Loudness Judgments Research Articles

Some factors affecting loudness measurement and prediction

The current ANSI standard (ANSI S3.4, 2007) estimates the loudness of sustained sound, but many naturally occurring sounds have time-varying levels. Glasberg and Moore (2002) published a model for the prediction of time-varying sounds and this aspect should be considered as part of a revision to the ANSI standard. To assess the predictions of the dynamic model, loudness magnitude estimation functions were obtained for 24 listeners using pure tones (0.5 and 1.0 kHz), vowels, spondees, and speech-shaped noise (SSN) presented at levels from 40 to 90 dB SPL. Inferred equal-loudness levels from the fitted loudness functions were compared to the model predictions. The loudness model was qualitatively consistent with the behavioral data. The model predicted SSN to be louder than vowels and spondees which would be louder than tones; however, the model over-predicted the loudness differences. Possible explanations for the over-prediction include biases in loudness judgments, cognitive factors regarding learned expectations for loudness, assumptions regarding the free-field-to-headphone transfer function, and the model’s over-prediction of spectral, loudness summation, a result found recently (Schlittenlacher et al., 2014) for the ANSI standard and DIN 45631.

Correspondences among pupillary dilation response, subjective salience of sounds, and loudness.

A pupillary dilation response is known to be evoked by salient deviant or contrast auditory stimuli, but so far a direct link between it and subjective salience has been lacking. In two experiments, participants listened to various environmental sounds while their pupillary responses were recorded. In separate sessions, participants performed subjective pairwise-comparison tasks on the sounds with respect to their salience, loudness, vigorousness, preference, beauty, annoyance, and hardness. The pairwise-comparison data were converted to ratings on the Thurstone scale. The results showed a close link between subjective judgments of salience and loudness. The pupil dilated in response to the sound presentations, regardless of sound type. Most importantly, this pupillary dilation response to an auditory stimulus positively correlated with the subjective salience, as well as the loudness, of the sounds (Exp. 1). When the loudnesses of the sounds were identical, the pupil responses to each sound were similar and were not correlated with the subjective judgments of salience or loudness (Exp. 2). This finding was further confirmed by analyses based on individual stimulus pairs and participants. In Experiment 3, when salience and loudness were manipulated by systematically changing the sound pressure level and acoustic characteristics, the pupillary dilation response reflected the changes in both manipulated factors. A regression analysis showed a nearly perfect linear correlation between the pupillary dilation response and loudness. The overall results suggest that the pupillary dilation response reflects the subjective salience of sounds, which is defined, or is heavily influenced, by loudness.

A Sound Therapy-Based Intervention to Expand the Auditory Dynamic Range for Loudness among Persons with Sensorineural Hearing Losses: A Randomized Placebo-Controlled Clinical Trial.

The primary aim of this research was to evaluate the validity, efficacy, and generalization of principles underlying a sound therapy-based treatment for promoting expansion of the auditory dynamic range (DR) for loudness. The basic sound therapy principles, originally devised for treatment of hyperacusis among patients with tinnitus, were evaluated in this study in a target sample of unsuccessfully fit and/or problematic prospective hearing aid users with diminished DRs (owing to their elevated audiometric thresholds and reduced sound tolerance). Secondary aims included: (1) delineation of the treatment contributions from the counseling and sound therapy components to the full-treatment protocol and, in turn, the isolated treatment effects from each of these individual components to intervention success; and (2) characterization of the respective dynamics for full, partial, and control treatments. Thirty-six participants with bilateral sensorineural hearing losses and reduced DRs, which affected their actual or perceived ability to use hearing aids, were enrolled in and completed a placebo-controlled (for sound therapy) randomized clinical trial. The 2 × 2 factorial trial design was implemented with or without various assignments of counseling and sound therapy. Specifically, participants were assigned randomly to one of four treatment groups (nine participants per group), including: (1) group 1-full treatment achieved with scripted counseling plus sound therapy implemented with binaural sound generators; (2) group 2-partial treatment achieved with counseling and placebo sound generators (PSGs); (3) group 3-partial treatment achieved with binaural sound generators alone; and (4) group 4-a neutral control treatment implemented with the PSGs alone. Repeated measurements of categorical loudness judgments served as the primary outcome measure. The full-treatment categorical-loudness judgments for group 1, measured at treatment termination, were significantly greater than the corresponding pretreatment judgments measured at baseline at 500, 2,000, and 4,000 Hz. Moreover, increases in their "uncomfortably loud" judgments (∼12 dB over the range from 500 to 4,000 Hz) were superior to those measured for either of the partial-treatment groups 2 and 3 or for control group 4. Efficacy, assessed by treatment-related criterion increases ≥ 10 dB for judgments of uncomfortable loudness, was superior for full treatment (82% efficacy) compared with that for either of the partial treatments (25% and 40% for counseling combined with the placebo sound therapy and sound therapy alone, respectively) or for the control treatment (50%). The majority of the group 1 participants achieved their criterion improvements within 3 months of beginning treatment. The treatment effect from sound therapy was much greater than that for counseling, which was statistically indistinguishable in most of our analyses from the control treatment. The basic principles underlying the full-treatment protocol are valid and have general applicability for expanding the DR among individuals with sensorineural hearing losses, who may often report aided loudness problems. The positive full-treatment effects were superior to those achieved for either counseling or sound therapy in virtual or actual isolation, respectively; however, the delivery of both components in the full-treatment approach was essential for an optimum treatment outcome.

