Neurological examination

Neurological examination is the assessment of mental status, cranial nerves, motor and sensory function, coordination, and gait for the diagnosis of neurological conditions. Findings should always be compared with the contralateral side and upper limb function should be compared with lower limb function to determine the location of a lesion. Subtle central nervous system defects can be detected with careful observation of patients performing tasks that require the simultaneous activation of multiple cerebral areas. This article provides information about several examination methods and explains key terms relevant to the evaluation of neurological conditions.

• The mental status examination is a key component of any neurological examination and involves assessing the following points, based on patient history and clinical observation:
  • Appearance and behavior
  • Sensorium and cognition
  • Mood and affect
  • Speech
  • Thought process
  • Thought content
  • Perceptual disturbances
  • Insight and judgment
• A more focused mental status examination is performed in the workup of specific neurological disorders and symptoms.
• In emergency settings, the mental status examination focuses on the assessment of orientation and level of consciousness using standardized scales (e.g., Glasgow coma scale).
• See “Mental status examination” for a comprehensive discussion of examination elements and possible findings.

• Aphasia is the inability to either form or understand language not attributed to the motor ability to produce speech. It is caused by damage to different areas of the dominant hemisphere (usually left).

The Broca's area is broken in Broca aphasia.
Speech of patients with Wernicke aphasia is like a Word salad
In Conduction aphasia, the arCuate fasciculus is affected.

Overview of cranial nerve examination

The cranial nerve examination is used to identify problems with the cranial nerves by physical examination. For information on disorders of the cranial nerves, see “Cranial nerve palsies.” The assessment includes the following components:

Overview of cranial nerve reflexes

The motor system examination allows to quantify the degree of motor function impairment and often to differentiate between central and peripheral lesions. The fundamental elements of the examination include muscle appearance, muscle strength (power), tone, and reflexes.

In LOWer motor neuron lesions, muscle mass, tone, power, and reflexes are LOW. In UPper motor neuron lesions, muscle tone, reflexes, and toes (Babinski sign) are UP.

Findings ^[1]

• Abnormal muscle movements (see table below)
• Fasciculation
  • Involuntary, asynchronous contraction of muscle fascicles within a single motor unit
  • Usually benign but can signify a lower motor neuron lesion, which results in spontaneous action potentials and/or compensatory increase in the concentration of nicotinic acetylcholine receptors on the cell membrane located at the neuromuscular junction
• Catatonia: abnormal behavior and movement, often including catalepsy, purposeless motor activity, strange postures, negativism, and mutism
• Catalepsy: a state of muscular rigidity and immobility characterized by unresponsiveness to external stimuli
• Grossly disorganized behavior: inadequate goal-directed activity (e.g., purposeless movements) and emotional responses that seem bizarre to others (e.g., smiling or laughing in inappropriate situations)
• Motor stereotypies: rhythmic, repetitive movements; commonly seen in stereotypic movement disorder
• Abnormal posture
• Atrophy or hypertrophy (examined bilaterally)
  • Muscle groups are measured to compare specific differences in size.
  • In neurologic disorders with lower motor neuron lesions, such as ALS, the intrinsic hand muscles are often affected by atrophy.

Overview of abnormal muscle movements

• Definition: maximal effort a patient is able to exert from an individual muscle or group of muscles
• Assessment
  • The patient is asked to flex and extend the extremities against resistance.
  • Muscle power tests should be performed bilaterally for comparison.
• Muscle power grading
  • 0: no contraction (complete paralysis)
  • 1: flicker or trace of contraction
  • 2: active movement, with gravity eliminated
  • 3: active movement against gravity
  • 4: active movement against gravity and moderate resistance
  • 5: normal power (i.e., full range of motion against gravity and full resistance)
• Patterns of paresis distribution
  • Quadriparesis: weakness in all four limbs
  • Hemiparesis: weakness in half of the body
  • Paraparesis: weakness affecting both lower extremities
  • Monoparesis: paresis affecting a single limb
• Special tests
  • Pronator drift test
    • The patient is asked to raise both arms horizontally up to shoulder level, palms facing upwards, with the eyes closed (for 30 seconds).
    • The test is positive when there is asymmetric pronation and drifting movement of the arms:
      • Pronation and downwards drift indicate upper motor neuron lesion.
      • Pronation and upwards drift indicate cerebellar lesion.
  • Mingazzini test
    • The patient is asked to lie in the supine position, with eyes closed, and is asked to raise and hold both legs for 30 seconds (90° angle at knee and hip).
    • Lowering of one leg is indicative of subtle paresis.

