Teorier inom Kognitiv hörselvetenskap beskriver hur uppfattning av tal beror på två olika typer av processer. Bottom-up processer associeras med akustiska och fonetiska egenskaper hos en inkommande signal och top-down processer associeras med lexikala, syntaktiska, semantiska samt kontextuella egenskaper. Förmågan att utnyttja top-down processer tros bero på kapaciteten hos arbetsminnet. För att undersöka en skillnad mellan bottom-up och top-down samt deras förhållande till arbetsminnet har ett Speech-in-Noise (SIN) test utformats och genomförts på 15 försöksdeltagare. Testet undersöker skillnader i tröskelvärden för att identifiera ett enstavigt ord i ett uppåtgående förhållande till stationärt brus, mot tröskelvärden för att identifiera ett enstavigt ord i stationärt brus med hjälp att top-down stöd. Top-down stöd ges i form av explicit priming och undersöks i både uppåtgående och nedåtgående förhållande till bruset. Två typer av arbetsminnestest, ”Letter Memory Test” och ”Reading Span Test”, användes för att undersöka en korrelation med differenser mellan tröskelvärdena. Resultaten visade på en signifikant skillnad mellan vanliga tröskelvärden och tröskelvärden då explicit top-down stöd används. Någon signifikant korrelation mellan kapaciteten hos arbetsminnet och differenserna dessa tröskelvärden fanns inte.  Dock så fann analysen en signifikant korrelation mellan skillnad i tröskelvärden, för top-down stöd i uppåtgående och nedåtgående förhållande till brus, och ”Letter Memory Test”.

Based on the former studies, there is evidence of tinnitus being associated with performance on cognitive ability tests (for example Andersson et al. 2009, Hallam et al. 2004). The topic of my bachelor thesis was to unravel how depression, stress and anxiety connected with tinnitus symptoms are related to cognitive abilities such as verbal fluency, inhibition ability and working memory capacity. In order to fill an existing gap of knowledge, the relationship of different severity of stress caused by tinnitus symptoms as measured with Tinnitus Handicap Inventory (THI) and cognitive abilities and depression and anxiety symptoms was emphasized. The experiment group was divided into two subgroups, those with lower and higher level of perceived tinnitus severity and the differences in test scores between groups were investigated with one-way analysis of variance. As a result, significant differences between the two tinnitus patient groups were found in the level of performance in inhibition task where participants were asked to give the font color of congruent color - word pair as an answer. It was also studied whether there were correlations between perceived severity of tinnitus symptoms, depression and anxiety symptoms, working memory capacity and inhibition ability. As a result of correlation analysis, this study confirmed the connection between tinnitus symptoms and anxiety and depression symptoms found in previous studies, and a significant correlation was found between THI scores and anxiety symptoms, and THI scores and C inhibition test scores where the participant was asked to name the font color from incongruent color-word pairs. The results of this study suggest that there is a connection between the level of perceived tinnitus severity and the ability to name font color of incongruent color - word pair. The current study found no evidence about the connection between THI scores and other cognitive abilities as well as anxiety and depression symptoms, even though the THI scores correlated with both anxiety symptom scores and with the reaction times of an inhibition task where the participants were asked to point out the font color from incongruent color - word pairs.

In this paper, top-down and bottom-up processing were studied regarding their effect on speech-in-noise. Three cognitive functions were also studied (divided attention, executive functioning, and semantic comprehension), and the effect they have on the speech processing and on each other. The research questions asked were if a difference in speech-in noise perception can be observed regarding the different levels of top-down and bottom-up support, if speech-in-noise is related to any of the researched cognitive abilities, and if there exists any correlation between these abilities. The method is a within-subject experimental design, consisting of four different tests: PASAT, to measure attention, LIT, to measure semantic comprehension, TMT, to measure executive functioning and SIN, to measure speech-in noise. The results showed a significant difference between top-down and bottom-up processing, a significant difference between top-down processing in decreasing and increasing conditions could also be seen. A negative correlation between the benefit of top-down support and the semantic comprehension task was found. Regarding the cognitive abilities a few correlations were found; the semantic comprehension task had a positive correlation to both the central executive task and the attentional task, the attentional task had a negative correlation to the central executive task, and both of the central executive subtasks had a positive correlation to each other. Most of the findings were expected, built on earlier cognitive hearing theories and studies.

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