A variety of clinical tests are used to detect a subtle upper motor neuron lesion but only a few studies have measured their sensitivity and specificity. The forearm rolling test and its variant, the finger rolling test, is one such. These tests are simple and only take 5–10 s to perform. Their sensitivity has varied in different studies but in general both are more likely to be abnormal in a patient with a focal brain lesion than abnormal power, tone and reflexes. The finger rolling test is more sensitive than forearm rolling. Furthermore, an abnormal response on testing forearm and finger rolling has a high specificity for the presence of a focal brain lesion.
Statistics from Altmetric.com
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.
Clinicians use a variety of tests to detect a subtle upper motor neuron abnormality when tone, power and reflexes are normal. Which test to use is usually based on how we were taught as medical students and junior doctors, later modified by personal experience. Most neurologists adopt one or two favourites but only a few studies have measured their sensitivity and specificity for detecting a focal brain lesion, or a spinal cord lesion. Assessment for pronator drift is probably the most commonly used, and various tests of rapid alternating movements are also used. However, interpretation of rapid alternating movements can be difficult because performance in the dominant and non-dominant limb may differ in normal people.
The History of the Forearm Rolling Test
The forearm rolling test and its origin have been attributed to GH Monrad-Krohn, formerly the Professor of Neurology at the Royal Frederick University in Oslo, but he never published a description of the test. It was first described in print by Sawyer and colleagues in 1993.1
How to Do the Forearm Rolling Test
The patient is asked to clench both fists and hold both forearms horizontally with the arms partly flexed at the elbows, so that the fists and wrists overlap and are separated vertically by about 5 cm (figure 1). The patient is then instructed to rapidly rotate both forearms around each other in front of their torso for about 5 s in each direction. Normally, the fists and forearms rotate around each other symmetrically. In the presence of a unilateral upper motor neuron lesion, the contralateral forearm remains relatively stationary while the normal forearm orbits around the affected arm.
The Finger Rolling Test
Sawyer’s article prompted Yamamoto to describe a variant of the forearm rolling test.2 One of Yamamoto’s patients had commented that it was more difficult to roll his index fingers around each other than rolling his forearms. The finger rolling test is performed by the patient extending the index fingers from the clenched fists and then rotating the index fingers around each other, as in the forearm rolling test (figure 2). Finger rolling is easier to perform than the forearm rolling test if there is an intravenous line in the forearm.
Sensitivity and Specificity
The sensitivity and specificity of the forearm and finger rolling tests have been assessed in four studies.
Sawyer and colleagues studied 62 adult patients with a radiologically confirmed unilateral cerebral lesion.1 Those with a brainstem or spinal cord lesion, encephalopathy or a local disorder of the extremities that might have hindered movement were excluded. Twenty control subjects with normal imaging were also studied. The examiner was not blind to the patient’s history or the results of imaging but the forearm rolling test was assessed separately by an independent examiner with no prior knowledge of the patient. Asymmetrical forearm rolling was the most sensitive sign of a unilateral cerebral hemisphere lesion—87% (table 1). In one patient, abnormal forearm rolling was observed on the same side as the lesion.
Yamamoto compared forearm with fin- ger rolling in 28 patients with a unilateral brain lesion but no gross weakness.2 The finger rolling test was positive in 61% and forearm rolling was positive in 21%. Pronator drift was detected in 21% of these patients.
