Residency · Residency · Neurology
The Neurological Examination: A Systematic Approach
Overview
The neurological examination is the cornerstone of clinical neurology, serving as the primary tool for localization before any imaging or laboratory testing is obtained. A structured, reproducible approach ensures completeness and efficient documentation. Importantly, the examination must always be tailored to the clinical context -- a focused stroke assessment in the emergency department looks very different from a comprehensive outpatient evaluation, though both follow the same underlying principles.
Mental Status Examination
Level of Consciousness
Assessing the level of consciousness is the first step in any neurological evaluation. The Glasgow Coma Scale (GCS) quantifies consciousness across three domains -- eye opening, verbal response, and motor response -- yielding a score from 3 to 15. In intubated patients, the FOUR Score is superior to the GCS because it replaces the verbal component with assessments of brainstem reflexes and respiratory patterns, providing a range of 0 to 16. Clinicians also use descriptive terms: alert (fully awake and responsive), lethargic (drowsy but arousable), obtunded (difficult to arouse and confused when awake), stuporous (arousable only with vigorous stimulation), and comatose (unarousable).
| GCS Component | Response | Score |
|---|---|---|
| Eye Opening | Spontaneous | 4 |
| To voice | 3 | |
| To pain | 2 | |
| None | 1 | |
| Verbal Response | Oriented | 5 |
| Confused | 4 | |
| Inappropriate words | 3 | |
| Incomprehensible sounds | 2 | |
| None | 1 | |
| Motor Response | Obeys commands | 6 |
| Localizes pain | 5 | |
| Withdraws (flexion) | 4 | |
| Abnormal flexion (decorticate) | 3 | |
| Extension (decerebrate) | 2 | |
| None | 1 |
Orientation and Attention
Orientation is tested across four domains: person, place, time, and situation. Attention, which reflects the integrity of diffuse cortical networks, can be assessed with digit span (a normal forward span is at least 5, backward at least 3), serial 7s, spelling "WORLD" backward, or reciting the months of the year in reverse. Inattention is a hallmark of diffuse cortical dysfunction or delirium and should not be confused with focal deficits.
Language
Language assessment encompasses several dimensions. Fluency is evaluated by observing spontaneous speech output, phrase length, and the presence of paraphasic errors. Comprehension is tested with single-step and multi-step commands. Repetition is assessed with phrases like "No ifs, ands, or buts." Naming should include both high-frequency objects (such as a watch or pen) and low-frequency items (like the stem of a watch or clip of a pen). Reading and writing should also be tested as part of a thorough language evaluation.
Memory
Memory testing begins with registration and immediate recall of three words, followed by delayed recall at five minutes. If the patient cannot freely recall the words, recognition testing (offering multiple choices) helps distinguish whether the problem lies in encoding (a hippocampal issue, where recognition also fails) or retrieval (a frontal or subcortical issue, where recognition succeeds).
Higher Cortical Function
Visuospatial function is tested with clock drawing, intersecting pentagons, and line bisection. Executive function is assessed through Luria hand sequences, go/no-go tasks, and the Trail Making Test. Praxis is evaluated by asking patients to pantomime actions like brushing teeth or combing hair, distinguishing between ideomotor apraxia (impaired pantomime but improved with actual object use) and ideational apraxia (impaired even with objects). Neglect testing includes double simultaneous stimulation, line bisection, and cancellation tasks.
Cranial Nerve Examination
CN I (Olfactory)
The olfactory nerve is tested using non-irritating substances such as coffee or vanilla. This is often omitted in routine examinations unless frontal lobe pathology or anosmia is specifically suspected.
CN II (Optic)
Visual acuity is measured with a Snellen chart or near card. Visual fields are assessed by confrontation using finger counting or red pin comparison. Fundoscopy evaluates for papilledema, optic pallor, and the presence or absence of spontaneous venous pulsations. The swinging flashlight test detects an afferent pupillary defect (Marcus Gunn pupil), which indicates asymmetric optic nerve dysfunction.
