Frequency-Following Responses in Sensorineural Hearing Loss: A Systematic Review

PURPOSE

This systematic review aims to assess the impact of sensorineural hearing loss (SNHL) on various frequency-following response (FFR) parameters.

METHODS

Following PRISMA guidelines, a systematic review was conducted using PubMed, Web of Science, and Scopus databases up to January 2023. Studies evaluating FFRs in patients with SNHL and normal hearing controls were included.

RESULTS

Sixteen case-control studies were included, revealing variability in acquisition parameters. In the time domain, patients with SNHL exhibited prolonged latencies. The specific waves that were prolonged differed across studies. There was no consensus regarding wave amplitude in the time domain. In the frequency domain, focusing on studies that elicited FFRs with stimuli of 170 ms or longer, participants with SNHL displayed a significantly smaller fundamental frequency (F0). Results regarding changes in the temporal fine structure (TFS) were inconsistent.

CONCLUSION

Patients with SNHL may require more time for processing (speech) stimuli, reflected in prolonged latencies. However, the exact timing of this delay remains unclear. Additionally, when presenting longer stimuli (≥ 170 ms), patients with SNHL show difficulties tracking the F0 of (speech) stimuli. No definite conclusions could be drawn on changes in wave amplitude in the time domain and the TFS in the frequency domain. Patient characteristics, acquisition parameters, and FFR outcome parameters differed greatly across studies. Future studies should be performed in larger and carefully matched subject groups, using longer stimuli presented at the same intensity in dB HL for both groups, or at a carefully determined maximum comfortable loudness level.

Validation of the acoustic change complex (ACC) prediction model to predict speech perception in noise in adult patients with hearing loss: a study protocol

BACKGROUND

Speech perception tests are essential to measure the functional use of hearing and to determine the effectiveness of hearing aids and implantable auditory devices. However, these language-based tests require active participation and are influenced by linguistic and neurocognitive skills limiting their use in patients with insufficient language proficiency, cognitive impairment, or in children. We recently developed a non-attentive and objective speech perception prediction model: the Acoustic Change Complex (ACC) prediction model. The ACC prediction model uses electroencephalography to measure alterations in cortical auditory activity caused by frequency changes. The aim is to validate this model in a large-scale external validation study in adult patients with varying degrees of sensorineural hearing loss (SNHL) to confirm the high predictive value of the ACC model and to assess its test-retest reliability.

METHODS

A total of 80 participants, aged 18-65 years, will be enrolled in the study. The categories of severity of hearing loss will be used as a blocking factor to establish an equal distribution of patients with various degrees of sensorineural hearing loss. During the first visit, pure tone audiometry, speech in noise tests, a phoneme discrimination test, and the first ACC measurement will be performed. During the second visit (after 1-4 weeks), the same ACC measurement will be performed to assess the test-retest reliability. The acoustic change stimuli for ACC measurements consist of a reference tone with a base frequency of 1000, 2000, or 4000 Hz with a duration of 3000 ms, gliding to a 300-ms target tone with a frequency that is 12% higher than the base frequency. The primary outcome measures are (1) the level of agreement between the predicted speech reception threshold (SRT) and the behavioral SRT, and (2) the level of agreement between the SRT calculated by the first ACC measurement and the SRT of the second ACC measurement. Level of agreement will be assessed with Bland-Altman plots.

DISCUSSION

Previous studies by our group have shown the high predictive value of the ACC model. The successful validation of this model as an effective and reliable biomarker of speech perception will directly benefit the general population, as it will increase the accuracy of hearing evaluations and improve access to adequate hearing rehabilitation.

Prevalence of tinnitus and hyperacusis in 9-12-year-old children

OBJECTIVES

To estimate the prevalence of tinnitus and hyperacusis in children aged 9-12 years in Flanders, as well as to explore the associations with hearing abilities and listening behaviours.

DESIGN

A cross-sectional survey was undertaken in four different Flemish schools. The questionnaire was distributed among 415 children, with a response rate of 97.3%.