References:^[3]

A tendon reflex is a single monosynaptic reflex (stretch). The reflex arc consists of only one synapsis connecting two neurons: an afferent sensory neuron and an efferent motor neuron.

Deep tendon reflexes (DTR)

• Definition: a reflex to test the integrity of a sensory and motor neuron circuit
• Assessment
  • During reflex testing, the patient should be relaxed.
  • Upon tapping of the reflex hammer, activation of the dorsal root ganglion causes firing of the lower motor neuron for the agonist muscle and relaxation of the antagonist muscle, resulting in automatic movement.
• Interpretation
  • An increased DTR indicates an upper motor neuron issue, whereas decreased DTR indicates an LMN, neuromuscular junction, or muscle issue.
  • Older patients may have reduced or absent lower DTR due to normal aging-related changes in muscles and tendons
  • Reinforcing maneuvers (e.g., Jendrassik maneuver) can be used to elicit a reflex that initially seems to be absent.

Use the following poem to remember which nerve roots correspond to which reflexes:
S1–S2
Buckle my shoe (ankle reflex)
L2–L4
Kick the door (knee reflex)
C5–C6
Pick up sticks (biceps reflex and brachioradialis reflex)
C7–C8
Lay them straight (triceps reflex)

Superficial reflexes

• Definition: polysynaptic reflexes elicited by stimulation of the skin
• Interpretation: superficial reflexes are considered
  • Physiological, when there is a contraction of a group of muscles after the stimulation
  • Pathological, when there is reduced or no contraction as a consequence of lower motor neuron and/or the reflex arc

Use the following poem to remember some of the superficial reflexes:
L1–L2
Testicle move (cremasteric reflex)
S3–S5
Winking by (anal wink reflex)

Primitive reflexes

• Definition: a type of reflex that is normal in newborns and infants, but not in adults
  • When present in adults, they may indicate diffuse brain injury due to a lack of common inhibiting factors.
  • See “Child development and milestones.”
• Corticospinal tract signs
  • Indicate damage to the pyramidal tract
  • Babinski sign is the most common and thus most reliable pyramidal tract sign.
  • Although these reflexes are a normal physiological response in healthy infants, they are pathological in adults.

Babinski sign, although normal in newborns and infants, is always pathological in adults.

• Definition: resistance of an individual muscle (or a group of muscles) to passive stretching
• Assessment: passive movement of the extremities
  • Upper limb
    • Elbow: The examiner flexes and fully extends the patient's elbow.
    • Forearm: With the elbow in the 90° position, the examiner supinates and pronates the patient's hand.
    • Wrist: The examiner flexes and extends and then twist the patient's wrist from side to side.
  • Lower limb: The patient is asked to relax the limbs while lying in the supine position. The examiner then rolls the legs from side to side.
• Findings ^[4][6]
  • Spasticity: characteristic of pyramidal tract lesions
    • Velocity-dependent phenomenon: Spasticity is more pronounced with increased speed of movement.
    • Clasp knife phenomenon: initial resistance due to increased muscle tone is followed by a sudden decrease in resistance
    • See “Spasticity”
  • Rigidity: suggests abnormalities of the extrapyramidal system
    • Velocity-independent phenomenon
    • Lead pipe rigidity: an increase in tone that is constant throughout the passive movement
    • Cogwheel rigidity
      • Extreme stiffness of the joint of the limb that makes movement difficult
      • When the examiner flexes or extends the limb, the movement is jerky, resembling the ratcheted rotation of a cogwheel
  • Hypotonia
    • A decrease in muscle tone
    • Can occur in peripheral nervous system lesions (e.g., polyneuropathy), lower motor neuron lesions (e.g., spinal muscular atrophy), or cerebellar lesions
  • Paratonia: a change in tone that is uneven throughout the passive movement due to involuntary opposition or facilitation by a patient
    • Occurs in patients with frontal lobe dysfunction (e.g., due to trauma, stroke, tumor, neurodegenerative disorders such as frontotemporal dementia)
    • The degree of paratonia increases with the speed of passive movement, the amount of applied force, and with attempts to relax the patient.
    • Oppositional paratonia: an apparent increase in tone due to the patient's involuntary resistance to movement
    • Facilitatory paratonia: an apparent decrease in tone due to the patient's involuntary assistance to movement
  • Clonus: a series of involuntary, rhythmic muscular contractions
    • Patellar clonus: The examiner grasps the patient's patella between the index finger and the thumb, quickly pushes it down distally, and then holds it in this position.
    • Foot clonus
      • The examiner holds the patient's leg, with both knee and ankle resting in a 90° flexion.
      • Then the examiner proceeds to dorsiflex and partially evert the foot forcefully multiple times while sustaining the pressure.
    • Wrist clonus: The examiner hyperextends the patient's wrist.
• Modified Ashworth scale: a scale that is most commonly used for assessment of the muscle tone ^[7]
  • 0: no increase in muscle tone
  • 1: slight increase in muscle tone, with minimal resistance at the end of the range of passive motion
  • 1+: slight increase in muscle tone followed by abrupt resistance (catch) that continues through the remainder (less than half) of the movement
  • 2: a marked increase in muscle tone throughout most of the range of motion, but passive movement is easy
  • 3: considerable increase in muscle tone, with passive movement difficult
  • 4: affected parts rigid in flexion or extension