CN III, IV, VI (Oculomotor, Trochlear, Abducens)
Pupil size, shape, and reactivity (both direct and consensual responses) are documented first. Extraocular movements are tested in all cardinal directions of gaze. Nystagmus is characterized by its direction, the fast phase, and whether it is gaze-evoked or spontaneous. Ptosis is assessed for levator function, fatigability (suggesting myasthenia gravis), and response to the ice test.
CN V (Trigeminal)
Facial sensation is tested in the V1, V2, and V3 distributions using light touch, pinprick, and temperature. Motor function of the trigeminal nerve is evaluated through masseter and temporalis strength during jaw opening, noting that the jaw deviates toward the weak side. The corneal reflex has its afferent limb through V1 and its efferent limb through CN VII. A brisk jaw jerk reflex is an upper motor neuron sign localizing above the mid-pons.
CN VII (Facial)
The key distinction in facial weakness is whether the upper face is spared. Forehead sparing indicates an upper motor neuron pattern, while complete facial weakness (including the forehead) points to a lower motor neuron lesion. Facial strength is graded by testing eye closure, nasolabial fold depth, and smile symmetry. Taste on the anterior two-thirds of the tongue, mediated by CN VII, is tested with sugar or salt solutions when relevant.
CN VIII (Vestibulocochlear)
Hearing is screened with finger rub and further evaluated with the Weber test (which lateralizes to one ear) and the Rinne test (normally, air conduction exceeds bone conduction). Vestibular function is assessed with the head impulse test, Dix-Hallpike maneuver, and nystagmus evaluation.
CN IX, X (Glossopharyngeal, Vagus)
Palate elevation is observed during phonation; the uvula deviates away from the weak side. The gag reflex has its afferent arc through CN IX and efferent arc through CN X. Voice quality should be assessed, as hoarseness suggests vagal dysfunction.
CN XI (Spinal Accessory)
The sternocleidomastoid is tested by having the patient turn their head against resistance. This tests the ipsilateral SCM but is controlled by the contralateral cortex. The trapezius is tested by shoulder shrug against resistance.
CN XII (Hypoglossal)
On tongue protrusion, the tongue deviates toward the weak side in lower motor neuron lesions. Tongue atrophy and fasciculations are additional lower motor neuron signs.
Motor Examination
Inspection
The motor examination begins with careful inspection for muscle atrophy, fasciculations, abnormal postures, and involuntary movements. Pronator drift testing, performed with the arms outstretched, palms up, and eyes closed, is one of the most sensitive screens for subtle upper motor neuron weakness.
Tone
Tone abnormalities fall into distinct patterns. Spasticity is velocity-dependent with a clasp-knife quality and reflects upper motor neuron pathology. Rigidity, which can be lead-pipe or cogwheel in character, is an extrapyramidal sign. Hypotonia may result from lower motor neuron disease, cerebellar dysfunction, or acute upper motor neuron injury during the spinal shock phase.
Strength Testing
Muscle strength is graded on the Medical Research Council (MRC) scale from 0 (no contraction) to 5 (normal strength against full resistance). Testing should include both proximal and distal muscles in all four extremities. Key myotomes to assess include C5 (deltoid), C6 (wrist extensors), C7 (triceps), C8 (finger flexors), T1 (finger abductors), L2 (hip flexors), L3 (knee extensors), L4 (ankle dorsiflexors), L5 (great toe extensors), and S1 (ankle plantarflexors).
