Neurologic system

Neurologic System Overview

  • Chapter 24 by Brittany LaCasse, MSN, RN

Screening Neurological Exam

  • Purpose: To assess clients who are well or report no significant subjective history.

  • Sequence of Assessment:

    • Mental Status

    • Cranial Nerves

    • Motor System

    • Sensory System

    • Reflexes

Complete Neuro Exam and Recheck

  • Indication: Perform on clients with neurological deficits.

  • Key Components of Assessment:

    • Level of consciousness (change in LOC is the most important indicator)

    • Orientation

    • Motor function

    • Pupillary response

    • Vital signs, noting late signs of increased intracranial pressure (ICP)

Pronator Drift

  • Assessment: Client holds both arms forward for 10-20 seconds.

  • Normal Response: Arms remain steady, no drift.

  • Abnormal Response: Downward unilateral drift and turning in of the forearm indicates hemiparesis.

Glasgow Coma Scale (GCS)

  • Purpose: To assess the level of consciousness using a response scale:

    • Eye Opening Response:

      • Spontaneous: 4 points

      • Response to verbal command: 3 points

      • Response to pain (not facial): 2 points

      • No response: 1 point

    • Verbal Response:

      • Oriented: 5 points

      • Confused but answers questions: 4 points

      • Inappropriate verbal responses: 3 points

      • Incomprehensible sounds: 2 points

      • No verbal response: 1 point

    • Motor Response:

      • Obeys commands: 6 points

      • Purposeful movement to pain: 5 points

      • Withdraws from pain: 4 points

      • Abnormal flexion (decorticate) or extensor response (decerebrate): 2-3 points

      • No motor response: 1 point

  • Scoring Explanation:

    • Minor Brain Injury: 13-15 points

    • Moderate Brain Injury: 9-12 points

    • Severe Brain Injury: 3-8 points

Posturing Responses

  • Decorticate Posture: Arms flexed towards chest ('C' shape); indicates problems with the cervical spinal tract.

  • Decerebrate Posture: Arms extended and rigid; indicates problems in the midbrain or pons.

Nurse Check Example

  • Scenario: Assessment of client admitted after a fall.

  • Client's GCS score based on assessment: opens eyes to speech, obeys commands, responds nonsensically to questions.

Cranial Nerves Overview

  • **Cranial Nerve Functions:

    • CN I (Olfactory):** Smell

    • CN II (Optic):** Visual acuity

    • CN III (Oculomotor):** Pupil dilation

    • CN IV (Trochlear):** Vertical eye movement

    • CN V (Trigeminal):** Facial sensation and jaw muscles

    • CN VI (Abducens):** Lateral eye movement

    • CN VII (Facial):** Facial expressions

    • CN VIII (Acoustic):** Hearing and balance

    • CN IX (Glossopharyngeal)/CN X (Vagus):** Gag reflex, uvula rise midline

    • CN XI (Spinal Accessory):** Shoulder shrug, head rotation against resistance

    • CN XII (Hypoglossal):** Tongue movement, symmetrical protrusion

Cranial Nerves Testing Details

  • CN I (Olfactory): Nerve fibers transmit odor information from nasal cavity to brain.

  • CN II (Optic): Assess visual acuity with Snellen chart, visual fields, color perception.

  • CN III, IV, VI (Oculomotor, Trochlear, Abducens): Check pupillary reaction, cardinal positions of gaze, assess for nystagmus.

  • CN V (Trigeminal): Light touch sensation on forehead, cheek, jaw; palpate jaw while clenching teeth for motor function.

  • CN VII (Facial): Evaluate motor function through facial expressions (smile, frown, etc.).

  • CN VIII (Acoustic): Perform whispered voice test, Weber and Rinne tests for hearing acuity.

  • CN IX/X (Glossopharyngeal/Vagus): Check uvula movement and gag reflex reaction.

  • CN XI (Spinal Accessory): Check size of sternomastoid and trapezius muscles during resistance tests.

  • CN XII (Hypoglossal): Inspect midline position during tongue protrusion; assess clear speech.

Cerebellar Function

  • Tests for Functionality:

    • Rapid Alternating Movements (RAM)

    • Finger to Nose Test (point-to-point)

    • Heel to Shin Test

  • Balance Testing:

    • Observe normal gait, tandem walking, Romberg Test (stand with feet together, arms at the side, eyes closed, and assess for sways/falls)

Sensory Tests

  • Evaluate Sensation of:

    • Touch & Pain

    • Vibration

    • Position (Kinesthesia):awareness of the position and movement of the parts of the body by means of sensory organs (proprioceptors) in the muscles and joints.

    • Stereognosis: the mental perception of depth or three-dimensionality by the senses, usually in reference to the ability to perceive the form of solid objects by touch.

    • Graphesthesia:the ability to recognize writing or symbols on the skin by touch

    • Filament Testing:a medical procedure that uses a small strand of nylon to assess nerve damage, or peripheral neuropathy

      - Reflexes

  • Purpose: Basic defense mechanisms of the nervous system; quicker reactions to potentially harmful stimuli.

  • Deep Tendon Reflex Grading System:

    • 0: absent

    • 1+: hyporeflexic

    • 2+: normal

    • 3+: brisk, without clonus

    • 4+: brisk, with clonus

Deep Tendon Reflex Locations

  • A: Biceps

  • B: Brachioradialis

  • C: Triceps

  • D: Quadriceps/Patellar

  • E: Achilles

  • F: Clonus

Developmental Competence

  • Neurologic system not fully developed at birth; myelinization enhances response to stimuli.

  • In older adults:

    • Loss of neuron structure occurs, leading to reduced muscle, strength, coordination, reflexes.

    • Sensory changes include diminished sensation in touch, pain, taste, and smell.

Reflex Examples

  • Palmar Grasp Reflex- a primitive reflex observed in infants where they automatically grasp an object placed in their palm, indicating normal neurological function.

  • Babinski Reflex- a neurological reflex typically seen in infants where the toes fan out when the sole of the foot is stroked, indicating the integrity of the corticospinal tract.

  • Plantar Reflex: Toes fanning out upon flexing inward due to external stimulation (different response in adults).

Health Promotion & Client Teaching

  • Key Topic: Understanding stroke (brain attacks) which occur due to interrupted blood flow to parts of the brain.

  • Risk Factors:

    • Hypertension

    • Smoking

    • Heart disorders (e.g., atrial fibrillation, hyperlipidemia)

Tremors vs. Seizures

  • Tremors:

    • Involuntary back-and-forth movements

    • Rest tremors occur at rest; intention tremors during voluntary movement.

  • Seizures: Excessive neuronal discharge; phases include

  • prodromal:an early sign or symptom that indicates the beginning of a disease or condition

  • ictal:the middle stage of a seizure, from the first symptom to the end of the seizure activity

  • postictal:A recovery phase characterized by confusion, fatigue, and potential temporary neurological deficits.