Unilateral numbness of both limbs†

Cortical dysfunction (eg, stroke, tumor, multiple sclerosis, degenerative brain disorders)

Facial and body sensations lost on the side contralateral to the lesion, plus loss of cortical sensation (eg, agraphesthesia, astereognosis, extinction)

Usually nonsensory neurologic deficits (eg, weakness, hyperreflexia, ataxia)

MRI or CT

Upper brain stem or thalamus dysfunction (eg, stroke, tumor, abscess)

Facial and body sensations lost on the side contralateral to the lesion

Often cranial nerve deficits (eg, oculomotor nerve palsy on the side opposite the numbness in some upper brain stem strokes)

MRI (preferred for brain stem dysfunction) or CT

Lower brain stem dysfunction (eg, stroke, tumor, degenerative brain disorders)

Facial sensations lost on the side ipsilateral to the lesion and body sensations lost on the side contralateral to the lesion (crossed face-body distribution)

Often cranial nerve deficits

MRI

Bilateral numbness of the limbs or trunk

Transverse myelopathy‡ (eg, spinal cord compression, transverse myelitis)

Loss of sensory, motor, and reflex function below a specific spinal segment

Autonomic dysfunction (eg, bowel, bladder, and erectile dysfunction; anhidrosis)

MRI

Dorsal column spinal cord dysfunction (eg, multiple sclerosis, vitamin B12 deficiency, tabes dorsalis, HIV infection)

Disproportionate loss of vibration and position sensation

In multiple sclerosis, or other conditions that affect the posterior columns of the spinal cord (eg, B12 deficiency), numbness often described by the patient in a different way (ie, the limb feels thick or wrapped like wearing a glove or stockings)

In vitamin B12 deficiency, bilateral and symmetric findings (usually due to spinal cord dysfunction but often accompanied by a peripheral neuropathy)

MRI

Vitamin B12 level, CSF cell count and protein, CSF and blood tests for syphilis

Electromyography and nerve conduction testing (electrodiagnostic testing)

Compression of the cauda equina—also called cauda equina syndrome^† (eg, due to a herniated disk or spinal or vertebral metastases)

Numbness affecting primarily the perineum (saddle area)

Often urinary or fecal retention or incontinence, and/or loss of sphincter reflexes (eg, anal wink, bulbocavernosus)

MRI

Central cord syndrome (eg, due to trauma, tumor, or syrinx)

Numbness and weakness disproportionately affecting both upper limbs

MRI

Polyneuropathies such as

• Axonal polyneuropathies (eg, those associated with medication or toxins, diabetes, chronic kidney disease, metabolic disorders)

• Demyelinating polyneuropathies (eg, Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, toxic or drug-related demyelinating polyneuropathy)

Bilateral, roughly symmetric, mostly distal (stocking-glove distribution) paresthesias and sensory deficits

Sometimes weakness and hyporeflexia (eg, in demyelinating polyneuropathies)

Electrodiagnostic testing

Laboratory testing based on suspected disorder

Multiple mononeuropathy—also called mononeuritis multiplex (eg, associated with diabetes, systemic rheumatic diseases, infection, or metabolic disorders)

Numbness with or without pain

Usually motor and reflex deficits in the distribution of ≥ 2 peripheral nerves, sometimes affecting specific nerves sequentially (but may be clinically indistinguishable from stocking-glove distribution)

Usually electrodiagnostic testing and laboratory testing based on suspected disorder

Numbness of part of a single limb

Radiculopathy§ (eg, a herniated disk, bone compression due to osteoarthritis or rheumatoid arthritis, carcinomatous meningitis, infectious radiculopathy)

Pain (sometimes like an electric shock), sensory and often motor and/or reflex deficits in a nerve root distribution (see table Symptoms of Common Radiculopathies by Cord Level)

Pain possibly worsened by moving the spine or a Valsalva maneuver

MRI or CT

Sometimes electrodiagnostic testing

Plexopathy (eg, brachial or lumbar plexopathy, brachial neuritis, thoracic outlet compression syndrome)

Sensory deficits, pain, and motor deficits in part of a limb (sometimes most of a limb) in a distribution larger than that caused by radiculopathy or single mononeuropathy

Electrodiagnostic testing

MRI unless the cause is trauma or suspected brachial neuritis

Single mononeuropathy (eg, carpal, cubital, radial, and tarsal tunnel syndromes; ulnar, radial, and peroneal nerve palsies)

Numbness (with or without pain) and motor and reflex deficits in the distribution of a single peripheral nerve

Sometimes history and physical examination alone

Sometimes electrodiagnostic testing