Perceptual weights for loudness judgments of six-tone complexes.

Subjects with normal hearing (NH) and with sensorineural hearing loss (SNHL) judged the overall loudness of six-tone complexes comprised of octave frequencies from 0.25 to 8 kHz. The level of each tone was selected from a normal distribution with a standard deviation of 5 dB, and subjects judged which of two complexes was louder. Overall level varied across conditions. In the "loudness" task, there was no difference in mean level across the two stimuli. In the "sample discrimination" task, the two complexes differed by an average of 5 dB. For both tasks, perceptual weights were derived by correlating the differences in level between matched-frequency tones in the complexes and the loudness decision on each trial. Weights obtained in the two tasks showed similar shifts from low to high frequency components with increasing overall level. Simulation of these experiments using a model of loudness perception [Moore and Glasberg (2004), Hear Res. 188, 70-88] yielded predicted weights for these stimuli that were highly correlated with predicted specific loudness, but not with the observed weights.

Plasticity and modified loudness following short-term unilateral deprivation: Evidence of multiple gain mechanisms within the auditory system

Auditory deprivation and stimulation can change the threshold of the acoustic middle ear reflex as well as loudness in adult listeners. However, it has remained unclear whether changes in these measures are due to the same mechanism. In this study, deprivation was achieved using a monaural earplug that was worn by listeners for 7 days. Acoustic reflex thresholds (ARTs) and categorical loudness ratings were measured using a blinded design in which the experimenter was unaware of which ear had been plugged. Immediately after terminating unilateral deprivation, ARTs were obtained at a lower sound pressure level in the ear that had been fitted with an earplug and at a higher sound pressure level in the control ear. In contrast, categorical judgments of loudness changed in the same direction in both ears with a given stimulus level reported as louder after unilateral deprivation. The relationship between changes to the ART and loudness judgments was not statistically significant. For both the ARTs and the categorical loudness judgments, most of the changes had disappeared within 24 h after earplug removal. The changes in ARTs, as a consequence of unilateral sound deprivation, are consistent with a gain control mechanism; however, the lack of relationship with the categorical loudness judgments, and the different pattern of findings for each measure, suggests the possibility of multiple gain mechanisms.

Equal loudness contours and possible weighting functions for pinnipeds

The idea of developing frequency weighting functions for marine mammals has received considerable attention recently because such functions can determine the relevant bandwidth for noise exposure assessments, and because they take differences in auditory sensitivity between species into account when identifying acoustic risks. However, such weighting functions are difficult to establish for nonhumans as they rely on equal loudness relationships that are subjective. Equal auditory reaction times may serve as a proxy for equal loudness judgments. For this experiment, we measured frequency-specific latency-intensity (L-I) functions for one California sea lion and one harbor seal with tones that were + 0, + 2, + 4, + 6, + 10, + 20, + 30, and + 40 dB re: sensation level (SL). The L-I plots were reliably fit with a power function to enable the determination of sound pressure levels corresponding to discrete latency values for each subject at each frequency. From these data, equal latency contours were drawn to describe differential auditory sensitivity as a function of frequency. The weighting functions derived from these contours are less conservative than the currently proposed “m”-weighting function for marine mammals, and may be more reliable than the alternative inverted audiogram approach. [Work supported by ONR.]

