The basic neurological

examination

Dr. Szathmári Miklós

Semmelweis University

First Department of Medicine

07. Dec. 2015.

The neurological examination

• Mastery of the complete neurological

examination is usually important only for

physicians in neurology

• However, knowledge of the basics of the

examination, especially those component that

are effective in screening for neurological

dysfunction is essential for general physicians

• A screening examination done in the suggested

way lasts 3-5 min.

Major areas of the neurological exam

• Mental status testing

• Cranial nerves

• Muscle strength, tone and bulk

• Reflexes

• Coordination

• Sensory Function

• Gait

Mental status examination

• During the interview, look for difficulties with communication and determine whether the patient has recall and insight into recent and past events.

• If the history raises any concern for abnormalities of higher cortical function or if cognitive problems are observed during the interview, then detailed testing of the mental status is indicated.

Elements of mental status

examination

• Level of consciousness– The patient’s relative state of awareness of the self

and the environment (ranged: fully awake-comatose).

– The doctor has to describe the responses to the minimum stimulus necessary to elicit a reaction.

– Loss of oculocephalic reflex (doll’s eye movements) in a comatose patient suggest a lesion of midbrain or pons (Holding open the upper eyelids turn the head quickly, first to one side and than to the other. Normally the eyes move in the opposite direction as if still gazing ahead in their initial position).

• Orientation– Is tested by asking to state his or her name, location

and time

Level of consciousness

– Is the patients awake and alert?

– Does the patient seem to understand your questions and respond appropriately or is there a tendency to lose track of the topic and fall silent or even sleep? If the patient does not respond, escalate the stimulus in steps:

• Speak to the patient in a loud voice

• Shake the patients gently

• Brief painful stimulus such as squeeze of the trapezius muscle)

• If there is no response that means severe reductions in the level of consciousness (stupor or coma)

Elements of mental status

examination

• Speech– Articulation, rate, rhythm, etc.

• Memory– Immediate memory: saying a list of three items, and the patient

repeat the list immediately

– Short-term memory: to recall the same items 10 min later

– Long-term memory: how well the patient is able to provide a coherent chronologic history of his or her personal events

• Abstract thought– Can be tested by asking the patient to list items having the same

attributes (e.g. a list of four-legged animals)

• Calculation ability– Serial subtraction 7 from 100 or 3 from 20

Cranial nerve examination

• The bare minimum: check – the visual fields

– the pupil size

– the pupil reactivity

– the extraocular movements

– the facial movements

• Bulbar paralysis: lesion of the IX-XII. cranial nerves: disturbance of swallowing, breathing and dysarthria, and atrophy of the tongue.

• Pseudobulbar paralysis: the same except of the tongue atrophy.

Cranial nerve examination 1.

• CN I.(olfactory) – Testing is usually omitted unless there is suspicion for inferior frontal lobe disease (e.g. meningeoma)

– With eyes closed, ask the patient to sniff a mild stimulus such as toothpaste or coffee and identify odorant.

– Symptoms: hyposmia, anosmia

• CN II.(optic)- Checking visual acuity and testing the visual fields by confrontation, by comparing the patient’s visual fields to your own.

– A Snellen Chart is the standard, wall mounted device used for this assessment. Patients are asked to read the letters or numbers on successively lower lines (each with smaller images) until you identify the last line which can be read with 100% accuracy. Each line has a fraction written next to it. 20/20 indicates normal vision. 20/400 means that the patient's vision 20 feet from an object is equivalent to that of a normal person viewing the same object from 400 feet. In other words, the larger the denominator, the worse the vision.

– Face the patient at a distance of appr. 0.6-1.0 m and place your hands at the periphery of your visual fields in the plane that is equidistant between you and the patient. Instruct the patient to look directly at the centre of your face and to Indicate when and where he or she sees one of your finger moving.

– Pupils: The pupil has afferent (sensory) nerves that travel with CN2. These nerves carry the impulse generated by the light back towards the brain. They function in concert with efferent (motor) nerves that travel with CN 3 and cause pupillary constriction.

Normally, the eyes move in

concert (ie when left eye

moves left, right eye moves in

same direction to a similar

degree). The brain takes the

input from each eye and puts

it together to form a single

image. This coordinated

movement depends on 6 extra

ocular muscles that insert

around the eye balls and allow

them to move in all directions.

