The following set of guidelines has been put together for use by the optometrist. It consists of a list of important neurologic testing procedures which may be useful in the evaluation of patients who present with neuro-ophthalmic signs and symptoms. It is not a substitute for a comprehensive neurologic examination as would be performed by a neurologist, but rather, should serve as a localizing guideline for those clinicians who are frequently faced with manifestations of nuerologic disease.

Parts of the Neurologic Examination

1. Mental Status Assessment
2. Cranial Nerve Assessment
3. Motor Function
4. Reflexes
5. Coordination
6. Sensory Assessment

The mental srarus examination emphasizes cognitive fuction and memory, particularly recent memory, which tends to disappear before long-term memory in organic brain syndromes. The mental status assessment begins with the history. When taking the history, the examiner should note the patient's level of alertness and how appropriate or meaningful the responses are. Often times, information obtain from a family member is more meaningful than that provided by the patient. For example, a patient of previously high intelligence may have dropped off substantially in IQ and still appear normal to the examiner. Furthermore, patients with true dementias often deny that there is a problem. Information from a family member or friend would alert the examiner that a problem does, in fact, exist.

If the examiner determines that the patient responds appropriately during the history, further mental status assessment may not be necessary. It however, the patient's responses indicate a dementia, further testing can proceed as follows:

Alertness

Ask the patient to name the year, month and day and to tell you where he is at the current moment. The patient should also be able to report some general information including name, address and important current events such as who the current president is.

Concentration

Short-term memory is tested by asking the patient to spell a five letter word and then to spell it backwards. Spelling it establishes that the patient can spell. Spelling it backwards requires intact short-term memory. You can quantify this by using shorter words. If the patient cannot spell, counting backwards from 100 by sevens (100, 93, 86 …) can be substituted or the patient can be asked to repeat a seven digit number. To test intermediate memory, the patient is asked to repeat the names of three objects (i.e., coffee, taxi, telephone) and recall them several minutes later.

Reasoning

The patient is asked to explain the meaning of certain proverbs such as "a stitch in time saves nine" or "the grass is always greener on the other side of the fence".
Interpretation

Mental status and cognitive function are governed by the frontal lobes. Deficits in these areas are frequently seen in dementias, head trauma and stroke.

Cranial Nerve I--Olfactory Nerve

Testing should be done with a mild, non-irritating aroma. Tobacco and mild soaps or spices are ideal. Irritating agents such as alcohol or ammonia should not be used because they stimulate the intranasal pain endings of the trigeminal nerve rather than the olfactory nerve. Each nostril should be tested separately with at least two different agents. The patient closes his eyes and is asked to identify the fragrance.
Since testing of this nerve rarely reveals significant pathology of the central nervous system, results are often more confusing than helpful. An abnormal response of often due to a blocked nasal passage or a normal decline in the sense of smell due to aging. It should be included in a screening examination if there is evidence of frontal lobe disease (change in personality or hemiparesis) or if there is unexplained optic nerve disease (the olfactory nerves run very close to the optic chiasm and optic nerves).

Cranial Nerves II, III, IV and VI are all important to normal ocular function and are tested as part of the routine eye examination. Testing of these nerves is briefly summarized below:

Cranial Nerve II-Optic Nerve

Tests of optic nerve function include visual acuity, visual fields, pupils color -vision. Ophthalmoscopy is also important as signs of optic nerve disease include optic atrophy, disc swelling and anomalous vasculature.

Cranial Nerve III--Oculomotor Nerve

Test motility, pupils and observe eyelid position. Third nerve palsy is characterized by limitations of elevation, depression and adduction as well as ptosis and impaired pupillary response to light and near.

Cranial Nerve IV-Trochlear Nerve

Motility is tested. Fourth nerve palsy is characterized by impairment of depression when the eye is adducted.

Cranial Nerve VI--Abducens Nerve

Motility is tested. Sixth nerve palsy is characterized by an abduction deficit.

Cranial Nerve V--Trigeminal Nerve

Motor Component-Muscles of mastication
Instruct the patient to clench his teeth. Palpate the masseter and temporalis muscles. A perceived weakness indicates a reduction in motor function. Next, the patient opens his mouth slowly. Unilateral weakness results in a deviation of the jaw to one side.

Sensory Component-Face, scalp, teeth, sinuses jaws and eyes
The three divisions of the trigeminal nerve are tested separately. Lightly touch both sides of the forehead (opthalmic division or V-1), cheeks (maxillary division or V-2) and chin (mandibular division or V-3) with a cotton-tipped applicator. The patient reports any perceived difference on one side relative to the other. The same areas are then tested for pain sensation by lightly touching them with either the sharp or dull parts, of a safety pin and asking the patient whether it feels sharp or dull. The corneal reflexes are tested by lightly touching the cornea with the wisp of a cotton-tipped applicator. The normal response is a blink and requires that the trigeminal nerve and both facial nerves are intact.

