Tinnitus masker issues associated with use of tinnitus maskers: the "safe" level of continuous sound depends on the duration of the sound. For maskers worn continuously, or most of the day, a safe level is no more than 70db, in accordance with EPA maximum safe exposure level for 24-hour environmental sound. Maskers louder than 45db or so (the ambient background level of an average home living area) may start to interfere with understanding conversation (about 60db). Masking of high frequency tinnitus (>6,000hz) is difficult because of the resonance characteristics of the human ear as well as high frequency limitations of in-ear devices.
Body part as an object 1963 article, and the results replicated by Overton & Jackson. Their findings suggest younger children were more likely to use BPO pantomimes to create a tangible representation of the object they were pantomiming. Boyatzis & Watson suggests that the decrease in BPO pantomime usage with age is a result of developing symbolic maturity, as older children can use a less concrete representational form. Body part as object errors are defined as the use of BPO pantomimes in place of the IO pantomimes dominant in typical adult individuals. It has been debated whether the existence of BPO errors can be used