Outstanding questions concerning the regulation of enhancement devices

The authors (Maslen et al., 2014) propose to regulate cognitive enhancement devices (CEDs) as medical devices. Extending medical device regulations to CEDs raises some important questions that need to be adequately addressed before it makes sense to pursue this path. A first problem concerns the definition of ‘cognitive enhancement’ and ‘CEDs’. Where does treatment end and enhancement begin? Secondly, since most CEDs such as neurofeedback and transcranial direct current stimulation are currently performed by non-medical health care providers, how will this regulation impact the current practice, and which requirements need to be put in place to regulate their use? Thirdly, distributive justice issues present an obvious ethical limitation. Fourthly, if CEDs are indeed prescribed off-label similar to the off-label prescription of psychopharmacological enhancers by MDs, this will pose problems regarding a lack of sufficient knowledge and expertise due to the highly specialized nature of CEDs. And finally, are we faced with unnecessary worries and unrealistic hopes when it comes to CEDs? In sum, we propose to regulate them regarding product safety and restrict them to competent adult use including professional oversight where indicated

The auditory and non-auditory brain areas involved in tinnitus. An emergent property of multiple parallel overlapping subnetworks

Tinnitus is the perception of a sound in the absence of an external sound source. It is characterized by sensory components such as the perceived loudness, the lateralization, the tinnitus type (pure tone, noise-like) and associated emotional components, such as distress and mood changes. Source localization of quantitative electroencephalography (qEEG) data demonstrate the involvement of auditory brain areas as well as several non-auditory brain areas such as the anterior cingulate cortex (dorsal and subgenual), auditory cortex (primary and secondary), dorsal lateral prefrontal cortex, insula, supplementary motor area, orbitofrontal cortex (including the inferior frontal gyrus), parahippocampus, posterior cingulate cortex and the precuneus, in different aspects of tinnitus. Explaining these non-auditory brain areas as constituents of separable subnetworks, each reflecting a specific aspect of the tinnitus percept increases the explanatory power of the non-auditory brain areas involvement in tinnitus. Thus, the unified percept of tinnitus can be considered an emergent property of multiple parallel dynamically changing and partially overlapping subnetworks, each with a specific spontaneous oscillatory pattern and functional connectivity signature

Head-to-Head Comparison of Transcranial Random Noise Stimulation, Transcranial AC Stimulation, and Transcranial DC Stimulation for Tinnitus

Tinnitus is the perception of a sound in the absence of an external sound stimulus. This phantom sound has been related to plastic changes and hyperactivity in the auditory cortex. Different neuromodulation techniques such as transcranial magnetic stimulation and transcranial direct current stimulation (tDCS) have been used in an attempt to modify local and distant neuroplasticity as to reduce tinnitus symptoms. Recently, two techniques of pulsed electrical stimulation using weak electrical currents – transcranial alternating current stimulation (tACS) and transcranial random noise stimulation (tRNS) – have also shown significant neuromodulatory effects. In the present study we conducted the first head-to-head comparison of three different transcranial electrical stimulation (tES) techniques, namely tDCS, tACS, and tRNS in 111 tinnitus patients by placing the electrodes overlying the auditory cortex bilaterally. The results demonstrated that tRNS induced the larger transient suppressive effect on the tinnitus loudness and the tinnitus related distress as compared to tDCS and tACS. Both tDCS and tACS induced small and non-significant effects on tinnitus symptoms, supporting the superior effects of tRNS as a method for tinnitus suppression

Pinpointing a highly specific pathological functional connection that turns phantom sound into distress

International audienceIt has been suggested that an auditory phantom percept is the result of multiple, parallel but overlapping networks. One of those networks encodes tinnitus loudness and is electrophysiologically separable from a non-specific distress network. The present study investigates how these networks anatomically overlap, what networks are involved and how and when these networks interact. The EEG data of 317 tinnitus patients and 256 healthy subjects were analyzed, using independent component analysis. Results demonstrate that tinnitus is characterized by at least two major brain networks, each consisting of multiple independent components. One network reflects tinnitus distress, while another network reflects the loudness of the tinnitus. The component coherence analysis shows that the independent components that make up the distress and loudness networks communicate within their respective network at several discrete frequencies in parallel. The distress and loudness networks do not intercommunicate for patients without distress, but do when patients are distressed by their tinnitus. The obtained data demonstrate that the components that build up these two separable networks communicate at discrete frequencies within the network, and only between the distress and loudness networks in those patients in whom the symptoms are also clinically linked

A Bayesian approach to adaptive frequency sampling

This paper introduces an adaptive frequency sampling scheme, based on a Bayesian approach to the well-known vector fitting algorithm. This Bayesian treatment results in a data-driven measure of intrinsic model uncertainty. This uncertainty measure can in turn be leveraged to sample sequentially in an efficient and robust way. A realistic example is used to visualize the proposed scheme, and to confirm its proficiency

Urothelial TRPV1: TRPV1-Reporter Mice, a Way to Clarify the Debate?