Distinct Features of Auditory Steady-State Responses as Compared to Transient Event-Related Potentials

Transient event-related potentials (ERPs) and steady-state responses (SSRs) have been popularly employed to investigate the function of the human brain, but their relationship still remains a matter of debate. Some researchers believed that SSRs could be explained by the linear summation of successive transient ERPs (superposition hypothesis), while others believed that SSRs were the result of the entrainment of a neural rhythm driven by the periodic repetition of a sensory stimulus (oscillatory entrainment hypothesis). In the present study, taking auditory modality as an example, we aimed to clarify the distinct features of SSRs, evoked by the 40-Hz and 60-Hz periodic auditory stimulation, as compared to transient ERPs, evoked by a single click. We observed that (1) SSRs were mainly generated by phase synchronization, while late latency responses (LLRs) in transient ERPs were mainly generated by power enhancement; (2) scalp topographies of LLRs in transient ERPs were markedly different from those of SSRs; (3) the powers of both 40-Hz and 60-Hz SSRs were significantly correlated, while they were not significantly correlated with the N1 power in transient ERPs; (4) whereas SSRs were dominantly modulated by stimulus intensity, middle latency responses (MLRs) were not significantly modulated by both stimulus intensity and subjective loudness judgment, and LLRs were significantly modulated by subjective loudness judgment even within the same stimulus intensity. All these findings indicated that high-frequency SSRs were different from both MLRs and LLRs in transient ERPs, thus supporting the possibility of oscillatory entrainment hypothesis to the generation of SSRs. Therefore, SSRs could be used to explore distinct neural responses as compared to transient ERPs, and help us reveal novel and reliable neural mechanisms of the human brain.

Music of the body: An investigation of skull resonance and its influence on musical preferences

Musical preferences can be attributed to environmental and biological factors. This research analyzes the specific influence of body resonance, and in particular, how the resonant properties of the skull might contribute to auditory perception of music and musical preferences. To examine this issue resonances were sampled from a set of participants and analyzed using FFTs. The fundamental frequencies of each participant’s head was correlated against their preference amongst a set of novel melodies presented in each of the 12 major keys. Using this method the spectral properties of the melody could be directly related to the resonant properties of a listener’s skull to evaluate their influence. While results were subtle, participants were found to be influenced in their judgments of loudness and musical preference for the melodies. Conclusions from this research support speculation on an embodied model of cognition for musical interactions.

Quality and loudness judgments for music subjected to compression limiting

Dynamic-range compression (DRC) is used in the music industry to maximize loudness. The amount of compression applied to commercial recordings has increased over time due to a motivating perspective that louder music is always preferred. In contrast to this viewpoint, artists and consumers have argued that using large amounts of DRC negatively affects the quality of music. However, little research evidence has supported the claims of either position. The present study investigated how DRC affects the perceived loudness and sound quality of recorded music. Rock and classical music samples were peak-normalized and then processed using different amounts of DRC. Normal-hearing listeners rated the processed and unprocessed samples on overall loudness, dynamic range, pleasantness, and preference, using a scaled paired-comparison procedure in two conditions: un-equalized, in which the loudness of the music samples varied, and loudness-equalized, in which loudness differences were minimized. Results indicated that a small amount of compression was preferred in the un-equalized condition, but the highest levels of compression were generally detrimental to quality, whether loudness was equalized or varied. These findings are contrary to the "louder is better" mentality in the music industry and suggest that more conservative use of DRC may be preferred for commercial music.

