Common causes of focal weakness include Stroke (the most common cause of unilateral weakness) Neuropathies, including those that are caused by trauma or entrapment (eg, carpal tunnel syndrome) and that are immune-mediated (eg, Bell palsy) Spinal root entrapment (eg, herniated intervertebral disk) Spinal cord compression (eg, cervical spondylosis, epidural cancer metastasis, trauma) Multiple sclerosis Temporary focal weakness may occur as part of postictal (Todd) paralysis, which usually resolves over several hours, or result from a transient ischemic attack (TIA) or hypoglycemia; with treatment, hypoglycemia and the resulting weakness resolve.