One Hand Clapping

Abstract & Commentary

By John J. Caronna, MD, Professor of Clinical Neurology, Weill Cornell Medical College. Dr. Caronna reports no financial relationships relevant to this field of study.

Synopsis: The hand clapping test is a quick and reliable way to screen for parietal lobe neglect syndrome.

Source: Ostrow LW, Llinas RH. Eastchester Clapping Sign: A novel test of parietal neglect. Ann Neurol 2009;66:114-117.

In response to a question, "what happens if you ask patients with neglect to clap their hands?" posed by an Eastchester High School student, the authors investigated how 14 patients with acute right hemisphere strokes and hemineglect responded when asked to clap their hands. The distinct phenomenology of their responses was named the Eastchester Clapping Sign (ECS). Grading of the responses was as follows: ECS-2 = one-handed clap, respects the midline; ECS-1 = searches in the contralateral hemispace for the other hand; ECS-0 = reaches over to clap against the plegic hand.

Twelve of 14 righthanded patients had an initial ECS-2 and an acute right hemisphere stroke affecting the parietal lobe on MRI. One of the remaining two patients initially was graded ECS-1 and then worsened to ECS-2 after hemorrhagic transformation of a large right hemisphere infarct. The other patient had an ECS score that was perfusion-dependent: she fluctuated between ECS-2 and ECS-0 with changes in blood pressure. Her MRI showed a right parietal perfusion deficit without infarction.

The persistence of ECS varied. Most patients went through a progression over the first few days after stroke onset. Initially they respected the midline, then started searching for the other hand over the next 24 to 48 hours.

The authors propose the ECS as a screening test for neglect in the acute stroke setting. The sign was a consistent and unambiguous finding and easily recognizable by physicians and laypersons.


Patients with right hemisphere strokes are much less likely to receive rtPA due to a failure of the patients themselves and prehospital observers to recognize the presence of neglect.1 In addition, the National Institutes of Health (NIH) stroke scale has a recognized bias toward left or dominant hemisphere strokes with language deficits. The addition of the ECS to the NIH stroke scale could increase the likelihood that patients with neglect would be recognized earlier and treated in a timely manner.

Beyond its clinical utility, the ECS should cause neurologists to meditate on the famous Zen philosophical riddle which asks, "What is the sound of one hand clapping?" Apparently, the students of Eastchester High School already have achieved a new level of enlightenment for themselves and for us.


1. Di Legge S, Fang JM, Saposnik G, et al. The impact of lesion side on acute stroke treatment. Neurology 2005; 65:81-86.