RESULTS

The prevalence of permanent tinnitus was 10.5% and of hyperacusis was 3.3%. The hyperacusis prevalence was higher in girls (p < .05). Some children reported effects of tinnitus in terms of anxiety (20.1%), sleep (36.5%), and concentration (24.8%). When listening to personal listening devices, 33.5% of the children reported to listen for at least 1 h at 60% or higher of the volume range. Moreover, 54.9% of children stated to never wear hearing protection.

CONCLUSIONS

Tinnitus and hyperacusis are prevalent in children aged 9-12 years. Some of these children might be overlooked and, as such, not receiving the required follow-up or counselling. Development of guidelines for the assessment of these auditory symptoms in children would help to determine the prevalence numbers with greater accuracy. Sensibility campaigns for safe listening are warranted, as more than half of the children never use hearing protection.

Suggestions for shaping tinnitus service provision in Western Europe: Lessons from the COVID-19 pandemic

BACKGROUND

Tinnitus severity has been exacerbated because of the COVID-19 pandemic and those with tinnitus require additional support. Such support should be informed by patient preferences and needs. The objective of this study was to gather information from individuals with tinnitus living in Europe to inform stakeholders of the (a) support they needed in relation to changes associated with the COVID-19 pandemic and (b) suggestions regarding tinnitus care for the future.

METHODS

A cross-sectional mixed method study design was used using closed and open-ended questions via an online survey. Data were gathered from 710 adults experiencing tinnitus in Western Europe, with the majority living in The Netherlands, Belgium and Sweden. Data were analysed using qualitative content analysis and descriptive statistics.

RESULTS

Those with tinnitus indicated the following support needs during the pandemic (a) support for tinnitus, (b) support for hearing-related difficulties, (c) social support and (d) pandemic-related support. Five directions for future tinnitus care were provided, namely, (a) need for understanding professional support and access to multidisciplinary experts, (b) greater range of therapies and resources, (c) access to more information about tinnitus, (d) prioritising tinnitus research and (e) more support for hearing protection and hearing loss prevention.

CONCLUSIONS

The findings point to the need for accessible (remote), patient-centred, suitable and evidence-based tinnitus care. Insights from the current study can be used by various stakeholders including clinical practitioners and tinnitus support services to ensure those with tinnitus have access to the help and support required in order to reduce service provision insufficiencies.

Identification of a Non-Linear Model as a New Method to Detect Expiratory Airflow Limitation in Mechanically Ventilated Patients

Expiratory flow limitation (EFL) can occur in mechanically ventilated patients with chronic obstructive pulmonary disease and other disorders. It leads to dynamic hyperinflation with ensuing deleterious consequences. Detecting EFL is thus clinically relevant. Easily applicable methods however lack this detection being routinely made in intensive care. Using a simple mathematical model, we propose a new method to detect EFL that does not require any intervention or modification of the ongoing therapeutic. The model consists in a monoalveolar representation of the respiratory system, including a collapsible airway that is submitted to periodic changes in pressure at the airway opening: EFL provokes a sharp expiratory increase in the resistance Rc of the collapsible airway. The model parameters were identified via the Levenberg-Marquardt method by fitting simulated data on the airway pressure and the flow signals recorded in 10 mechanically ventilated patients. A sensitivity study demonstrated that only 8/11 parameters needed to be identified, the remaining three being given reasonable physiological values. Flow-volume curves built at different levels of positive expiratory pressure, PEEP, during "PEEP trials" (stepwise increases in positive end-expiratory pressure to optimize ventilator settings) have shown evidence of EFL in three cases. This was concordant with parameter identification (high Rc during expiration for EFL patients). We conclude from these preliminary results that our model is a potential tool for the non-invasive detection of EFL in mechanically ventilated patients.

