A new computer mouse adapter is making it easier for people with essential tremor or other tremor conditions such as Parkinson's disease to open an e-mail and navigate a Web site.

The adapter, invented by IBM researchers to filter out involuntary hand tremors, is plugged in between the computer and the mouse and can be switched on or off and adjusted, depending on the tremor severity. It can also be set to filter out unintended multiple clicking on the mouse caused by a shaking finger.

The Assistive Mouse Adapter can be purchased for about $120 through British company Montrose Secam's website: http://www.montrosesecam.com/index1.html.