Coordination is evaluated by testing the patient’s ability to perform rapidly alternating and point-to-point movements correctly.
Rapidly Alternating Movement Evaluation
Ask the patient to place their hands on their thighs and then rapidly turn their hands over and lift them off their thighs. Once the patient understands this movement, tell them to repeat it rapidly for 10 seconds. Normally this is possible without difficulty. This is considered a rapidly alternating movement.
Dysdiadochokinesis is the clinical term for an inability to perform rapidly alternating movements. Dysdiadochokinesia is usually caused by multiple sclerosis in adults and cerebellar tumors in children. Note that patients with other movement disorders (e.g. Parkinson’s disease) may have abnormal rapid alternating movement testing secondary to akinesia or rigidity, thus creating a false impression of dysdiadochokinesia.
Point-to-Point Movement Evaluation
Finger to Finger
Next, ask the patient to extend their index finger and touch their nose, and then touch the examiner’s outstretched finger with the same finger. Ask the patient to go back and forth between touching their nose and examiner’s finger. Once this is done correctly a few times at a moderate cadence, ask the patient to continue with their eyes closed. Normally this movement remains accurate when the eyes are closed. Repeat and compare to the other hand.
Dysmetria is the clinical term for the inability to perform point-to-point movements due to over or under projecting ones fingers.
Next have the patient perform the heel to shin coordination test. With the patient lying supine, instruct him or her to place their right heel on their left shin just below the knee and then slide it down their shin to the top of their foot. Have them repeat this motion as quickly as possible without making mistakes. Have the patient repeat this movement with the other foot. An inability to perform this motion in a relatively rapid cadence is abnormal.
The heel to shin test is a measure of coordination and may be abnormal if there is loss of motor strength, proprioception or a cerebellar lesion. If motor and sensory systems are intact, an abnormal, asymmetric heel to shin test is highly suggestive of an ipsilateral cerebellar lesion.
The Dix-Hallpike test is performed with the patient sitting upright with the legs extended. The patient’s head is then rotated by approximately 45 degrees. The clinician helps the patient to lie down backwards quickly with the head held in approximately 20 degrees of extension. This extension may either be achieved by having the clinician supporting the head as it hangs off the table or by placing a pillow under their upper back. The patient’s eyes are then observed for about 45 seconds as there is a characteristic 5-10 second period of latency prior to the onset of nystagmus. If rotational nystagmus occurs then the test is considered positive for benign positional vertigo. During a positive test, the fast phase of the rotatory nystagmus is toward the affected ear, which is the ear closest to the ground. The direction of the fast phase is defined by the rotation of the top of the eye, either clockwise or counter-clockwise. Home devices are available to assist in the performance of the Dix-Hallpike Maneuver for patients with a diagnosis of BPPV.
There are several key characteristics of a positive test:
Latency of onset (usually 5-10 seconds)
Torsional (rotational) nystagmus. If no torsional nystagmus occurs but there is upbeating or downbeating nystagmus, a central nervous system (CNS) dysfunction is indicated.
Upbeating or downbeating nystagmus. Upbeating nystagmus indicates that the vertigo is present in the posterior semicircular canal of the tested side. Downbeating nystagmus indicates that the vertigo is in the anterior semicircular canal of the tested side.
Fatigable nystagmus. Multiple repetition of the test will result in less and less nystagmus.
Reversal. Upon sitting after a positive maneuver the direction of nystagmus should reverse for a brief period of time.
To complete the test, the patient is brought back to the seated position, and the eyes are examined again to see if reversal occurs. The nystagmus may come in paroxysms and may be delayed by several seconds after the maneuver is performed.
If the test is negative, it makes benign positional vertigo a less likely diagnosis and CNS involvement should be considered.
Pendular reflexes are not brisk but involve less damping of the limb movement than is usually observed when a deep tendon reflex is elicited. Patients with cerebellar injury may have a knee jerk that swings forwards and backwards several times. A normal or brisk knee jerk would have little more than one swing forward and one back. Pendular reflexes are best observed when the patient’s lower legs are allowed to hang and swing freelly off the end of an examining table.
Gait is evaluated by having the patient walk across the room under observation. Gross gait abnormalities should be noted. Next ask the patient to walk heel to toe across the room, then on their toes only, and finally on their heels only. Normally, these maneuvers possible without too much difficulty.
Be certain to note the amount of arm swinging because a slight decrease in arm swinging is a highly sensitive indicator of upper extremity weakness.
Also, hopping in place on each foot should be performed.
Walking on heels is the most sensitive way to test for foot dorsiflexion weakness, while walking on toes is the best way to test early foot plantar flexion weakness.
Abnormalities in heel to toe walking (tandem gait) may be due to ethanol intoxication, weakness, poor position sense, vertigo and leg tremors. These causes must be excluded before the unbalance can be attributed to a cerebellar lesion. Most elderly patients have difficulty with tandem gait purportedly due to general neuronal loss impairing a combination of position sense, strength and coordination. Heel to toe walking is highly useful in testing for ethanol inebriation and is often used by police officers in examining potential “drunk drivers”.
Tandem gait is a gait (method of walking or running) where the toes of the back foot touch the heel of the front foot at each step. Neurologists sometimes ask patients to walk in a straight line using tandem gait as a test to help diagnose ataxia, especially truncal ataxia, because sufferers of these disorders will have an unsteady gait. However, the results are not definitive, because many disorders or problems can cause unsteady gait (such as vision difficulties and problems with the motor neurons or associative cortex). Therefore, inability to walk correctly in tandem gait does not prove the presence of ataxia.
The “stepping test” was first developed by Fukuda as a test of vestibular function. More recently, the test has been shown to greater reflect somatosensory function
The test is performed by having the patient stand with eyes closed, arms outstretched and wearing ear muffs. The patient marches in place at the pace of a brisk walk while keeping the eyes closed. The doctor observes for any rotation that takes place. Rotation of 30 degrees or more is considered a positive test. The significance of the test is that it suggests the presence of either faulty kinesthetic sense or tonic neck reflexes (or both). In the low back pain patient, a positive test is likely a reflection of either faulty kinesthetic sense or faulty tonic lumbar reflexes.
Next, perform the Romberg test by having the patient stand still with their heels together. Ask the patient to remain still and close their eyes. If the patient loses their balance, the test is positive.
To achieve balance, a person requires 2 out of the following 3 inputs to the cortex: 1. visual confirmation of position, 2. non-visual confirmation of position (including proprioceptive and vestibular input), and 3. a normally functioning cerebellum. Therefore, if a patient loses their balance after standing still with their eyes closed, and is able to maintain balance with their eyes open, then this is indicative of pathology in the proprioceptive pathway. This is a positive Romberg.
To conclude the gait exam, observe the patient rising from the sitting position. Note gross abnormalities.