The abstract -- the entire abstract -- is as follows:
We studied stereotypical ear covering in a child with autism. Results of a descriptive analysis were inconclusive but revealed a correlation between ear covering and another child's screaming. An analogue functional analysis showed that ear covering was emitted only when the screaming was present.Way to avoid citing other literature, people.
The rest isn't much better. To quote the last paragraph of the paper:
These findings suggest that ear covering was maintained by negative sensory reinforcement (noise attenuation) and illustrate the importance of linking descriptive and analogue functional analyses when idiosyncratic events are implicated in behavioral maintenance. Whether a similar relation between ear covering and noise occurs for other children with autism awaits further investigation. However, the current data set implicates a previously unidentified source of reinforcement as one possible cause of stereotypical behavior.Umm... that is most certainly not a "previously unidentified source of reinforcement". Documentation on what we politely call "sensory issues" in autism goes back a biiiiit further than 2003.