Teitelbaum and colleagues measured the sensitivity and specificity of a series of tests in 170 patients referred with a suspected abnormality in the central nervous system.3 Patients were included in the abnormal group (n=86) if CT or MRI showed a hemispheric lesion involving the motor pathways and the patients had normal strength or only mild weakness (Medical Research Council grade 4/5). If the CT or MRI were normal, the patient was included in the control group (n=84). Exclusion criteria were the presence of a spinal cord, peripheral nervous system or cerebellar lesion, sensory abnormality, abnormal movements, pain or mechanical limitation of the limbs that affected the patient’s ability to perform the manoeuvres, lack of cooperation and a history of previous central nervous system damage. They assessed power, Barré test (straight arm raising), pronator drift, fine finger movements (tapping thumb with the index finger of the same hand several times in a row), forearm rolling and deep tendon reflexes. The examiners were unaware of the patient’s diagnosis and the results of the imaging investigations. The reproducibility of the tests was assessed in 85 of the 170 patients by two independent physicians. The forearm rolling test had a sensitivity of 46% and a specificity of 98% (table 2). The sensitivity of the forearm rolling test was better than examination for segmental motor weakness but less sensitive than pronator drift, Barré test, fine finger movements and the deep tendon reflexes. The reproducibility of the forearm rolling test was 78%, which was lower than for the Barré test, pronator drift and fine finger movements.
In Auckland, we assessed a battery of motor, sensory, cranial nerve and cognitive tests in 65 adult patients who had been referred for investigation of neurological symptoms, such as headache or transient neurological events, without obvious focal signs.4 Patients with obvious focal signs, cognitive impairment, brainstem or cerebellar lesions, movement disorders, non-neurological disorders that would affect the assessment or marked midline shift on imaging were excluded. Forty-six patients had a single hemispheric lesion on brain imaging and 19 patients had no lesion. The examiner was blind to the imaging results and the patient’s history. From the results of these tests the examiner used clinical judgement to decide whether or not there was a focal lesion. The signs with the greatest sensitivities for detecting a focal lesion were abnormal finger rolling, upper motor neuron pattern of weakness, impaired rapid alternating movements (patting the thigh alternately with the dorsum or palm of the hand for 10 s), abnormal forearm rolling and pronator drift (table 3). All of these tests had a specificity of 100% (95% CIs 83% to 100%). An abnormal finger rolling test was found in 15 patients (33%), five of whom had normal power. In a few patients, however, an upper motor neuron pattern of weakness, impaired rapid alternating movements or pronator drift were detected when the finger and forearm rolling tests were normal. Overall, the neurological examination accurately identified 61% (95% CI 45% to 75%) of patients with a focal lesion while specificity was 84% (95% CI 60% to 97%).
The different sensitivities of the forearm and finger rolling tests in these studies probably can be explained by differences in the patient populations. In Auckland, only patients without obvious focal neurological signs were included4 while Teitelbaum and colleagues included patients with grade 4/5 weakness.3 Sawyer and Yamamoto did not restrict the inclusion of patients according to the presence or absence of arm weakness.1 2 Variations in technique may have explained the different sensitivities observed for the pronator drift test—for example, Teitelbaum and colleagues used explicit instructions for the performance and interpretation (they asked their patients to maintain their arms in a pronated position with the fingers adducted for 45 s and the examiner looked for abduction of the little finger and hollowing of the hand, as well as forearm pronation).3
The forearm and finger rolling tests can be abnormal when there is no increase in tone, weakness or hyperreflexia in the arm
What Can be Concluded from These Studies?
First, when patients with obvious neurological signs are excluded, the neurological examination has a low sensitivity for detection of a focal brain lesion. Secondly, the forearm and finger rolling tests can be abnormal when there is no increase in tone, weakness or hyperreflexia in the arm. Thirdly, finger rolling is more sensitive than forearm rolling.
Although the finger and forearm rolling tests are simple and only take 5–10 s to perform, they do have some drawbacks. They may be falsely lateralising with an abnormal response ipsilateral to the brain lesion. Sawyer and colleagues thought it was unlikely a patient could feign an abnormal response1 but in my experience an abnormal forearm or finger rolling test occurs quite frequently in patients with functional or psychogenic hemiparesis.
When I suspect a patient may have a focal brain lesion involving the upper motor neuron pathway, I first check tone, power, reflexes and rapid alternating movements. If these are normal, I then test pronator drift, and forearm and finger rolling.
Competing interest None.
Patient consent Obtained.