Cranial Nerve VII--Facial Nerve

Function of this nerve is screened by evaluating the muscles of facial expression
in the following manner:
1. Ask the patient to smile and observe for symmetry of the lower facial muscles.
2. Ask the patient to puff his cheeks or whistle
3. Ask the patient to dose his eyes and observe the degree of closure on both sides.
4. Ask the patient to raise his eyebrows and observe the contraction of the frontralis (brow wrinkling).
Supranuclear or upper motor neuron lesions of the facial nerve win cause contralateral weakness of the mouth but not the forehead. In peripheral facial palsies (Bell's Palsy) there is total facial paralysis on one side.

Cranial Nerve VIII--Acoustic Nerve
This cranial nerve has two components that originate in the brainstem and travel to the inner ear. The vestibular component ties information from the semicircular canals to cerebellar and cortical locations regarding balance. The cochlear component transmits signals from the cochlea to the temporal lobes for hearing sense.

Testing of the cochlear component is simply done by rubbing the thumb and fingers together at either ear of the patient. If the patient reports relative asymmetry, determine whether the relative hearing loss is due to a conduction deficit or a sensorineuronal deficit. This is easily accomplished by instructing the patient to hum. If the humming is heard louder in the ear with the hearing loss, the deficit is presumed to be a conduction deficit such as ear wax, otitis media or damaged drum or ossicle. If the humming is louder in the normal ear, the hearing deficit is presumed to be sensorineuronal and damage to the nerve is presumed.

The vestibular component is tested in the coordination part of the neurologic screening.

Cranial Nerves IX and X--Glossopharyugeal and Vagus Nerves

The motor components of these nerves are tested in the neurologic screening. The glossopharyngeal nerve has a motor component to the muscles of the pharynx and the vagus has a motor component to the muscles of the larynx and pharynx. Because their motor functions are closely related, they are tested together.

Listen to the patient's voice and note any -hoarseness or problems with speaking. Next, the patient is instructed to open his mouth and say "ahh" while the examiner depresses the tongue with a tongue depressor. Symmetric elevation of the soft palate should occur with midline elevation of the uvula. The gag reflex is tested by touching the soft palate or pharyngeal wall with a cotton applicator. This is an unpleasant test which can generally be avoided as compromise to these nerves is extremely rare.

Cranial nerve XI--Accessory nerve

This nerve has a cranial root which joins with the vagus nerve and a spinal root which innervates the sternocleidomastoid and trapezium muscles. It is rarely injured except in neck injuries. To test trapezium strength, the patient is instructed to raise his shoulders against the manual resistance of the examiner. To test sternocleidomastoid strength, the patient is instructed to turn his head laterally against the manual resistance of the examiner.

Cranial Nerve XII--Hypoglossal Nerve

The hypoglossal nerve has a motor component to the muscles of the tongue. Function is assessed by instructing the patient to stick out his tongue while the examiner observes for asymmetry. If there is weakness on one side, the tongue will deviate to the side of the weakness. Next, the patient is instructed to push his tongue into his cheek while the examiner palpates the cheeks for tone and strength of the tongue.

Motor strength in neurologic screening for optometrists is confined to testing for relative differences in tight versus left sided strength of the upper and lower extremities.

Upper Extremity Drift

Ask the patient to close his eyes and extend his arms straight ahead with the palms facing upward and observe for 20-30 seconds. If there is weakness on one side, the hand on the affected side will drift and rotate inward (pronator drift).

Other Tests of Motor Strength

The examiner grasps the patient's right hand with his right hand. The patient is instructed to push his arms away and then toward his body against the resistance of the examiner. This is repeated on the left side. Next the lower extremity is tested by instructing the seated patient to lift his knee up against the examiner's resistance and to pull his lower leg toward and then away from the examiner while the examiner grasps the ankle and applies resistance.
Contralateral hemiparesis is seen in intracranial lesions that affect the motor cortex of the frontal lobe, internal capsule and brainstem.

The major reflexes are the biceps, triceps, knee jerk, ankle jerk and Babiniski. In order to ellicit good responses, the reflex hammer should be held loosely between the fingers and the examiner should strike the appropriate tendon firmly. It is also important that the patient is relaxed. The appropriate tendon is tapped lightly but firmly with reflex hammer.

Triceps

The arm is placed across the chest with the elbow at a ninety degree angle. The examiner strikes the triceps tendon just above the elbow and observes the contradiction of the triceps muscle with extension at the elbow.

Biceps

The patient's hands are placed on his abdomen. The examiner's index finger is placed on the biceps tendon at the elbow. The hammer is swung directly onto the finger while observing the biceps muscle for contraction and flexion at the elbow.

Knee Jerk

The patient is seated with the knees at a ninety degree angle. The patellar tendon is struck directly, just below the patella. The quadriceps muscle in the thigh is observed or felt through a heavily clothed patient for contraction, or, leg extension at the knee is observed.

