primary visual cortex, organizes, integrates, and interprets visual information

Brain Structures and Functions

• Cerebellum: regulation of posture, muscle tone, and volitional/automatic movement
• Parietal Lobe: primary sensory cortex, short-term memory
• Brain Stem: houses reflex centers for autonomic body functions, responsible for homeostatic function
• Occipital Lobe: organizes, integrates, and interprets visual information
• Cerebellum: controls balance and complex muscular movements, assists with posture maintenance
• Temporal Lobe: primary auditory cortex
• Frontal Lobe: primary motor cortex

Sensory Pathways

• Lateral Spinothalamic Tract: pain and temperature sensation
• Anterior Spinothalamic Tract: crude touch sensation

Equilibrium Tests

• Check balance and ability to stand still
• Performed while standing upright
• Focus on gross motor skills (big movements)
• Looks at both static (still) and dynamic (moving) positions

Nonequilibrium Tests

• Assess movement and balance while sitting
• Performed while seated
• Involves both gross and fine motor skills
• Examines static and mobile aspects of movement

PNF Techniques and Their Primary Stages

• Slow Reversal: Controlled Mobility, promotes smooth transitions between muscle groups, enhances coordination of movements.
• Hold Relax Active Movement: Mobility, increases range of motion by reducing muscle tension, helps overcome restrictions in movement.
• Rhythmic Rotation: Controlled Mobility, improves coordination and timing of movements, enhances proprioception during dynamic activities.
• Rhythmic Stabilization: Stability, strengthens stabilizing muscles, improves ability to maintain position against external forces.
• Alternating Isometrics (AI): Stability, develops strength and control for maintaining posture, enhances ability to resist external forces.
• Agonist Reversal: Controlled Mobility, promotes smooth transitions between muscle groups, improves coordination of movements.
• Resisted Progression: Skill, develops strength and control for complex movements, enhances precision and speed of actions.

Incomplete Spinal Cord Syndromes

• Anterior Cord Syndrome: incomplete, from cervical flexion, loss of motor function, no pain/temperature sense below level of lesion.
• Central Cord Syndrome: incomplete, from cervical hyperextension, damages spinothalamic/corticospinal tract/dorsal columns. Upper extremity deficits are more present, more motor deficits than sensory.
• Posterior Cord Syndrome: incomplete, from a variety of causes, motor function preserved, loss of pain perception, proprioception, 2 point discrimination, stereogenesis.

Spinal Cord Injuries

• Cervical levels:
  • C1-C3: head turning
  • C4: breathing, shoulder shrug
  • C5: arm elevation, elbow flexion
  • C6: wrist extension, tenodesis grasp
  • C7: elbow extension, hand function
  • C8: finger dexterity
• Incomplete injuries have better outcomes than complete injuries.
• T1-T11: therapeutic ambulation with orthoses in parallel bars
• T12-L2: household ambulation with orthoses
• L3: community ambulation with orthoses
• L4-L5: community ambulation, may only need AFO and AD
• S1-S2: AFO
• C6: able to use tenodesis
• C4: will require full-time care
• C7: can independently complete a squat pivot or sliding board transfer
• C8: improved hand function allows for wheelies in a wheelchair
• C5: with adaptations, this is the highest level that may use a manual wheelchair
• Selective stretching of the long finger flexors can enhance grasp with tenodesis in a C6 ASIA A injury.
• ASIA Classification Scale: The labeled motor level of a spinal cord injury is the lowest level with 3/5 strength or the superior segment with 5/5 strength.

Cardiac Rehab Phase II

• EKG is required during all sessions
• EKG is required during the exercise test prior to starting rehab
• Goal is to increase exercise capacity to 7 METS

Cerebral Palsy - GMFCS Levels

• Level 1: walks without limitations, can run and jump with decreased speed and coordination.
• Level 2: walks with limitations, needs assistance with uneven surfaces, can minimally run or jump.
• Level 3: walks using a hand-held mobility device, may be able to climb stairs with a railing, may propel a manual wheelchair.
• Level 4: self-mobility with limitations, may use a powered wheelchair.
• Level 5: transported in a manual wheelchair.

Cardiovascular Testing

• VO2 max testing targets endpoint heart rate.
• Submaximal testing is used for symptomatic individuals.

ACSM Absolute Contraindications

• Severe arterial hypertension (systolic blood pressure > 200mmHg and/or diastolic blood pressure > 110mmHg) at rest.
• Heart rate is used for VO2 calculations.

Termination Criteria for GXT

• Blood pressure:
  • SBP fails to rise with increase in workload.
  • SBP drops more than 10mmHg.
  • SBP increases to more than 250mmHg.
  • DBP rises more than 20mmHg from resting value.
  • DBP rises above 110-120mmHg.
• Heart rate:
  • Decrease in HR with increase in workload.
  • Increase in HR > 220 beats per minute.
  • Inappropriate bradycardia.
• Signs and symptoms:
  • Subject requests to stop.
  • Progressive angina (stop at 3+)
  • Progressive dyspnea (stop at 3+)
  • Marked dyspnea.
  • Cyanosis.
  • Vasoconstriction (pale, cold, clammy skin).
  • Cessation of sweating.
  • Syncope.
• Malfunctioning equipment.

Exercise Tests

• Astrand cycling test: steady-state test.
• Bruce Treadmill test: incremental test.
• Seated step test.

Beta Blockers

• "lol" - medications that treat hypertension, heart failure, myocardial infarction, and angina.

Primitive Reflexes

• Integrated by 2-6 months old - spinal cord level
• Rooting: 28 weeks gestation → 3 months - sucking finger, interferes with midline control of head, visual tracking, and interactions.
• Sucking: survival reflex, 28 weeks gestation -> 2-5 months.
• Moro: 28 weeks gestation → 5-6 months - abduction and extension of upper extremities -> supine -> head extends back 20-30 degrees.
• Crossed Extension: 28 weeks gestation → 1-2 months - flexion and adduction of the other leg, extension to push examiner away.
• Plantar grasp: supine - flexes toes - if not integrated, no ability to stand with flat feet, bad balance, no weight shifting in standing.
• Galant: 32 weeks gestation → 2 months - prone brushing on side of trunk -> trunk curves to stimulus (same side) - if not integrated, bad sitting balance can lead to scoliosis.
• Palmer grasp: last simple reflex to integrate - supine; index finger in hand, - if not integrated, weight bearing on open hand for propping is bad, bad creeping, bad protective response.
• Spontaneous Stepping: if bad?