EEG activity as an objective measure of cognitive load during effortful listening: A study on pediatric subjects with bilateral, asymmetric sensorineural hearing loss

Objectives: Deaf subjects with hearing aids or cochlear implants generally find it challenging to understand speech in noisy environments where a great deal of listening effort and cognitive load are invested. In prelingually deaf children, such difficulties may have detrimental consequences on the learning process and, later in life, on academic performance. Despite the importance of such a topic, currently, there is no validated test for the assessment of cognitive load during audiological tasks. Recently, alpha and theta EEG rhythm variations in the parietal and frontal areas, respectively, have been used as indicators of cognitive load in adult subjects. The aim of the present study was to investigate, by means of EEG, the cognitive load of pediatric subjects affected by asymmetric sensorineural hearing loss as they were engaged in a speech-in-noise identifi- cation task. Methods: Seven children (4F and 3M, age range ¼ 8e16 years) affected by asymmetric sensorineural hearing loss (i.e. profound degree on one side, mild-to-severe degree on the other side) and using a hearing aid only in their better ear, were included in the study. All of them underwent EEG recording during a speech-in-noise identification task: the experimental conditions were quiet, binaural noise, noise to the better hearing ear and noise to the poorer hearing ear. The subjects' Speech Recognition Thresholds (SRT) were also measured in each test condition. The primary outcome measures were: frontal EEG Power Spectral Density (PSD) in the theta band and parietal EEG PSD in the alpha band, as assessed before stimulus (word) onset. Results: No statistically significant differences were noted among frontal theta power levels in the four test conditions. However, parietal alpha power levels were significantly higher in the “binaural noise” and in the “noise to worse hearing ear” conditions than in the “quiet” and “noise to better hearing ear” conditions (p < 0.001). SRT scores were consistent with task difficulty, but did not correlate with alpha and theta power level variations. Conclusion: This is the first time that EEG has been applied to children with sensorineural hearing loss with the purpose of studying the cognitive load during effortful listening. Significantly higher parietal alpha power levels in two of three noisy conditions, compared to the quiet condition, are consistent with increased cognitive load. Specifically, considering the time window of the analysis (pre-stimulus), parietal alpha power levels may be a measure of cognitive functions such as sustained attention and selective inhibition. In this respect, the significantly lower parietal alpha power levels in the most challenging listening condition (i.e. noise to the better ear) may be attributed to loss of attention and to the subsequent fatigue and “withdrawal” from the task at hand

A pilot study on the neurometric evaluation of 'effective' and 'ineffective' antismoking public service announcements

.Tobacco use is the leading cause of preventable death and smoking - related illness worldwide. Research has shown that antismoking advertising may help reduce this habit. Nowadays, public service announcements (PSAs) are considered “Effective” or “Ineffectiv e” on the base of official reports concerning behavioral /attitudinal changes toward healthier patterns and health - related savings following the exposure to the PSA. In this pilot study, we described the results of the use of three neurometric indexes for t he evaluation of the efficacy of a couple of antismoking PSAs in a reduced sample of voluntary participants. The study applied the gathering of the electroencephalographic (EEG) rhythms variations, as well as the heart rate (HR) and galvanic skin response (GSR). The neurometric indicators here employed were the Approach - Withdrawal (AW), the Effort (EfI) and the Emotional (EI) indexes. Results suggest a significant higher values for AW, Effort and Emotional indexes (p=0,02 ; p= 0,03 and p= 0,01 respectively) related to the perception of the “ Effective ” antismoking PSAs against the perception of the “ Ineffective ” one . Since this is a pilot study, the results obtained need further investigation, in terms of enlarged stimuli sample and number of participant s to p rovide indications concerning the relevant features to be included in the realization of effective anti - smoking PSAs

An eye tracking index for the salience estimation in visual stimuli

Every day we face visual stimuli able to catch our attention, but this aspect becomes crucial if the visual material has the purpose to spread a message aimed at engaging the observer. In this framework, a worthy aspect is how to measure the “visual engagement” produced by visual stimuli exposure. To this purpose, in the present study, employing the eye tracking technique, an index of visual attention (VA) has been proposed, and applied to pictures belonging to antismoking public service announcements, so to investigate the saliency of health-promoting messages in a young sample. The VA index is a non-dimensional index, defined as the ratio between the percentage of the total time spent fixating an area of interest (AOI) weighted on the total time the picture is showed on the screen, and the percentage of the area occupied by the AOI weighted on the total dimension of the picture. It could be predicted that AOI reporting higher VA values will be the ones having more saliency. Three antismoking Public Service Announcements (PSAs) images have been selected for the study and for each of them were identified: i) “picture” (such as a young man with a sarcastic expression depicted while smoking a cigarette, or the image of a lady who underwent a tracheotomy) and ii) “writing” (text of the antismoking message) AOIs. Main results of the analysis revealed that writing AOIs obtained statistically significant higher VA values than visual AOIs (p=0.03), but these held true only for an ineffective PSA, probably because the text was not perceived as pertinent with the surrounding image. On the other hand, an effective PSA obtained higher VA values in response to visual than writing AOIs observation (p=0.02). The VA index appears therefore to represent a useful tool to measure the saliency of visual stimuli elements.Social decision makin

Evaluation of different cochlear implants in unilateral hearing patients during word listening tasks: A brain connectivity study

Advanced methodologies used for the biomedical signal interpretation allow using cerebral signals to assess important cognitive functions in humans. In the present study, as parameter of cerebral effort, has been employed the isolated effective coherence, in order to estimate the effective connectivity and network organization. The hypothesis was that the lower the number of inter-connections engaged, the lower the cerebral effort induced by the experimental condition. In the present research this index has been applied to test the reaction to the use of different cochlear implant processors (Freedom, CP810 and CP910 - Cochlear Ltd), with the aim to identify the most performing device during a word in noise recognition task. Results support the capability of identifying the device eliciting less brain area connections. In particular, the CP910 was the processor inducing the lower number of inter-connections among the tested ones. This investigation appeared to be worthy, since representing a tool to identify devices that would make available user's cognitive resources for additional tasks, a matter susceptible of generalization to various fields of application. The employment of the cerebral signals therefore open the way to the evaluation of the impact of different sensors and prosthetic devices, also using connectivity measures