Do not confuse clonus with myoclonus. Myoclonus is arrhythmical and defined by sudden jerks of a muscle or group of muscles, while clonus is rather rhythmic and defined by repetitive contractions and relaxations of a muscle group. Moreover, myoclonus is usually associated with metabolic abnormalities (e.g., renal and liver failure).

Examination of the sensory system is aimed at evaluating any abnormality affecting the patient's perception to provoked sensations like touch, pain, and temperature. In contrast to motor function, sensation is subjective to the patient and therefore the interpretation of the exam strongly depends on the patient accurately reporting what they experience.

For more information about the patterns of sensory loss in spinal cord lesions, see “Overview” in “Incomplete spinal cord syndromes.”

General considerations

• The following tests are used to test for the ability to coordinate movements, which depend on cerebellar and basal ganglia function, proprioceptive input, and muscle power.
• Limb ataxia: a lack of coordination of voluntary movements of the upper and lower extremities, is the main finding; most commonly results from lesions in the cerebellar hemispheres. ^[1]

Finger-to-nose test and finger-to-finger test

• Procedure
  • Finger-to-nose test: The patient is asked to touch the tip of their nose with the index finger
  • Finger-to-finger test: The patient is asked to alternate between touching the tip of their nose and the examiner's finger as quickly as possible with the index finger
  • The tests should be performed once with the patient's eyes open and again with the eyes closed
• Findings
  • Normally, the patient would be able to reach the target (either their nose or examiner's finger) without tremor or overshoot.
  • Patients with dysmetria are unable to touch the tip of their nose with their index finger.
  • Improvement of test results with eyes open indicates visual compensation of dysmetria, which is characteristic of sensory impairment.
  • In patients with intention tremor, the fingers will begin to shake just as they reach their nose.
  • Patients with kinetic tremor will have a tremor throughout the movement.

Heel-knee-shin test

• Procedure: The patient is asked to touch the opposite knee with a heel and slide down the shin.
• Findings
  • Normally, the patient will be able to slide the heel of one foot down the shin of the opposite leg.
  • In patients with dysmetria, the heel will deviate to alternate sides , which indicates that the patient has limb ataxia.

Rapid alternating movement test

• Procedure: The patient is asked to rapidly screw in a large imaginary light bulb using both hands.
• Findings
  • Normally, a patient is able to perform the movement.
  • Patients with dysdiadochokinesia are unable to perform rapidly alternating agonistic-antagonistic movements and thus perform the test slowly, in an uncoordinated manner.

Multiple systems are required for proper walking, such as those responsible for sensory and motor functions (including reflexes), as well as the cerebellum and the vestibular system. During the examination of the patient's gait, particular attention should be paid to body and limb posture (e.g., base of support and arm swing), steps (length, speed, and rhythm), steadiness, and turning.

Gait examination

Abnormal gait patterns

• Definition: the triad of
  • Nuchal rigidity (stiff neck): inability to flex the neck forward
  • Headache
  • Photophobia
• Examination
  • Kernig sign: In a supine patient, extension of the knee when the thigh is flexed at the hip causes pain (knee at a 90° angle).
  • Brudzinski sign: In a supine patient, passive flexion of the neck provokes involuntary lifting of both legs.
• Etiology: : due to inflammatory (bacterial/viral meningitis; ) or noninflammatory (e.g., subarachnoid hemorrhage) causes

Signs of nerve root irritation indicate an inflammatory and/or irritative process occurring at the point where the spinal nerves exit the vertebral column. Testing for signs of nerve root irritation can help determine suspected spinal root compression (e.g., by a tumor or herniated disk).

