Cranial Nerves and Cerebellar Function Tests

PEERLA Dermatomes

• Dermatomes refer to specific areas of skin supplied by a single spinal nerve
• Cervical Dermatomes: correspond to the neck and upper shoulders
• Lumbar Dermatomes: correspond to the lower back and buttocks
• Thoracic Dermatomes: correspond to the chest and abdomen

Whisper Test

• Screening test used to assess hearing acuity
• Involves whispering a set of words or numbers at a consistent volume from a specific distance behind the patient
• Evaluates the patient's ability to hear whispered sounds

Resting Tremors vs. Intentional Tremors

• Resting Tremors: occur when muscles are at rest, often associated with conditions like Parkinson's disease
• Intentional Tremors: occur during voluntary movement, may indicate conditions like essential tremor

Tinnitus

• Perception of noise or ringing in the ears without an external source
• Can be subjective (only the patient hears it) or objective (both the patient and examiner can hear it)

Aura

• Sensory disturbances that often precede a migraine headache
• Can manifest as visual, sensory, or motor symptoms

Clonus

• Rhythmic, involuntary muscular contraction and relaxation in response to sudden stretching of a muscle
• Often associated with upper motor neuron lesions

Nystagmus

• Involuntary, rhythmic movements of the eyes that can occur horizontally, vertically, or rotatory
• Can indicate vestibular dysfunction or neurological abnormalities

Vertigo

• Sensation of spinning or dizziness, often described as feeling off-balance or as if the surrounding environment is moving
• Can be caused by inner ear problems, neurological issues, or other systemic conditions

Snellen Eye Chart

• Chart used to measure visual acuity
• Patients are asked to read letters or symbols from a distance, with their vision assessed relative to what a person with normal vision can see at that distance

Screening/Recheck/Complete Examination

• Screening: initial assessment to identify potential health issues or abnormalities
• Recheck: follow-up assessment to monitor changes or progress in a condition
• Complete Examination: thorough assessment covering all aspects of a patient's health, including history-taking, physical examination, and diagnostic testing as needed

Sinusitis

• Inflammation or infection of the paranasal sinuses, which can cause symptoms such as facial pain, pressure, nasal congestion, and headache

Cerumen

• Earwax produced by glands in the ear canal
• Can accumulate and cause hearing impairment or discomfort if not removed

Romberg Test

• Neurological test used to evaluate balance and proprioception
• Patient stands with feet together and eyes closed to assess the ability to maintain balance without visual input

Presbyopia

• Age-related loss of near vision due to decreased flexibility of the lens in the eye
• Commonly occurs in individuals over the age of 40

Anisocoria

• Condition characterized by unequal pupil sizes
• Can be benign or indicative of underlying neurological or ophthalmological issues

Glasgow Coma Testing

• Assessment tool used to evaluate a patient's level of consciousness following a traumatic brain injury or other neurological event
• Assesses eye opening, verbal response, and motor response to assign a numerical score

Different Forms of Hearing Loss

• Conductive Hearing Loss: caused by problems in the outer or middle ear
• Sensorineural Hearing Loss: caused by damage to the inner ear or auditory nerve
• Mixed Hearing Loss: combination of conductive and sensorineural hearing loss
• Central Hearing Loss: caused by damage to the central auditory pathways in the brain

Cranial Nerves

• CN I: Olfactory nerve (smell test)
• CN II: Optic nerve (visual acuity and fields test)
• CN III: Oculomotor nerve (pupillary response, EOMs)
• CN IV: Trochlear nerve (EOMs, especially downward gaze)
• CN V: Trigeminal nerve (facial sensation, muscles of mastication)
• CN VI: Abducens nerve (lateral gaze)
• CN VII: Facial nerve (facial movements, taste anterior 2/3 tongue)
• CN VIII: Vestibulocochlear nerve (hearing and balance tests)
• CN IX: Glossopharyngeal nerve (gag reflex, taste posterior 1/3 tongue)
• CN X: Vagus nerve (gag reflex, voice quality, visceral reflexes)
• CN XI: Spinal Accessory nerve (shoulder shrug, head turn against resistance)
• CN XII: Hypoglossal nerve (tongue movement)

EYE ASSESSMENT

• Nystagmus: involves CN VIII (vestibulocochlear nerve), but also relates to CN III (oculomotor nerve), CN IV (trochlear nerve), and CN VI (abducens nerve)
• Abnormal finding: involuntary rhythmic shaking or oscillation of the eyes### Neurological Assessment
• Corneal Reflex: Tested by gently touching the cornea with a cotton swab; abnormal finding is absence or asymmetry of the blinking response (CN V: trigeminal nerve for sensory input and CN VII: facial nerve for motor response)

Cerebellar Function Tests

• Balance Test: Abnormal findings include loss of balance, unsteady gait, inability to walk straight, or requiring a wide base to stand
• Romberg Test: Abnormal findings include swaying or falling when eyes are closed, indicating proprioceptive or vestibular dysfunction
• Tests for Coordination and Skilled Movements:
  • Rapid Alternating Movements (RAM): Tests cerebellar function, specifically the ability to perform rapid, alternating movements smoothly
  • Finger-to-Nose Test: Tests coordination and precision of movements, pointing to cerebellar function or proprioceptive feedback
  • Heel-to-Shin Test: Tests lower limb coordination and the ability to perform smooth, accurate movements

