Neurological examination and diagnostic methods

Neurological examination and diagnostic method


The neurologic examination is divided into several components and is generally done from head to toe. First assess mental status. A patient may be awake, lethargic (will follow commands and answer questions, but then returns to sleep), stuporou (difficult to arouse at all), or comatose (no purposeful response to voice or pain). Cra­nial nerves may be thoroughly tested in the awake patient, but pupil reactivity, eye movement, facial symmetry, and gag are the most relevant when mental status is impaired. Motor testing is based on maximal effort of major muscle groups in those able to follow com­mands, while assessing for amplitude and symmetry of movement to deep

central pain may be all that is possible for stuporous patients.  details scoring for motor assessment tests. Characteris­tic motor reactions to pain in patients with depressed mental status include withdrawal from stimulus, localization to stimulus, flexor (decorticate) posturing, extensor (decerebrate) posturing, or no re­action (in order of worsening pathology). diagrams the clinical patterns of posturing. This forms the basis of determining the Glasgow Coma Scale motor score, as detailed  . Light touch, proprioception, temperature, and pain testing may be useful in awake patients but is often impossible without good co­operation. It is critical to document sensory patterns in spinal cord injury patients. Muscle stretch reflexes should be checked. Often comparing left to right or upper extremity to lower extremity re­flexes for symmetry is the most useful for localizing a lesion. Check for ankle-jerk clonus or up-going toes (the Babinski test). Presence of either is pathologic and signifies upper motor neuron disease

Motor Scoring System

no muscle contraction
visible muscle contraction without movement across the joint
Movement in the horizontal plane. unable to overcome gravity
Movement against gravity

Movement against some resistance
Normal strength


Motor Response (M) Verbal Response (V) Eye-Opening Response(E

Eye opening response E
Verbal response V
Motor response M
open spontaneously 4
oriented 5
Obeys commands 6
opens to speech 3
confused 4

Localize to pain  5

opens to pain 2
inappropriate words 3
Withdraws from pain 4
no eye opening 1
unintelligible sounds 2
flexor posturing  3

no sound 1
extensor posturing 2

no movement  1

Diagnostic Studies

Plain Films

Plain x-rays of the skull may demonstrate fractures, osteolytic or osteoblastic lesions. or pneumocephaly (air in the head). The use of skull plain films has decreased given the rapid availability and significantly increased.detail of head computed tomography (CT) scans. Plain films of the cervical. thoracic. and lumbar spine are used to assess for evidence of bony trauma or soft-tissue swelling suggesting fracture. spinal deformities and osteolytic or osteoblastic
pathologic processes also will be apparent. The shoulder girdle usually poses problems in visualizing the cervicothoracic junction clearly.

Computed Tomography

The non contrast CT scan of the head is an extremely useful diag­nostic tool in the setting of new focal neurologic deficit, decreased mental status, or trauma. It is rapid and almost universally avail­able in hospitals in the United States. Its sensitivity allows for the detection of acute hemorrhage. A contrast-enhanced CT scan will help show neoplastic or infectious processes. In the current era. contrast CT is generally used for those patients who cannot undergo magnetic resonance imaging (MRl) scanning due to pacemakers or metal in the orbits. Fine-slice CT scanning of the spine is helpful for defining bony anatomy and pathology. and is usually done after an abnormality is seen on plain films. or because plain films are inadequate (especially to visualize C7 and Tl vertebrae). Finally. high-speed multislice scanners. combined with timed-bolus contrast injections. allow CT-angiography (CT-A). A thin-slice axial scan is obtained during the passage of contrast through the cerebral arteries and reconstructed in 3-D to assess for vascular lesions. CT-A does not reliably detect lesions, such as cerebral aneurysms. less than 3 mm  across. but can provide detailed morphologic data of larger lesions. Newer. multislice scanner technology is approaching the resolution of conventional angiography.

Magnetic Resonance Image

MRI provides excellent imaging of soft tissue structures in the bead and spine. It is a complex and evolving science. Several of the most clinically useful MRI sequences are worth describing. TI sequences made before and after gadolinium administration are use­ full for detecting neoplastic and infectious processes.  sequences facilitate assessment of neural compression in the spine by the pres­ence or absence of bright  CSF signals around the cord or nerve roots. Diffusion-weighted images (DWl) can detect ischemic stroke earlier than CT. Fine-slice time-of-flight (TOF) axial images can be reformatted in three dimensions to build MRI-angiograms (MR-A) and MRI-venograms (MR- V). MR-A can detect stenosis of the cer­vical carotid arteries or intracranial aneurysms greater than 3 mm in diameter. MR-V can assess the sinuses for patency or thrombosis.


Transarterial catheter-based angiography remains the gold stan­dard for evaluation of vascular pathology of the brain and spine. The current state of the art is biplanar imaging to reduce dye load and fa­cilitate interventional procedures. Digital subtraction technologies minimize bony interference in the resultant images. Bilateral carotid arteries and bilateral vertebral arteries may be injected and followed through arterial. capillary. and venous phases for a complete cerebral angiogram.

Electromyography and Nerve Conduction Studies

Electromyography and nerve conduction studies (EMG and NCS) are useful for assessing the function of peripheral nerves. EMG records muscle activity in response to a proximal stimulation of the motor nerve. NCS records the velocity and amplitude of the nerve action potential. EMG|NCS is typically performed approxi­mately 4 weeks after an acute injury, as nerves distal to the injury continue to transmit electrical impulses normally until degeneration of the distal nerve progress
Invasive Monitoring
There are several methods of monitoring intracranial physiology. The three described here are bedside intensive care unit (lCU) pro­cedures and allow continuous monitoring. All three involve making a small hole in the skull with a band-held drill. They are generally placed in the right frontal region to minimize the neurologic impact of possible complications. such as hemorrhage. The most reliable monitor, always, is an alert patient with a reliable neurologic exam. if a reliable neurologic exam is not possible due to the presence of brain injury. sedatives. or paralytics, and there is active and unstable intracranial pathology. then invasive monitoring is required

External Ventricular Drain EVD

 An EVD is also known as a ventriculostomy. A perforated plastic catheter is in­serted into the frontal horn of the lateral ventricle. An uninterrupted fluid column through a rigid tube allows transduction of intracranial pressure (lCP). CSF also can be drained to reduce ICP or sampled for laboratory studies.
Intraparenchymal Fiberoptic Pressure Transducer. This device is commonly referred to as a bolt,Again, a small hole is drilled in the skull threaded post locks securely into the skull and holds the fiberoptic catheter in place. A bolt allows ICP monitoring only, but is smaller and less invasive than a ventricu­lostomy. and may be associated with fewer complications, although the data are not clear.
Brain Tissue Oxygen Sensors. The brain tissue oxygen sensor is a recent development. The device is screwed into the skull in the same manner as the bolt; however, the sensor catheter is an electrochemical oxygen-tension sensitive membrane. A single bolt can be designed to accept a pressure sensor, oxygen sensor. and brain temperature sensor. Patients with severe brain injury due to trauma or aneurysmal haemorrahage may benefit from placement of these three sensors and a ventriculostomy to drain CSF for control of ICP. This requires two twist-drill boles, which may be adjacent or on opposite sides of the head.


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