Ankle Jerk

The foor is held ar ninety degrees. The achilles tendon is struck directly and the calf muscle are observed for contraction.

A normal person may exibit a wide range of reflexes from active to absent, therefore, asymmetric responses are more important indicators of pathology. Increased reflexes are seen in upper motor neuron lesions while reduced or absent reflexes are seen in lower motor neuron disease peripheral neuropathies. Disorders of neuro-ophthalmic significance are more likely to result in upper motor neuron deficits with increased reflexes. A disorder that commonly results in decreased or absent tendon reflexes is Adie's tonic pupil.

Babinski Reflex (Plantar response)

Shoes and socks are removed. The foot is elevated and supported with the examiner's hand or knee. The examiner gently but firmly draws a pointed object such as the end of a wooden cotton-tipped applicator up the lateral portion of the bottom of the foot from the heel forward and across the foot pad. A normal response is plantar flexion of the toes. A positive result is dorsiflexion of the big toe with a fanning out or spreading of the other toes and indicates upper motor neuron disease.

The structures that play an important role in coordination are the cerebellum as basal ganglia. In addition, balance is important to coordination and therefore, vision, proprioception and vesticular sense are assessed when testing coordination as they all feed directly into the cerebellum.

Finger to Nose Test

The patient closes his eyes and extends his arms out at his sides and parallel to the floor. The patient is instructed to alternately touch his right and left index fingers to his nose quickly and repetitively in succession.

Heel to Shin

The seated patient is instructed to place his right heel on his shin at the knee and move in down the length of the shin to the ankle and back up to the knee again. The same is repeated on the opposite side.

Rapid Alternating Hand and Foot Movements

The patient is instructed to alternately touch his thumb with each finger tip or to rapidly flip-flop one hand while it rests on the other. Rapid foot movements are ellicited by instructing the patient to rapidly tap his foot to the floor while the heels rests in place.

On finger to one and heel to shin testing, cerebellar dysfunction if indicated when the finger over or undershoots its target (dysmetria) or when a tremor develops as the finger approaches its target. If a tremor improves with movement and is more apparent at rest (resting tremor) basal ganglia disease is suggested (Parkinson's). On heel-to-shin testing, cereberall dysfunction is indicated when the heel falls off the shin or if the knee wobbles from side to side. Difficulty on rapid alternating hand and foot movements is indicative of ipsilateral cerebellar disease.

Testing Balance

Tandem gait and the Romberg test are key tests for balance. To test tandem gait, the patient is instructed to walk placing one foot directly in front of the other, heel-to-toe. Normal patients are able to walk without swaying. The Romberg rest is simply tandem walking that is done with the eyes closed and this is done when tandem walking is normal.

If the patient has difficulty performing tandem walking with the eyes open, cerebellar disease is indicated. If proprioception is lacking, the patient will keep his balance with the eyes open but not with the eyes closed. This occurs because vision, vesticular sense and proprioception, all of which have cerebellar connections, are involved in balance and two of the three must be functioning normally to maintain balance. The Romberg test iliminates visual input, therefore, if a patient cannot tandem walk with the eyes closed, proprioception or vestibular sense must be faulty. Vestibular disease is suspected when the patient complains of vertigo and is typically manifested by nystagmus. If the patient has no vertigo or nystagmus, proprioception must be faulty.

Intracranial lesions of the cerebrum or brainstem will typically result in generallized sensory losses of the contralateral upper and lower extremities. Therefore in patients with neuro-ophthalmic disease, it is only necessary to do a gross sensory examination of the face hands and feet. Sensory evaluation consists of testing of the primary sensory modalities which include pain, proprioception, vibration and light touch.

Pain

The patient is seated with eyes closed, hands in lap and palms down. The examiner places a sharp stimulus on the dorsum of each and asks the patient if it feels sharp or dull. The same is repeated with the dorsum of each foot and on either side of the face. A broken stick of a cotton-tipped applicator is ideal because it can be discarded after each patient.

Temperature

Ask the patient if an ophthalmoscope handle feels cool or warm when touched to the hands, feet and cheeks. Likewise, a wooden tongue depressor will be perceived as a warm stimulus.

Proprioception/Position

With the patient's eyes closed, the big toe is grasped from the sides to avoid clues ellicited by pressure. The toe is bent upwards or downwards and the patient is asked to report whether the toe is "up" or "down". Testing of the upper extremity is unnecessary if the lower extremity is normal.

Light Touch

If pain and proprioception are intact, it is not necessary to test light touch as it is unlikely to be affected. Double, simultaneous stimulation of the dorsum of the hands, feet and cheeks is done with a cotton wisp and the patient compares the sensation on either side.

Brainstem lesions produce hemisensory deficits on the ipsilateral side of the face and contralateral upper and lower extremities. Parietal disease and thalamic lesions result in hemisensory deficits of the contralateral face, upper and lower.