Speech in Noise Discrimination Skills in Multiple Sclerosis Patients.

Air and bone conduction hearing thresholds will be measured using a Grason-Stadler GSI 61 Clinical Audiometer in a quiet room of the Industrial Acoustic Company (IAC) Inc. standard. Airway hearing thresholds will be measured using Telephonics TDH 39 headphones and bone conduction hearing thresholds will be measured using Radioear B-71 bone vibrator. Airway hearing thresholds will be evaluated at frequencies of 0.25 -8 kHz and bone conduction hearing thresholds at 0.5-4 kHz. As pure tone average, 500-1000-2000 Hz air and bone conduction thresholds will be calculated separately for both ears. A pure tone average between 0-15 dB will be considered normal hearing.

Speech Audiometry will be performed in a quiet room to IAC (Industrial Acoustic Company) standards using a Grason-Stadler GSI 61 Clinical Audiometer.

Speech reception threshold will be determined using three syllable word lists. A 40 dB Sensation Level (SL) will be added above the speech reception threshold and the patient will be asked if he/she can hear comfortably. After determining the level at which the patient can hear most comfortably, 25-word monosyllabic isophonic word lists will be read and the speech discrimination score will be calculated as a percentage. Individuals with a speech discrimination score of 88% and above and with an agreement between speech reception threshold and pure tone averages (SSO) will be included in the study.

The SDN test will be performed in a quiet room in accordance with the Industrial Acoustic Company (IAC) standard using the Grason-Stadler GSI 61 Clinical Audiometer. After pure tone audiometry and speech tests, the GKAE test will be performed. The speech in noise discrimination test will be performed with a signal-to-noise (S/N) ratio of +10 dB. A word list at 50 dB SL will be presented to the tested ear using live sound, while simultaneously white noise at 40 dB SL will be presented to the test ear (Beattie et al. 1997). This will be done for both ears. The speech in noise discrimination test scores will be calculated as percentages (%) for both ears.

TEOAE measurements of all individuals in the study and control groups will be performed using the computer-based Otodynamics ILO-V6 'cochlear emission analyzer' and software version 5.61 (Otodynamics, London). Adult TEOAE probe will be used for all OAE measurements. The probe will be calibrated in a 1 cc acoustic calibration cavity. The measurement will be performed by averaging the nonlinear, 80 µsec, 260 click stimulus response at 80 ± 3 dB SPL. "Noise rejection level of 47 dB, wave reproducibility of 70% or more, and stimulus stability greater than 80% will be taken into consideration.

For TEOAE and contralateral suppression measurements, 60 dB SL white noise will be applied from the opposite ear using a TEOAE probe and emission amplitudes will be measured from the same side ear. All OAE measurements will be performed by inserting the probe once and TEOAE and contralateral suppression tests will be performed respectively. Amplitude (dB) values obtained with suppression at 1000, 1414, 2000, 2828 and 4000 Hz will be used as study parameters.

Translated into Turkish as the Montreal Cognitive Assessment Scale and abbreviated as MOBID, MOCA assesses attention, executive/managerial functions, memory, visual-spatial skills, language, abstract thinking and arithmetic. It is easy and practical to apply. The score that can be obtained varies between 0-30. The cut-off point for cognitive impairment is 21. Patients who perform below 21 points are considered to have cognitive impairment. Although it is not a battery used in the MS patient group, a study conducted on 39 MS patients and 20 healthy people showed that it can be used safely for screening purposes in patients with MS (Aksoy et al., 2013; Nasreddine et al., 2005; Selekler & Cangoz, 2009).

Attention, visuospatial information processing speed and working memory are assessed. It is one of the subtests of the Short Repeatable Neuropsychological Battery developed to assess cognitive functions in MS (Smith, 1973).