Each muscle is innervated by

one of 3 Cranial Nerves

(CNs): CNs 3, 4 and 6.

CN 4 (Trochlear): Controls the Superior Oblique muscle.

CN 6 (Abducens): Controls the Lateral Rectus muscle.

CN 3 (Oculomotor): Controls the remaining 4 muscles (inferior oblique, inferior

rectus, superior rectus, and medial rectus). CN3 also raises the eyelid and

mediates constriction of the pupil.

Pupil reactions

• Using any light source (flashlight, oto-ophtahlmoscope, etc), shine the light

into one eye. This will cause that pupil to constrict, referred to as the direct

response.

• Remove the light and then re-expose it to the same eye, though this time

observe the other pupil. It should also constrict, referred to as the

consensual response. This occurs because afferent impulses from one

eye generate an efferent response (i.e. signal to constrict) that is sent to

both pupils.

• If the patient's pupils are small at baseline or you are otherwise having

difficulty seeing the changes, take your free hand and place it above the

eyes so as to provide some shade. This should cause the pupils to dilate

additionally, making the change when they are exposed to light more

dramatic. If you are still unable to appreciate a response, ask the patient to

close their eye, generating maximum darkness and thus dilatation. Then

ask the patient to open the eye and immediately expose it to the light. This

will (hopefully) make the change from dilated to constricted very apparent.

Interpretation of pupil reactions

• Under normal conditions, both pupils will appear symmetric. Direct and consensual

response should be equal for both.

• Asymmetry of the pupils is referred to as anisocoria. Some people with anisocoria

have no underlying neuropathology.

• A number of conditions can also affect the size of the pupils.

Medications/intoxications which cause generalized sympathetic activation will result

in dilatation of both pupils. Other drugs(e.g. narcotics) cause symmetric constriction

of the pupils. These findings can provide important clues when dealing with an

agitated or comatose patient suffering from medication overdose. Additionally, any

process which causes increased intracranial pressure can result in a dilated pupil that

does not respond to light.

• If the afferent nerve is not working, neither pupil will respond when light is shined in

the affected eye. Light shined in the normal eye, however, will cause the affected

pupil to constrict. That's because the efferent (signal to constrict) response in this

case is generated by the afferent impulse received by the normally functioning eye.

This is referred to as an afferent pupil defect.

• If the efferent nerve is not working, the pupil will appear dilated at baseline and will

have neither direct nor consensual pupillary responses.

Cranial nerve examination 2.

• CN VII (facial) - look for facial asymmetry at rest and with spontaneous movement

– Eyebrow elevation, forehead wrinkling, eye closure, smiling and cheek puff

– Weakness of the lower two-third of the face with preservation of upper third suggest an upper motor neuron lesion

– Weakness of an entire side suggest a lower motor neuron lesion.

• CN VIII (vestibulocochlear) – Check the patient’s ability to hear a finger rub or whispered voice with each ear

– Further testing for air versus mastoid bone conduction etc. Should be done if an abnormality is detected by history or examination.

• CN IX, X (glossopharyngeal, vagus) – Observe the position and symmetry of palate and uvula at rest and with phonation („aah”)

– Symptoms of injury: paresis of the palate, nasal voice, disturbance with swallow, hoarseness.

• CN XI (spinal accessory)– Check shoulder shrug (trapezius muscle) and head rotation to each side

(sternocleidomastoid) against resistance

• CN XII (hypoglossal)– Inspect the tongue (in case of the unilateral paresis the tongue deviates in the

direction of the normal side) for atrophy or fasciculation, position, and strength when extended against the inner surface of the cheeks on each side

Motor examination 1.

• Observation of muscle– Appearance

• Inspection and palpation of muscle group with patient in a comfortable and symmetric position

• Check atrophy, hypertrophy and tenderness

• Involuntary movements

– present at rest: myoclonus, tics

– during maintained posture: pill-rolling tremor of Parkinson’s disease

– with voluntary movements: intention tremor of cerebellar disease, etc.

– Tone is tested by measuring the resistance to passive movement of relaxed limb.

• While the patient is supine the examiner’s hand are placed behind the knees and rapidly raise. With normal tone the ankles are drag along the table surface for a variable distance before rising

– Increased tone results in an immediate lift of the heel off the surface

– Cogwheel rigidity: in which passive motion elicits jerky interruptions in resistance, is seem in parkinsonism

Motor examination 2.