Visual distance cues modulate neuromagnetic auditory N1m responses

ObjectiveAuditory distance judgment relies on several acoustic cues and can be modulated by visual information. Sound intensity serves as one such cue as it decreases with increasing distance. In this magnetoencephalography (MEG) experiment, we tested whether N1m MEG responses, previously described to scale with sound intensity, are modulated by visual distance cues. MethodsWe recorded behavioral and MEG data from 15 healthy normal hearing participants. Noise bursts at different sound pressure levels were paired with synchronous visual cues at different distances. We hypothesized that noise paired with far visual cues will be represented louder and result in increased N1m amplitudes compared to a pairing with close visual cues. This might be based on a compensation of visually induced distance when processing loudness. ResultsPsychophysically, we observed no significant modulation of loudness judgments by visual cues. However, N1m MEG responses at about 100ms after stimulus onset were significantly stronger with distal compared to proximal visual cues in the left auditory cortex. ConclusionsOur results suggest an audio–visual interaction at an early stage in the left auditory cortex, possibly related to cue integration for auditory distance processing. SignificanceSound distance processing could prove itself as a promising model system for the investigation of intra-modal and cross-modal integration principles.

Optimization of Programming Parameters in Children with the Advanced Bionics Cochlear Implant

Cochlear implants provide access to soft intensity sounds and therefore improved audibility for children with severe-to-profound hearing loss. Speech processor programming parameters, such as threshold (or T-level), input dynamic range (IDR), and microphone sensitivity, contribute to the recipient's program and influence audibility. When soundfield thresholds obtained through the speech processor are elevated, programming parameters can be modified to improve soft sound detection. Adult recipients show improved detection for low-level sounds when T-levels are set at raised levels and show better speech understanding in quiet when wider IDRs are used. Little is known about the effects of parameter settings on detection and speech recognition in children using today's cochlear implant technology. The overall study aim was to assess optimal T-level, IDR, and sensitivity settings in pediatric recipients of the Advanced Bionics cochlear implant. Two experiments were conducted. Experiment 1 examined the effects of two T-level settings on soundfield thresholds and detection of the Ling 6 sounds. One program set T-levels at 10% of most comfortable levels (M-levels) and another at 10 current units (CUs) below the level judged as "soft." Experiment 2 examined the effects of IDR and sensitivity settings on speech recognition in quiet and noise. Participants were 11 children 7-17 yr of age (mean 11.3) implanted with the Advanced Bionics High Resolution 90K or CII cochlear implant system who had speech recognition scores of 20% or greater on a monosyllabic word test. Two T-level programs were compared for detection of the Ling sounds and frequency modulated (FM) tones. Differing IDR/sensitivity programs (50/0, 50/10, 70/0, 70/10) were compared using Ling and FM tone detection thresholds, CNC (consonant-vowel nucleus-consonant) words at 50 dB SPL, and Hearing in Noise Test for Children (HINT-C) sentences at 65 dB SPL in the presence of four-talker babble (+8 signal-to-noise ratio). Outcomes were analyzed using a paired t-test and a mixed-model repeated measures analysis of variance (ANOVA). T-levels set 10 CUs below "soft" resulted in significantly lower detection thresholds for all six Ling sounds and FM tones at 250, 1000, 3000, 4000, and 6000 Hz. When comparing programs differing by IDR and sensitivity, a 50 dB IDR with a 0 sensitivity setting showed significantly poorer thresholds for low frequency FM tones and voiced Ling sounds. Analysis of group mean scores for CNC words in quiet or HINT-C sentences in noise indicated no significant differences across IDR/sensitivity settings. Individual data, however, showed significant differences between IDR/sensitivity programs in noise; the optimal program differed across participants. In pediatric recipients of the Advanced Bionics cochlear implant device, manually setting T-levels with ascending loudness judgments should be considered when possible or when low-level sounds are inaudible. Study findings confirm the need to determine program settings on an individual basis as well as the importance of speech recognition verification measures in both quiet and noise. Clinical guidelines are suggested for selection of programming parameters in both young and older children.

Auditory perception of natural sound categories – An fMRI study

Despite an extremely rich and complex auditory environment, human beings categorize sounds effortlessly. While it is now well-known that this ability is a result of complex interaction of bottom-up processing of low-level acoustic features and top-down influences like evolutionary relevance, it is yet unclear how these processes drive categorization. The objective of the current study was to use functional neuroimaging to investigate the contribution of these two processes for category selectivity in the cortex. We used a set of ecologically valid sounds that belonged to three different categories: animal vocalizations, environmental sounds and human non-speech sounds, all matched on acoustic structure attributes like harmonic-to-noise ratio to minimize differences in bottom-up processing as well as matched for familiarity to rule out other top-down influences. Participants performed a loudness judgment task in the scanner and data were acquired using a sparse-temporal sampling paradigm. Our functional imaging results show that there is category selectivity in the cortex only for species-specific vocalizations and this is revealed in six clusters in the right and left STG/STS. Category selectivity was not observed for any other category of sounds. Our findings suggest a potential role of evolutionary relevance for cortical processing of sounds. While this seems to be an appealing proposition, further studies are required to explore the role of top-down mechanisms arising from such features to drive category selectivity in the brain.