| MRC Grade | Description |
|---|---|
| 0 | No contraction |
| 1 | Flicker or trace contraction |
| 2 | Active movement with gravity eliminated |
| 3 | Active movement against gravity |
| 4 | Active movement against gravity and resistance |
| 5 | Normal power |
| Root Level | Muscle | Test Movement | |
|---|---|---|---|
| C5 | Deltoid | Shoulder abduction | |
| C6 | Wrist extensors | Wrist extension | |
| C7 | Triceps | Elbow extension | |
| C8 | Finger flexors | Finger flexion | |
| T1 | Finger abductors | Finger abduction | |
| L2 | Iliopsoas | Hip flexion | |
| L3 | Quadriceps | Knee extension | |
| L4 | Tibialis anterior | Ankle dorsiflexion | |
| L5 | Extensor hallucis longus | Great toe extension | |
| S1 | Gastrocnemius | Ankle plantarflexion | In upper motor neuron weakness, the extensors tend to be weaker in the upper limbs and the flexors weaker in the lower limbs. Lower motor neuron weakness follows a specific nerve or root distribution. |
Reflexes
Deep tendon reflexes are graded from 0 (absent) through 2+ (normal) to 4+ (clonus). The key reflexes and their root levels are biceps (C5-6), brachioradialis (C5-6), triceps (C7), patellar (L3-4), and Achilles (S1).
| Reflex | Root Level |
|---|---|
| Biceps | C5-6 |
| Brachioradialis | C5-6 |
| Triceps | C7 |
| Patellar | L3-4 |
| Achilles | S1 |
| Grade | Interpretation | |
|---|---|---|
| 0 | Absent | |
| 1+ | Diminished | |
| 2+ | Normal | |
| 3+ | Brisk (may be normal) | |
| 4+ | Clonus | Pathological reflexes such as the Babinski sign (indicating upper motor neuron dysfunction) and the Hoffman sign are important to elicit. Primitive reflexes -- including grasp, snout, and palmomental reflexes -- are frontal lobe release signs. If reflexes appear absent, the Jendrassik maneuver (reinforcement) should be attempted; absent reflexes despite reinforcement confirm true areflexia. |
Sensory Examination
Primary Modalities
Light touch is tested with a cotton wisp. Pinprick discrimination (sharp versus dull) assesses the spinothalamic pathway. Temperature sensation can be tested with a cold tuning fork or cool object. Vibration is assessed with a 128 Hz tuning fork placed on distal joints first (great toe, then finger). Proprioception is evaluated by testing joint position sense at the distal interphalangeal joints.
Cortical Sensory Modalities
Cortical sensory testing goes beyond primary modalities. Stereognosis involves identifying objects by touch alone. Graphesthesia tests the ability to recognize numbers traced on the palm. Two-point discrimination and double simultaneous stimulation round out the cortical sensory examination. Extinction on double simultaneous stimulation (perceiving only one of two simultaneous stimuli) indicates a parietal lesion.
Sensory Patterns
Recognizing sensory patterns is critical for localization. A stocking-glove distribution points to peripheral neuropathy. A dermatomal pattern suggests radiculopathy. A sensory level on the trunk is pathognomonic for a spinal cord lesion. A hemisensory deficit implicates the thalamus or cortex. Dissociated sensory loss, where some modalities are affected but others are spared, suggests a central cord or brainstem lesion.
Coordination and Cerebellar Examination
Cerebellar function is evaluated through several maneuvers. The finger-to-nose test reveals dysmetria (past-pointing) and intention tremor. The heel-to-shin test assesses limb ataxia. Rapid alternating movements detect dysdiadochokinesia. The rebound check (Holmes' rebound phenomenon) tests the ability to arrest a movement rapidly. Truncal ataxia, manifested as difficulty sitting unsupported, points to a midline cerebellar lesion.
Gait Assessment
Gait assessment is among the most informative parts of the neurological examination. The casual gait is observed for cadence, stride length, arm swing, and base of support. Tandem gait (heel-to-toe walking) is a sensitive test for subtle ataxia. Heel walking tests L5 strength, and toe walking tests S1 strength. The Romberg test, in which the patient stands with feet together and eyes closed, is positive when balance worsens with eye closure, indicating proprioceptive or vestibular dysfunction -- not cerebellar dysfunction, since cerebellar patients are unsteady even with their eyes open. Classic gait patterns include spastic gait (circumduction), steppage gait (foot drop), waddling gait (proximal weakness), ataxic gait (wide-based), and Parkinsonian gait (shuffling with reduced arm swing and festination).
