The nervous system consists of the brain, spinal cord, and nerves that connect the brain and spinal cord to the rest of the body (peripheral nerves Overview of the Peripheral Nervous System The peripheral nervous system refers to the parts of the nervous system that are outside the central nervous system, that is, those outside the brain and spinal cord. Thus, the peripheral nervous... read more ).
Doctors may suspect a problem with the brain, spinal cord, or nerves based on symptoms. Symptoms resulting from a disorder that affects part or all of the nervous system (a neurologic disorder) are called neurologic symptoms.
Because the nervous system controls so many different body functions, neurologic symptoms can vary greatly. They can include the following:
Abnormal sensations in the skin
Problems with vision, taste, smell, and hearing.
All forms of pain Overview of Pain Pain is an unpleasant sensation signaling actual or possible injury. Pain is the most common reason people seek medical care. Pain may be sharp or dull, intermittent or constant, or throbbing... read more (including headache Overview of Headache A headache is pain in any part of the head, including the scalp, upper neck, face, and interior of the head. Headaches are one of the most common reasons people visit a doctor. Headaches interfere... read more and back pain Low Back Pain Low back pain and neck pain are among the most common reasons for health care visits. The pain usually results from problems with the musculoskeletal system—most notably the spine, including... read more
)
Neurologic symptoms may be minor (such as a foot that has fallen asleep) or life threatening (such as coma due to stroke).
The characteristics and pattern of symptoms help doctors diagnose the neurologic disorder.
When people have symptoms that suggest a neurologic disorder, doctors ask specific questions about the symptoms and other relevant factors (the medical history Medical History in Neurologic Disorders Before doing a physical examination, doctors interview the person to obtain information about the person's current and past health (medical history). The history is the most important part of... read more ). Doctors usually also do a physical examination to evaluate all of the body systems, but they focus on the nervous system (called the neurologic examination Neurologic Examination When a neurologic disorder is suspected, doctors usually evaluate all of the body systems during the physical examination, but they focus on the different parts of the nervous system. Examination... read more ).
The neurologic examination helps doctors do the following:
Identify the location of the abnormality that is causing the symptoms
Determine whether the problem originates in the nervous system or elsewhere in the body but affects the nervous system (such as an infection, cancer, or an injury)
Determine whether tests are needed and, if needed, which tests should be done
Diagnostic tests Tests for Brain, Spinal Cord, and Nerve Disorders Diagnostic procedures may be needed to confirm a diagnosis suggested by the medical history and neurologic examination. Imaging tests commonly used to diagnose nervous system (neurologic) disorders... read more 
may be needed to confirm a diagnosis or exclude other possible disorders.