Loudness asymmetry in real-room reverberation: cross-band effects

Although room reverberation adds sizeable “tails” at the ends of sounds, they are not prominent for listeners. Evidence for this comes from loudness judgements of stimuli with envelopes having fast onsets and slow offsets, thereby resembling sounds with reverberant tails. Such sounds are less loud than their reversed counterparts, and this difference is more substantial when the test-sound is preceded by a “standard” sound that has a similarly “tail-like” offset. A perceptual constancy may be responsible; one where sounds with decaying tails are “parsed” to separate source characteristics from effects of reverberation, and to discount energy in tails from listeners' judgements. Indeed, this “loudness context effect” is even more substantial when real-room reverberation is used. Here we ask whether the effect is restricted to the frequency region occupied by the context; conditions where standard and tests occupy the same narrowband frequency region are compared with “cross-band” conditions, where the stan...

Visual Distance Cues Amplify Neuromagnetic Auditory N1m Responses

Ranging of auditory objects relies on several acoustic cues and is possibly modulated by additional visual information. Sound pressure level can serve as a cue for distance perception because it decreases with increasing distance. In this agnetoencephalography (MEG) experiment, we tested whether psychophysical loudness judgment and N1m MEG responses are modulated by visual distance cues. To this end, we paired noise bursts at different sound pressure levels with synchronous visual cues at different distances. We hypothesized that noise bursts paired with far visual cues will be perceived louder and result in increased N1m amplitudes compared to a pairing with close visual cues. The rationale behind this was that listeners might compensate the visually induced object distance when processing loudness. Psychophysically, we observed no significant modulation of loudness judgments by visual cues. However, N1m MEG responses at about 100 ms after stimulus onset were significantly stronger for far versus close v...

Right temporal TMS impairs voice detection

Summary Functional magnetic resonance imaging (fMRI) research has revealed bilateral cortical regions along the upper banks of the superior temporal sulci (STS) which respond preferentially to voices compared to non-vocal, environmental sounds [1,2]. This sensitivity is particularly pronounced in the right hemisphere. Voice perception models imply that these regions, referred to as the temporal voice areas (TVAs), could correspond to a first stage of voice-specific processing in auditory cortex [3,4], after which different types of vocal information are processed in interacting but partially independent functional pathways. However, clear causal evidence for this claim is missing. Here we provide the first direct link between TVA activity and voice detection ability using repetitive transcranial magnetic stimulation (rTMS). Voice/non-voice discrimination ability was impaired when rTMS was targeted at the right TVA compared with a control site. In contrast, a lower-level loudness judgement task was not differentially affected by site of stimulation. Results imply that neuronal computations in the right TVA are necessary for the distinction between human voices and other, non-vocal sounds.

Neural Processing of What and Who Information in Speech

Human speech is composed of two types of information, related to content (lexical information, i.e., "what" is being said [e.g., words]) and to the speaker (indexical information, i.e., "who" is talking [e.g., voices]). The extent to which lexical versus indexical information is represented separately or integrally in the brain is unresolved. In the current experiment, we use short-term fMRI adaptation to address this issue. Participants performed a loudness judgment task during which single or multiple sets of words/pseudowords were repeated with single (repeat) or multiple talkers (speaker-change) conditions while BOLD responses were collected. As reflected by adaptation fMRI, the left posterior middle temporal gyrus, a crucial component of the ventral auditory stream performing sound-to-meaning computations ("what" pathway), showed sensitivity to lexical as well as indexical information. Previous studies have suggested that speaker information is abstracted during this stage of auditory word processing. Here, we demonstrate that indexical information is strongly coupled with word information. These findings are consistent with a plethora of behavioral results that have demonstrated that changes to speaker-related information can influence lexical processing.