Documentation and Screening Examinations
NIH Stroke Scale (NIHSS)
The NIHSS is a standardized 11-item assessment tool for grading acute stroke severity. It evaluates consciousness, gaze, visual fields, facial palsy, motor function in the arms and legs, limb ataxia, sensory function, language, dysarthria, and extinction or inattention. It can be administered rapidly at the bedside and is critical for determining thrombolysis eligibility and establishing prognosis.
Abbreviated Screening Examination
When time is limited, such as in the emergency department, a focused screening examination should at minimum include mental status, key cranial nerves (pupils, extraocular movements, facial symmetry), pronator drift, finger-to-nose coordination, and gait assessment. The fundoscopic examination should never be skipped in patients presenting with headache, possible papilledema, or altered mental status.
<image>A detailed medical illustration showing the systematic neurological examination sequence performed on a patient seated on an exam table. The illustration is divided into panels: (1) mental status testing with examiner showing visual cards, (2) cranial nerve exam with penlight and ophthalmoscope, (3) motor exam showing pronator drift testing, (4) sensory exam with tuning fork on great toe, (5) coordination testing with finger-to-nose, and (6) gait assessment showing tandem walking. Each panel is labeled with the examination component.</image>
<image>An annotated diagram of the MRC muscle strength grading scale from 0 to 5, with each grade illustrated by a clinical drawing showing the patient-examiner interaction. Grade 0 shows no visible contraction, Grade 3 shows movement against gravity only, and Grade 5 shows normal power against full resistance. A sidebar table lists key myotomes with their spinal root levels and test movements.</image>
<image>A medical illustration depicting deep tendon reflex arc anatomy, showing the afferent sensory neuron from the muscle spindle, the synapse in the spinal cord, and the efferent motor neuron to the muscle. Inset panels show the technique for eliciting biceps (C5-6), patellar (L3-4), and Achilles (S1) reflexes with proper hammer placement. A separate panel shows the Babinski response with fanning of toes and dorsiflexion of the great toe.</image>
Clinical Pearls
Asymmetry is often more informative than absolute findings, so always compare sides during the examination. Pronator drift is one of the most sensitive tests for subtle upper motor neuron weakness and should never be omitted. A positive Romberg test indicates a sensory problem (proprioceptive or vestibular), not a cerebellar problem, since cerebellar patients are unsteady with their eyes open. The pattern of weakness matters more than severity: an upper motor neuron (pyramidal) distribution versus a lower motor neuron (specific nerve or root) distribution is what guides localization. Forehead sparing in facial weakness indicates an upper motor neuron lesion from the contralateral cortex or subcortical white matter, whereas complete facial weakness including the forehead points to a lower motor neuron CN VII lesion. The NIHSS score should be documented for every stroke patient given its prognostic and therapeutic implications. Fasciculations alone do not diagnose ALS -- they must be accompanied by other lower motor neuron signs (weakness, atrophy) and upper motor neuron signs. Finally, the neurological examination truly begins the moment the patient walks into the room: gait, posture, facial expression, and spontaneous speech all provide valuable information before formal testing even starts.
References
- Campbell WW. DeJong's The Neurological Examination. 8th ed. Lippincott Williams & Wilkins; 2020.
- Biller J, Gruener G, Brazis PW. DeMyer's The Neurologic Examination: A Programmed Text. 7th ed. McGraw-Hill; 2017.
- Blumenfeld H. Neuroanatomy Through Clinical Cases. 3rd ed. Sinauer Associates; 2021.
- Goldberg S. The Four-Minute Neurologic Exam. MedMaster; 2017.
