I started noticing that my Apple Wireless Mighty Mouse was stuttering (jerky). I tried a few things: turned off my wifi, rebooted, unplugged all peripherals, disabled wireless bluetooth sync with my iphone, disabled iTunes Match, prayed to the computer gods, etc..
Here’s what worked for me
Shut down iTunes.
I figured this out by simply shutting down iTunes.
Then I found the permanent solution, which had to do with a problematic file called AppleUpstreamUserClient.kext.
$ cd /System/Library/Extensions/ $ sudo mv AppleUpstreamUserClient.kext AppleUpstreamUserClient.kext.old
You may need to remove this file again if you were to upgrade the OS in the future.