• Observation of the muscle strength– Pronator drift method: the patient is asked to hold

both arms fully extended and parallel to the ground with eyes closed. This position should be maintained for 20-30 sec.

• Any flexion at the elbow or fingers or pronation of the forearm, especially if asymmetric, is a sign of potential weakness.

– Examination of active movements• Example: test flexion at the hip: by placing your hand on the

patient’s thigh and asking the patient to raise the leg against it

– Paralysis: no movement

– Severe weakness: movement with gravity eliminated

– Moderate weakness: movement against gravity but not against mild resistance

– Mild weakness: movement against moderate resistance

– Full strength

Motor examination 3.

• Muscle stretch reflexes

– Biceps (C5,6), triceps (C7,C8), patellar (L3,4),

and Achilles (S1,S2)

– The patient should be relaxed and the muscle

positioned midway between full contraction

and extension

– Reflexes may be enhanced by asking the

patient to voluntarily contract other, distant

muscle group (JENDRASSIK’S MANEUVER)

Sensory examination

• Pain and temperature, impulses for which are

carried in the spinothalamic tracts of the cord

• Position and vibration, impulses for which are

carried in the posterior columns

• Light touch, impulses for which are carried

along both of these pathways

• Discriminative sensations, which depend on

some of the above sensations but also require

cortical judgments

Screening of sensory system

• Pain sensation in the hand and the feet– It is tested using a sharp safety pin

– Anelgesia-hypalgesia-hyperalgesia

• Light touch– It is assessed with single, very gentle touch of the examiner’s finger

– Anaesthesia – absence of touch sensation, hypaesthesia -decreased sensitivity, hyperaesthesia- increased sensitivity

• Vibration – It is tested using 128 Hz tuning fork applied to the distal phalanx of

the great toe

• Temperature– It is assessed using a metal object that has been immersed in a cold

and warm water

• Discriminative sensation– Such as graphaesthesia –with a blunt end of a pen, draw a large

number in the patient’s palm

Special manoeuvres

• Meningeal sign (in case of suspicion of inflammation of the meninges or bleeding (subarachnoid)– The patient is supine position.

– Place your hand behind the patient’s head and flex the neck forward, until the chin touches the chest. Note resistance or pain. Watch also for flexion of the patient’s hips and knees during the manoeuvre – The name of the positive response is Brudinski’s sign.

– Kernig’s sign: Flex one of the patient’s legs at both hip and knee, then straighten the knee. Unusual resistance or pain – mostly when bilateral – suggests meningeal inflammation

Coordination examination

• Coordination refers to the orchestration and fluidity of movements.

• Part of this integration relies on normal function of the cerebellar and basal ganglia, however, coordination requires intact muscle strength and proprioceptive information

• The minimum testing of cerebellar function:– Finger-to-nose test: the patients is asked to touch his or her

index finger repetitively to the nose and then to the examiner’s outstretched finger, which moves with each repetition.

– Heel-knee-shin manoeuvre: in the supine position the patient is asked to slide the heel of each foot from the knee down the shin of the other leg.

• The accuracy, speed, and rhythm are observed.

Gait examination

• Normal gait requires multiple systems – including strength, sensation, and coordination – function in a highly integrated fashion.

• The patient should be observed while walking and turning normally, walking on the heels, on the toes, and walking heel to-toe along a straight line.– Decreased arm swing on one side – corticospinal tract disease

– Short-stepped gait – parkinsonism

– Broad-based unstable gait – ataxia (may be due to cerebellar disease, loss of position sense, or intoxication)

– High-stepped, slapping gait – posterior column or peripheral nerve disease

Localization of damage according to signs

The place of the injury Signs

Cerebrum Abnormal mental state

Unilateral weakness

Visual field abnormalities

Movement abnormalities

Brainstem Cranial nerve abnormalities

Crossed weakness and sensory

abnormalities

Spinal roots Radiating limb pain

Weakness and sensory abnormalities

Peripheral nerve Mid or distal limb pain

Weakness, „stocking or glove” distribution

of sensory loss, loss of reflexes

Neuromuscular junction Bilateral weakness, increasing weakness

with exertion, normal sensory functions

Muscle Bilateral proximal or distal weakness

Sparing of sensation

Harrison’s: Principles of Internal Medicine. 17th Edition. McGraw Hill (modified table)