Contextual effects on loudness judgments for sounds with continuous changes of intensity are reflected in nonauditory areas.

Psychoacoustic research suggests that judgments of perceived loudness change differ significantly between sounds with continuous increases and decreases of acoustic intensity, often referred to as "up-ramps" and "down-ramps." The magnitude and direction of this difference, in turn, appears to depend on focused attention and the specific task performed by the listeners. This has led to the suspicion that cognitive processes play an important role in the development of the observed context effects.

Deductive development and validation of a questionnaire to assess sensitivity to very low and very high frequency sounds: SISUS-Q (Sensitivity to Infra-Sound and Ultra-Sound Questionnaire).

Objective: Auditory research and complaints about environmental noise indicate that there exists a significant, small subgroup within the population which is sensitive towards infra- and low-frequency or ultra- and high-frequency sounds (ILF/UHF). This paper reports on the development, factorization and validation of measures of sensitivity towards frequencies outside the common hearing range.

Design: A multinational, cross-sectional survey study was run.

Activation in human auditory cortex in relation to the loudness and unpleasantness of low-frequency and infrasound stimuli.

Low frequency noise (LFS) and infrasound (IS) are controversially discussed as potential causes of annoyance and distress experienced by many people. However, the perception mechanisms for IS in the human auditory system are not completely understood yet. In the present study, sinusoids at 32 Hz (at the lower limit of melodic pitch for tonal stimulation), as well as 8 Hz (IS range) were presented to a group of 20 normal hearing subjects, using monaural stimulation via a loudspeaker sound source coupled to the ear canal by a long silicone rubber tube.

Exploring Differences in Speech Processing Among Older Hearing-Impaired Listeners With or Without Hearing Aid Experience: Eye-Tracking and fMRI Measurements.

Recently, evidence has been accumulating that untreated hearing loss can lead to neurophysiological changes that affect speech processing abilities in noise. To shed more light on how aiding may impact these effects, this study explored the influence of hearing aid (HA) experience on the cognitive processes underlying speech comprehension. Eye-tracking and functional magnetic resonance imaging (fMRI) measurements were carried out with acoustic sentence-in-noise (SiN) stimuli complemented by pairs of pictures that either correctly (target picture) or incorrectly (competitor picture) depicted the sentence meanings.

The representation of level and loudness in the central auditory system for unilateral stimulation.

Loudness is the perceptual correlate of the physical intensity of a sound. However, loudness judgments depend on a variety of other variables and can vary considerably between individual listeners. While functional magnetic resonance imaging (fMRI) has been extensively used to characterize the neural representation of physical sound intensity in the human auditory system, only few studies have also investigated brain activity in relation to individual loudness.

Auditory fMRI of Sound Intensity and Loudness for Unilateral Stimulation.

We report a systematic exploration of the interrelation of sound intensity, ear of entry, individual loudness judgments, and brain activity across hemispheres, using auditory functional magnetic resonance imaging (fMRI). The stimuli employed were 4 kHz-bandpass filtered noise stimuli, presented monaurally to each ear at levels from 37 to 97 dB SPL. One diotic condition and a silence condition were included as control conditions.

Modulation of nicotine effects on selective attention by DRD2 and CHRNA4 gene polymorphisms.

Rationale: Pharmacological and genetic modulation of cholinergic nicotinic neurotransmission influence visuospatial attention in humans. Prior studies show that nicotine as well as a single nucleotide polymorphism (SNP) in the gene coding for the alpha 4 subunit of the nicotinic acetylcholine receptor (CHRNA4) modulate visuospatial attention and distractor interference. The CHRNA4 gene synergistically interacts with a polymorphism in the dopaminergic receptor type d2 (DRD2) gene and impacts brain structure and cognition.

Nicotine reduces distraction under low perceptual load.

Rationale: Several studies provide evidence that nicotine alleviates the detrimental effects of distracting sensory stimuli. It is been suggested that nicotine may either act as a stimulus filter that prevents irrelevant stimuli entering awareness or by enhancing the attentional focus to relevant stimuli via a boost in processing capacity.

Objectives: To differentiate between these two accounts, we administered nicotine to healthy non-smokers and investigated distractor interference in a visual search task with low and high perceptual load to tax processing capacity.