Ear we go

Kathleen Manning (Letters, 19 March) observes that my ear- blocking experiment suffers interference from throbbing, probably due to the proximity of the carotid artery. The slightest vibration of your finger will also be heard as a deep rumble; press your knuckles against the cheekbone, and try to focus attention on your free ear.
By The Newsroom
Published 22nd Mar 2010, 20:19 BST
Updated 22nd Mar 2010, 20:26 BST

The aim is to experience perception without the main mechanism by which we discriminate sound direction, which is important for focusing attention; without it, sounds can become a confusing babble. Deterioration of the brain's ability to decode direction is likely to contribute to poor hearing in the elderly.

CHILTON R INGLIS

Wilton Street

Glasgow