A commentary on Trpv1 reporter mice reveal highly restricted brain distribution and functional expression in arteriolar smooth muscle cell

Tinnitus: Clinical Insights in Its Pathophysiology-A Perspective

Tinnitus, the perception of sound without a corresponding external sound source, and tinnitus disorder, which is tinnitus with associated suffering, present a multifaceted clinical challenge due to its heterogeneity and its incompletely understood pathophysiology and especially due to the limited therapeutic options. In this narrative review, we give an overview on various clinical aspects of tinnitus including its heterogeneity, contributing factors, comorbidities and therapeutic pathways with a specific emphasis on the implications for its pathophysiology and future research directions. Tinnitus exhibits high perceptual variability between affected individuals (heterogeneity) and within affected individuals (temporal variability). Hearing loss emerges as predominant risk factor and the perceived pitch corresponds to areas of hearing loss, supporting the compensatory response theory. Whereas most people who have tinnitus can live a normal life, in 10–20% tinnitus interferes severely with quality of life. These patients suffer frequently from comorbidities such as anxiety, depression or insomnia, acting as both risk factors and consequences. Accordingly, neuroimaging studies demonstrate shared brain networks between tinnitus and stress-related disorders shedding light on the intricate interplay of mental health and tinnitus. The challenge lies in deciphering causative relationships and shared pathophysiological mechanisms. Stress, external sounds, time of day, head movements, distraction, and sleep quality can impact tinnitus perception. Understanding these factors provides insights into the interplay with autonomic, sensory, motor, and cognitive processes. Counselling and cognitive-behavioural therapy demonstrate efficacy in reducing suffering, supporting the involvement of stress and anxiety-related networks. Hearing improvement, especially through cochlear implants, reduces tinnitus and thus indirectly validates the compensatory nature of tinnitus. Brain stimulation techniques can modulate the suffering of tinnitus, presumably by alteration of stress-related brain networks. Continued research is crucial for unravelling the complexities of tinnitus. Progress in management hinges on decoding diverse manifestations, identifying treatment-responsive subtypes, and advancing targeted therapeutic approaches

A parahippocampal-sensory Bayesian vicious circle generates pain or tinnitus: a source-localized EEG study

Pain and tinnitus share common pathophysiological mechanisms, clinical features, and treatment approaches. A source-localized resting-state EEG study was conducted in 150 participants: 50 healthy controls, 50 pain, and 50 tinnitus patients. Resting-state activity as well as functional and effective connectivity was computed in source space. Pain and tinnitus were characterized by increased theta activity in the pregenual anterior cingulate cortex, extending to the lateral prefrontal cortex and medial anterior temporal lobe. Gamma-band activity was increased in both auditory and somatosensory cortex, irrespective of the pathology, and extended to the dorsal anterior cingulate cortex and parahippocampus. Functional and effective connectivity were largely similar in pain and tinnitus, except for a parahippocampal-sensory loop that distinguished pain from tinnitus. In tinnitus, the effective connectivity between parahippocampus and auditory cortex is bidirectional, whereas the effective connectivity between parahippocampus and somatosensory cortex is unidirectional. In pain, the parahippocampal-somatosensory cortex is bidirectional, but parahippocampal auditory cortex unidirectional. These modality-specific loops exhibited theta-gamma nesting. Applying a Bayesian brain model of brain functioning, these findings suggest that the phenomenological difference between auditory and somatosensory phantom percepts result from a vicious circle of belief updating in the context of missing sensory information. This finding may further our understanding of multisensory integration and speaks to a universal treatment for pain and tinnitus-by selectively disrupting parahippocampal-somatosensory and parahippocampal-auditory theta-gamma activity and connectivity

Whole scalp EEG power change is not a prerequisite for further EEG processing

International audienceNon

Minimal Clinically Important Difference of Tinnitus Outcome Measurement Instruments—A Scoping Review

Objective: Tinnitus assessment and outcome measurement are complex, as tinnitus is a purely subjective phenomenon. Instruments used for the outcome measurement of tinnitus in the context of clinical trials include self-report questionnaires, visual analogue or numeric rating scales and psychoacoustic measurements of tinnitus loudness. For the evaluation of therapeutic interventions, it is critical to know which changes in outcome measurement instruments can be considered as clinically relevant. For this purpose, the concept of the minimal clinically important difference (MCID) has been introduced. Study design: Here we performed a literature research in PubMed in order to identify for which tinnitus outcome measurements MCID criteria have been estimated and which of these estimates fulfil the current methodological standards and can thus be considered as established. Results: For most, but not all tinnitus outcome instruments, MCID calculations have been performed. The MCIDs for the Tinnitus Handicap Inventory (THI), the Tinnitus Questionnaire (TQ), the Tinnitus Functional Index (TFI) and visual analogue scales (VAS) vary considerably across studies. Psychoacoustic assessments of tinnitus such as loudness matching have not shown sufficient reliability and validity for the use as an outcome measurement. Conclusion: Future research should aim at the confirmation of the available estimates in large samples involving various therapeutic interventions and under the consideration of time intervals and baseline values. As a rule of thumb, an improvement of about 15% can be considered clinically meaningful, analogous to what has been seen in other entirely subjective pathologies like chronic pain