Feasibility of group voice therapy for individuals with Parkinson's disease

Purpose The primary purpose was to demonstrate the feasibility of executing treatment tasks focused on increasing loudness in a group format for individuals with Parkinson's disease (PD). A second purpose was to report preliminary pre-to-post treatment outcomes for individuals with PD immediately after they complete the group program. Methods The group intervention is described. Fifteen adults with PD who participated in the group and three clinicians leading the group provided feedback about the execution of the intervention. The participants also provided voice samples and self-ratings of voice handicap once before completing the 8-week voice group and once immediately after completing the voice group. Outcome measures included voice intensity, fundamental frequency (F0) mean, standard deviation and range, maximum phonation time, and listener judgment of loudness. Results Feedback from the clinicians suggested that many, but not all, of the voice activities could be executed within a group setting. Participants with PD indicated they understood the focus of the group and that subjectively they felt the group was helpful for increasing loudness. Statistically significant increases occurred for voice intensity, F0 maximum, and F0 range. Voice handicap scores decreased significantly and 80% of the participants were judged louder post intervention. Conclusions Clinician and participant feedback indicated that it was feasible to execute most LSVT ® tasks in a group format with some modifications. The preliminary outcome data indicate that the targeted behavior (voice dB and loudness) did change in the predicted direction as did several other measures. Future studies comparing outcomes of group intervention to the gold standard LSVT ®, and exploring retention of treatment gains over time, are needed. Learning outcomes: After reading the manuscript, readers will be able to: (1) Describe previous attempts at group intervention to improve voice for individuals with Parkinson's disease. (2) List three ways that the group intervention tried in this study differed from LSVT ®. (3) Identify three limitations to this study that must be addressed before advocating implementation of the group approach in clinical situations.

Perceptual constancy for real‐room reverberation in loudness judgements and the effects of interstimulus interval.

Narrowband stimuli shaped with fast‐onset and slow‐offset temporal envelopes are judged to be less loud than their reversed counterparts, particularly when preceded by a slow‐offset standard. It has been suggested that a “perceptual constancy” may be responsible for this “loudness context effect.” The idea is that when a slow‐offset “tail” is at the end of a sound it is largely attributed to listening‐environment reflections and is discounted in the listener’s loudness judgment. Previous experiments have shown that this effect is even bigger when real‐room reflection‐patterns are used. The present experiments varied the interval between the standard and comparison tones (ISI) to investigate the contribution of time‐order effects to these loudness judgements. Such effects might arise as the peak‐to‐peak interval between sounds changes with reversal of the standard, thereby confounding the duration of this interval with the presence of a “tail” in the standard. Results show that the loudness context effect reported earlier remains prominent across a range of ISI times and that the influence of any time‐order effects is relatively weak. Consequently, these findings remain consistent with the idea that the context effect arises through a perceptual constancy. [Work supported by EPSRC.]

Pitch and loudness interactions between audition and touch.

Sensory signals combine and interact to produce stable representations of our environment. Audition and touch both convey information about environmental oscillations. We hypothesized that the two modalities interact in the perception of sounds and vibrations. We conducted a series of psychophysical experiments to explore how auditory and tactile signals interact in frequency and intensity perception. We found that audio‐tactile pitch interactions are bidirectional, as distractors influence frequency perception regardless of the attended modality. In contrast, we found that loudness interactions depend on the attended modality: Tactile distractors influence judgments of auditory loudness, but judgments of tactile intensity are impervious to auditory distractions. We also found that audio‐tactile pitch and loudness interactions differ in their sensitivity to stimulus timing. These results reveal that auditory and tactile inputs combine differently depending on the perceptual task. That distinct rules govern the integration of auditory and tactile signals in pitch and loudness perception implies that the two rely on separate neural mechanisms.

Influence of Train Colour on Loudness Judgments

This study replicates an experiment described by Patsouras et al. [5] or Rader et al. [8] in which subjects had to evaluate the loudness of a passing-by train noise while watching pictures of the train, the colour of which being varied. In contrast to these studies, no influence of train colour on loudness evaluation could be found. This discrepancy might be due to cultural differences (French subjects vs. German or Japanese ones). But a more realistic reason can be a jury sampling effect, as this influence can exist for very few subjects (one among twenty-two in this experiment).