Positive end expiratory pressure and expiratory flow limitation: a model study

Patients suffering from chronic obstructive pulmonary diseases, frequently exhibit expiratory airflow limitation. We propose a mathematical model describing the mechanical behavior of the ventilated respiratory system. This model has to simulate applied positive end-expiratory pressure (PEEP) effects during expiration, a process used by clinicians to improve airflow. The proposed model consists of a nonlinear two-compartment system. One of the compartments represents the collapsible airways and mimics its dynamic compression, the other represents the lung and chest wall compartment. For all clinical conditions tested (n=16), the mathematical model simulates the removal of expiratory airflow limitation at PEEP lower than 70-80% of intrinsic end-expiratory pressure (PEEPi), i.e. the end-expiratory alveolar pressure (PAet) without PEEP. It also shows the presence of an optimal PEEP. The optimal PEEP contributes to decrease PAet from 7.4+/-0.9 (SD) to 5.4+/-0.9 hPa (p < 0.0001; mild flow limitation) and from 11.8+/-1.1 to 7.8+/-0.7 hPa (p < 0.0001; severe flow limitation). Resistance of the collapsible compartment is decreased from 53+/-7 to 8.2+/-5.9 hPa.L(-1).s (p < 0.0001; mild flow limitation) and from 80+/-11 to 6.9+/-5.4 hPa.L(-1).s (p < 0.0001; severe flow limitation). This simplistic mathematical model gives a plausible explanation of the expiratory airflow limitation removal with PEEP and a rationale to the practice of PEEP application to airflow limited patients.

[Selective activation of blood pressure monitoring alarms: effect of noise pollution in the intensive care unit]

OBJECTIVE

To evaluate a selective activation of sounding alarms on non-invasive blood pressure (BP) monitoring according to the patient haemodynamic status.

STUDY DESIGN

Prospective study.

METHODS

Activation of alarms on BP was regulated with a protocol. Sounding alarms were either inactivated when patient's haemodynamic status was stable (group 1), or activated when it was unstable (group 2). The frequency of BP measurement was one every 15 min. For all mean BP value recorded, the following criteria were analyzed: 1) normality of the value compared to ranges 65-115 mmHg in group 1 or compared to alarm thresholds in group 2; 2) consequences on the care and therapeutic; 3) delay when an abnormal value was detected and managed after more than 15 min.

RESULTS

1,674 hours of monitoring from 42 patients, allowed the analysis of 6,695 measurements of mean BP, 3,092 in group 1 and 3,603 in group 2. In group 1, 2,822 measurements were considered as normal and 3,094 measures in group 2. Eight measurements had consequences on therapeutic in group 1, with only one with delay in care giving. 287 measurements had consequences on therapeutic in group 2, 8 with delay in care giving. Six per cent of abnormal measurements in group 2 were managed with delay. This protocol reduced by 52% the production of sounding alarms on BP, without noxious effects for the patients.

CONCLUSION

Selective activation of sounding alarms on BP, according to the patient haemodynamic status, reduced noise pollution and could be one solution to improve monitoring efficiency in intensive care unit.

[Clinical evaluation of alarm efficieny in intensive care]

OBJECTIVE

To evaluate the efficiency of haemodynamic and respiratory monitoring system by a clinical analysis of the alarms.

STUDY DESIGN

Observational prospective study.

PATIENTS

25 patients who presented acute respiratory distress syndrome and who were monitored with haemodynamic and respiratory monitoring.

METHODS

Each minute, a bedside clinical observer analysed alarms from the monitoring according to detection or absence to clinical events. Four situations were defined to statistical descriptive analysis: a) false positive (FP); b) true positive (TP); c) false negative (FN); and d) true negative (TN). True positive alarm which induced consequences on patients care were also analysed.

RESULTS

15,013 minutes allowed the recordings of 3,665 alarms, 44% from arterial pressure, 17% from SpO2 and 12% from airways maximal pressure. 46% were false positive alarms inducing a noisy pollution. The positive predictive value PPV = TP/(TP + FP) of these alarms were respectively 51% for arterial pressure, 18% for SpO2 and 100% for Paw. Only 5% of true positive alarms induced consequences on patients care.

CONCLUSION

This protocol allowed the evaluation of monitoring efficiency. This kind of evaluation may help to improve monitoring capacity with reducing noisy pollution from false positive alarms.