Sensory Examination

• Tactile Discrimination (Fine Touch):
  • Stereognosis: Normal finding is the ability to recognize and identify common objects by touch and manipulation without the use of vision; abnormal finding is inability to recognize objects by touch
  • Graphesthesia: Normal finding is the ability to recognize writing on the skin purely by the sensation of touch; abnormal finding is difficulty in recognizing writing on the skin
  • Two-point Discrimination: Normal finding is the ability to discern two distinct points when they are applied simultaneously at close proximity on the skin; abnormal finding is inability to distinguish two nearby points touching the skin
  • Extinction: Normal finding is the ability to perceive touch on one side when both sides are touched simultaneously; abnormal finding is failure to perceive touch on one side when both sides are touched simultaneously
  • Point Location: Normal finding is the ability to accurately indicate where they were touched; abnormal finding is difficulty in identifying the exact point on the body that was touched

Reflexes

• DTRs (Deep Tendon Reflexes):
  • 4-Point Scale:
    • 4: Very brisk, hyperactive with clonus, indicative of disease
    • 3: Brisker than average, may indicate disease
    • 2: Average, normal
    • 1: Diminished, low normal, or occurs with reinforcement
    • 0: No response
  • Nerve Tracts Tested: These reflexes test the integrity of the spinal cord segments and corresponding nerve tracts; they are monosynaptic reflex arcs
  • Body Areas Tested: Common sites include the biceps (C5-C6), triceps (C6-C7), brachioradialis (C5-C6), patellar (L2-L4), and Achilles (S1-S2)
• Superficial Reflexes:
  • Abdominal Reflexes: Normal finding is contraction of the abdominal muscles and movement of the umbilicus towards the stimulus when the skin of the abdomen is lightly stroked; abnormal finding is absence of contraction of the abdominal muscles and movement of the umbilicus
  • Cremasteric Reflex: Normal finding is brisk elevation of the testicle on the same side when the upper inside of the thigh is stroked; abnormal finding is lack of elevation of the testicle on the side stroked
  • Plantar Reflex, L4 to S2: Normal finding is downward flexion of the toes when the sole of the foot is stimulated with a blunt object; abnormal finding is extension of the big toe with fanning of the other toes (Babinski sign)

Head and Face Assessment

• Inspecting the Head and Face:
  • Procedure: Observe the size, shape, and contour of the skull; note any deformities, lumps, or tenderness
  • Expected Findings: Symmetrical head and face, with no visible lesions or deformities
  • Abnormal Findings: Asymmetry, lumps, depressions, or abnormal protrusions

Ear and Hearing Assessment

• Inspecting the Ears:
  • Tragus: A firm protrusion of cartilage on the outside of the ear; tenderness here can indicate infection
  • Auricle: The external part of the ear; should be symmetrical with no lesions or deformities

Whispers Test

• Definition: A screening test used to assess hearing acuity
• Procedure: Whisper a set of words or numbers at a consistent volume from a specific distance behind the patient to evaluate their ability to hear whispered sounds### Cranial Nerve Function Tests
• Corneal Reflex: tests CN V (trigeminal nerve) for sensory input and CN VII (facial nerve) for motor response (blinking)
• Abnormal finding: absence or asymmetry of the blinking response

Cerebellar Function Tests

• Balance Test: loss of balance, unsteady gait, inability to walk straight, or requiring a wide base to stand
• Romberg Test: swaying or falling when eyes are closed, indicating proprioceptive or vestibular dysfunction
• Rapid Alternating Movements (RAM): tests cerebellar function, specifically the ability to perform rapid, alternating movements smoothly
• Finger-to-Nose Test: tests coordination and precision of movements, pointing to cerebellar function or proprioceptive feedback
• Heel-to-Shin Test: tests lower limb coordination and the ability to perform smooth, accurate movements

Sensory Function Tests

• Tactile discrimination (fine touch) Stereognosis: ability to recognize and identify common objects by touch and manipulation without the use of vision
• Abnormal finding: inability to recognize objects by touch
• Graphesthesia: capacity to recognize writing on the skin purely by the sensation of touch
• Abnormal finding: difficulty in recognizing writing on the skin purely by the sensation of touch
• Two-point Discrimination: ability to discern two distinct points when they are applied simultaneously at close proximity on the skin
• Abnormal finding: inability to distinguish two nearby points touching the skin
• Extinction: failure to perceive touch on one side when both sides are touched simultaneously
• Point Location: ability to accurately indicate where they were touched after a point on the skin is touched and the stimulus is removed
• Abnormal finding: difficulty in identifying the exact point on the body that was touched

