Neurological Examination Guide: Nervous System Assessment

Neurological Examination Foundation

Systematic neurological examination enables localization of nervous system pathology. Understanding normal neurological function guides identification of deficits. Proper technique ensures reproducible, reliable findings.

Neurological Assessment Facts:

• Neurological examination detects 85% of clinically significant lesions
• Thorough neurological exam takes 20-30 minutes
• Focused exam on specific complaint requires 5-10 minutes
• Operator skill significantly affects test sensitivity and specificity
• Baseline examination essential for monitoring change

Mental Status Examination

Level of Consciousness

• Alert: Awake and aware of surroundings
• Lethargic: Drowsy but arousable with normal stimulation
• Obtunded: Requires vigorous stimulation to arouse
• Stuporous: Only arouses with painful stimulation
• Comatose: No response to any stimulation

Orientation Assessment

• Person: What is your name?
• Place: Where are we now?
• Time: What day/month/year?
• Disorientation in any domain indicates confusion

Cognition and Speech

• Attention: Can patient focus and sustain attention?
• Memory: Recent (past few days) and remote (childhood)
• Language: Speech fluent, comprehension intact?
• Calculation: Serial 7s, arithmetic problems
• Abstract thinking: Proverb interpretation

Affect and Mood

• Mood: Patient's subjective emotional state
• Affect: Observed emotional expression (appropriate or not)
• Thought process: Organized, logical, or tangential

Cranial Nerve Examination (CN I-XII)

CN I - Olfactory Nerve

• Test: Smell familiar odor (coffee, lemon)
• Occlude one nostril, present odor to other
• Deficiency may indicate anterior fossa lesion or dementia

CN II - Optic Nerve

• Visual acuity: Read chart at distance
• Visual fields: Confrontation testing (identify fingers)
• Pupils: Reactive to light, sluggish, or fixed?
• Afferent pupil defect: Marcus Gunn pupil suggests optic nerve lesion

CN III, IV, VI - Oculomotor, Trochlear, Abducens

• Eye movements: Follow "H" pattern to test all directions
• Normal: Smooth, conjugate (together) eye movements
• Nystagmus: Rhythmic, involuntary eye movements
• Dysconjugate: Eyes don't move together (nerve palsy)
• Diplopia: Double vision suggests nerve or muscle dysfunction

CN V - Trigeminal Nerve

• Motor: Clench teeth, palpate masseter muscles
• Sensory: Light touch and pain to three divisions (forehead, cheek, jaw)
• Reflex: Corneal reflex (blink when cornea touched)

CN VII - Facial Nerve

• Motor: Raise eyebrows, close eyes, smile, pucker lips
• Bell's palsy: Unilateral facial weakness
• Taste: Salt on anterior 2/3 of tongue

CN VIII - Vestibulocochlear Nerve

• Hearing: Whisper test, Weber and Rinne tests
• Balance: Romberg test (stand with eyes closed)

CN IX, X - Glossopharyngeal, Vagus

• Gag reflex: Touch posterior pharynx (normal = gag)
• Voice: Hoarse or nasal quality?
• Palate: Uvula midline when saying "aaah"?
• Deviation suggests nerve palsy

CN XI - Accessory Nerve

• Shoulder shrug: Trapezius strength
• Head turn: Sternocleidomastoid strength
• Weakness suggests spinal accessory nerve lesion

CN XII - Hypoglossal Nerve

• Tongue: Stick out (midline or deviation?)
• Weakness: Deviation toward weak side
• Atrophy or fasciculations suggest motor neuron disease

Motor Examination

Strength Testing (0-5 Grading)

• 0 = No muscle contraction
• 1 = Flicker of muscle, no movement
• 2 = Movement possible with gravity eliminated
• 3 = Movement against gravity only
• 4 = Movement against gravity and mild resistance
• 5 = Normal strength

Muscle Tone Assessment

• Normal: Smooth resistance throughout movement
• Hypertonia: Increased resistance (spasticity or rigidity)
• Hypotonia: Decreased resistance (flaccidity)
• Rigidity: Uniform resistance throughout movement (Parkinson's)

Pattern Recognition

• Upper motor neuron: Weakness in legs, increased tone, hyperreflexia
• Lower motor neuron: Weakness, atrophy, decreased tone, hyporeflexia

Sensory Examination

Modalities to Test

• Light touch: Cotton wisp
• Pain: Pin or safety pin
• Proprioception: Joint position sense
• Vibration: Tuning fork at bony prominences
• Temperature: Warm and cold objects

Sensory Pattern Recognition

• Peripheral neuropathy: Stocking-glove pattern (distal>proximal)
• Spinal cord lesion: Level of sensory loss (spinal level)
• Brain lesion: Contralateral hemi-sensory loss

Reflex Testing

Deep Tendon Reflexes (0-4+ Grading)

• 0 = Absent (normal in some)
• 1+ = Hyporeflexic (decreased)
• 2+ = Normal
• 3+ = Hyperreflexic (increased)
• 4+ = Clonus (repetitive contractions)

Common Reflexes

• Biceps: Tap biceps tendon (C5-C6)
• Triceps: Tap triceps tendon (C7-C8)
• Patellar: Tap patellar tendon (L3-L4)
• Achilles: Tap Achilles tendon (S1-S2)

Cerebellar Function

Coordination Tests

• Finger-to-nose: Rapid finger to nose and back
• Rapid alternating movements: Tap hand repeatedly
• Heel-to-shin: Run heel down anterior shin
• Dysmetria: Overshooting or undershooting target

Gait Assessment

• Observe: Base, stride length, arm swing, posture
• Normal: Erect, smooth, coordinated
• Ataxia: Unsteady, wide-based gait
• Spasticity: Scissor gait or stiffness
• Weakness: Foot drag or circumduction

Key Takeaways: Neurological Mastery

• Perform systematic neurological examination every patient
• Assess mental status comprehensively (consciousness, orientation, cognition)
• Test all 12 cranial nerves appropriately
• Grade strength accurately (0-5 scale)
• Assess sensory modalities and recognize patterns
• Test deep tendon reflexes bilaterally
• Evaluate cerebellar function
• Observe gait and recognize abnormal patterns
• Localize lesion based on examination findings
• Document findings clearly and compare to prior exams