• Examination
  • Straight leg raise test (root L5–S1): In a supine patient, lifting the extended leg (< 45°) induces pain along the distribution of the lumbar roots (i.e., back pain radiating down the ipsilateral leg).
  • Crossed straight leg raise test: In a supine patient, lifting the extended leg (< 45°) induces pain in the contralateral leg with radiation into the motor/sensory area of the affected nerve root.
  • See “Diagnostics” in “Degenerative disk disease.”
• Etiology: conditions that can lead to compression of the nerve roots (e.g., degenerative disk disease, spinal tumor, spinal epidural hematoma)

Definition

Nystagmus is an involuntary, repetitive, and twitching movement of one or both eyes.

Classification

There are several types of nystagmus. The most commonly seen ones are listed below. ^[15][16]

• Jerk nystagmus: a slow movement of the eyes towards a defined direction followed by a fast, corrective movement backward (the name of the nystagmus is determined by the direction of movement in the fast phase, i.e., left-beating, right-beating, downbeat, upbeat)
  • End-gaze nystagmus
    • A physiological horizontal jerk nystagmus caused by maintenance of extreme eye position
    • In contrast, gaze-evoked nystagmus is caused by maintenance of eccentric eye positions
• Horizontal nystagmus: a type of jerk nystagmus in which the eyes move horizontally
  • Apogeotropic nystagmus
    • A variant of horizontal nystagmus in which the eyes beat toward the ceiling (or the nondependent ear) when the head is turned from side to side with the patient in supine position
    • Can be elicited using the supine roll maneuver in patients with lateral semicircular canal BPPV; and, in association with a downbeat component, in patients with cerebellar or brainstem lesions
  • Geotropic nystagmus
    • A variant of horizontal nystagmus in which the eyes beat toward the ground (or the dependent ear) when the head is turned from side to side with the patient in supine position
    • In patients with lateral semicircular canal BPPV, this type of nystagmus can be elicited using the supine-roll maneuver.
• Vertical nystagmus
  • A type of jerk nystagmus in which the eyes move vertically
  • Movement in the fast phase is either upwards or downwards (upbeat nystagmus , downbeat nystagmus )
• Torsional nystagmus: a type of jerk nystagmus with rotary oscillations of the eye along its anteroposterior axis (clockwise, counterclockwise )
  • Ipsiversive torsional nystagmus
    • A type of torsional nystagmus where the upper pole of the eye beats toward the affected side
    • Can be seen in anterior and posterior canal BPPV, as well as medial longitudinal fasciculus lesions
• Mixed nystagmus
  • A mixed pattern of different types of jerk nystagmus
  • Typically has a peripheral cause
  • Examples: vestibular neuritis (mixed horizontal-torsional), benign paroxysmal positional vertigo (mixed vertical-torsional)
• Pendular nystagmus
  • A type of nystagmus defined by sinusoidal oscillating movements of one or both eyes
  • Often related to multiple sclerosis
  • Always considered pathological

Etiology

Nystagmus can be physiological or pathological.

• Physiological nystagmus
  • Provoked by external stimuli
  • Example: caloric nystagmus, a type of horizontal jerk nystagmus caused by infusing cold or warm water into the external ear canal (See “Caloric testing” below) ^[17]
• Pathological nystagmus: can either be congenital (e.g., sensory deficiency, oculomotor abnormality) or acquired (i.e., lesions of the cerebellum, brainstem, and/or peripheral vestibular system).

Pure upbeat, pure downbeat, and pure horizontal nystagmus almost always originate from central lesions. Mixed horizontal and torsional nystagmus patterns are typical of peripheral lesions.

The nystagmus always directs towards the more activated vestibular sensory organ.

Clinical features ^[15]

• Often asymptomatic
• General symptoms
  • Blurred vision
  • Oscillopsia
  • Sensation of disequilibrium
• Peripheral nystagmus
  • Vertigo
  • Vomiting

Diagnostics

• Caloric testing ^[17]
  • A test to differentiate between peripheral and central nystagmus by infusing warm (∼ 44°C) or cold (∼ 30°C) water into the external ear canal
  • Water infusion physiologically triggers horizontal nystagmus (see vestibuloocular reflex above).
    • Warm water: towards the stimulated side (same side)
    • Cold water: away from the stimulated side (opposite side)
    • Ice-cold water: Absence of nystagmus can indicate brainstem death in comatose patients.

COWS: Cold: Opposite side; Warm: Same side (rule for the direction of nystagmus).