IHS ILE Exam Questions & Answers!

What does decreasing the compression ratio do, and when would you use this? - ANSWER Soft sound amplification is unaltered, but gain is increased for moderate/loud sounds. Most often used if a PT complains loud sounds aren't loud enough or sound "mushy" What does increasing the compression ratio do, and when would you use this? - ANSWER Soft sound gain is unaltered, but gain for moderate/loud sounds is lowered. Most often used if a PT complains loud/moderate sounds are too loud or background noise is too loud. ** sometimes you use this on just certain frequencies, for example, high frequencies if they complain dishes are too loud, or low frequencies if they complain their voice is echo-y What happens when you raise a knee point, and when would you do this? - ANSWER You will decrease gain for soft sounds and raise gain for moderate/loud sounds. Most often used if they hear soft sounds better than moderate ones ( like hearing the table across from them better than their own in a restaurant) or when they complain about hearing a HA's circuit noise. What does lowering the kneepoint do, and when would you do this? - ANSWER Lowering the KP will lower gain for moderate and loud sounds, and increase gain for soft sounds below the original KP. Mostly used when a PT complains they can't hear soft sounds like soft voices, bird chirping, or ticking clocks. What are the two types of compression? - ANSWER Input compression - when the input level of a HA determines when compression is activated. Output compression - when the output (input + gain) of the HA determines when compression is activated. What is Wide Dynamic Range Compression? - ANSWER (WDRC) This is what most HA's utilize today, and allows the signal to be packaged withing a user's DR. Typically WDRC HA's have low (35-55 dB SPL) KPs and low (1:1 - 1:4) ratios What is the Compression Ratio? - ANSWER The ratio of change between the input and output of a HA. This determines how much compression will occur. What is the Kneepoint? (KP) - ANSWER The lowest level at which compression is applied What is Harmonic Distortion? - ANSWER Harmonic distortion occurs when a single frequency is presented to the input of a hearing aid and the output contains the original frequency plus additional undesired frequencies that are harmonically related to the original frequency. ANSI uses a harmonic distortion test that measures the distortion rate at specific Hz. Frequency Response Curve - ANSWER Used in ANSI testing. A gain curve is run with the input sound at 60 dB SPL to simulate conversation level. You get the frequency range calculation from this test.