Reflexes

• Deep Tendon Reflexes (DTRs) 4-Point Scale:
  • 4: very brisk, hyperactive with clonus, indicative of disease
  • 3: brisker than average, may indicate disease
  • 2: average, normal
  • 1: diminished, low normal, or occurs with reinforcement
  • 0: no response
• Myotatic Reflexes:
  • Nerve Tract: tests the integrity of the spinal cord segments and corresponding nerve tracts
  • Body Areas Tested: biceps (C5-C6), triceps (C6-C7), brachioradialis (C5-C6), patellar (L2-L4), and Achilles (S1-S2)
• Superficial Reflexes:
  • Nerve Tract: tests the function of higher brain centers and the spinal cord
  • Body Areas Tested: abdominal reflexes (T8-T12), cremasteric reflex (L1-L2), and plantar reflex (L5-S1)
• Visceral Reflexes:
  • Nerve Tract: tests the autonomic nervous system and involves smooth muscle responses rather than skeletal muscle
  • Body Areas Tested: pupillary response to light (optic nerve for sensory input and oculomotor nerve for motor response) and reflexes controlling bowel and bladder functions
• Pathologic Reflexes:
  • Clonus: indicates disruption of motor tracts, typically within the central nervous system
    • Body Areas Tested: often tested at the ankles, where rapid flexion and extension of the foot can elicit rhythmic oscillations (clonus)
  • Dyskinesia: represents a dysfunction in the basal ganglia circuits, which are responsible for the regulation of voluntary motor movements and procedural learning
    • Body Areas Tested: it is not a specific reflex test but is assessed through observation of the movements of the limbs or body, typically presenting as a series of involuntary muscle movements

Reflex Testing Procedures

• Biceps Reflex: tests C5-C6; normal response is contraction of biceps muscle and flexion of forearm
• Triceps Reflex: tests C7-C8; normal response is extension of forearm
• Brachioradialis Reflex: tests C5-C6; normal response is flexion and supination of forearm
• Quadriceps Reflex: tests L2-L4 ("knee jerk"); normal response is extension of lower leg
• Achilles Reflex: tests L5-S2 ("ankle jerk"); normal response is foot plantar flexes against your hand
• Abdominal Reflexes: normal finding is contraction of the abdominal muscles and movement of the umbilicus when the skin of the abdomen is lightly stroked
• Cremasteric Reflex: normal finding is brisk elevation of the testicle on the same side when the upper inside of the thigh is stroked
• Plantar Reflex: normal finding is downward flexion of the toes when the sole of the foot is stimulated with a blunt object

Headaches

• Dizziness: sensation of lightheadedness, faintness, or unsteadiness that does not involve the sensation of movement
• Vertigo: type of dizziness where there is a sensation of spinning or movement, either of oneself or the surroundings
• Tension Headache: dull, aching head pain and tightness or pressure across the forehead or on the sides and back of the head
• Migraine: intense, debilitating headaches accompanied by symptoms such as nausea, vomiting, difficulty speaking, numbness or tingling, and sensitivity to light and sound
• Cluster Headache: severe headaches on one side of the head, often around the eye, accompanied by symptoms such as red or teary eyes, runny or stuffy nose, and flushing or sweating of the face

Inspection of the Head and Face

• Procedure: observe the size, shape, and contour of the skull, noting any deformities, lumps, or tenderness
• Expected findings: symmetrical head and face, with no visible lesions or deformities
• Abnormal findings: asymmetry, lumps, depressions, or abnormal protrusions

Pupillary Tests

• Accommodation: ability of the eye to change its focus from distant to near objects (and vice versa)
• Direct Response: pupil constriction when light is shone directly into the eye
• Consensual Response: simultaneous constriction of the opposite pupil when light is shone into one eye
• PERRLA: pupils equal, round, and reactive to light and accommodation, indicating normal function
• Corneal Light Reflex: reflection of light from the cornea, which should be in the same spot on each eye, indicating alignment

Inspection of the Nose

• Procedure: visual inspection of the external nose for symmetry, deformities, or lesions; internal examination for mucosa color, septum deviation, or polyps
• Expected findings: symmetrical alignment, pink mucosa, no discharge, and patent nares
• Abnormal findings: deviated septum, polyps, or unusual nasal discharge

Inspection of the Ears

• Tragus: firm protrusion of cartilage on the outside of the ear; tenderness here can indicate infection
• Auricle: external part of the ear; should be symmetrical with no lesions or deformities

Palpation of Lymph Nodes

• Occipital: located at the base of the skull; palpable nodes may indicate an infection or other head/neck pathology
• Posterior auricular: located behind the ear; enlargement may indicate local infection
• Preauricular: in front of the ear; swollen nodes may suggest infection in the eye, ear, or face
• Tonsillar (Jugulodigastric): under the angle of the mandible; often enlarged with pharyngeal or oral infections
• Submandibular: halfway between the angle and the tip of the mandible; enlargement can occur with infections of the head, neck, sinuses, ears, eyes, scalp, or pharynx
• Submental: midline, behind the tip of the mandible; may enlarge with infections of the lower lip, the floor of the mouth, or the tip of the tongue