Apple Magic Mouse is Jerky and Unresponsive

I've been using the Apple magic mouse (Model A1296) for years and since I've updated to Mojave in November, it has gone from slow to almost unusable. The mouse pointer is jerky and unresponsive and frequently disconnects from bluetooth. Cleaning the sensor does not help, and unpairing and repairing from bluetooth occasionally fixes the problem but then it returns. Even with new batteries, the problem persists. As a work around, I've reverted to using an old wired Apple Mouse. Any suggestions? I am currently running macOS Mojave 10.14.2 on an iMac (late 2012). Thanks!