Cerebral processing of auditory stimuli in patients with irritable bowel syndrome

AIM： To determine by brain functional magnetic resonance imaging （fMRI） whether cerebral processing of non-visceral stimuli is altered in irritable bowel syndrome （IBS） patients compared with healthy subjects. To circumvent spinal viscerosomatic convergence mechanisms, we used auditory stimulation, and to identify a possible influence of psychological factors the stimuli differed in their emotional quality. METHODS： In 8 IBS patients and 8 controls, fMRI measurements were performed using a block design of 4 auditory stimuli of different emotional quality （pleasant sounds of chimes, unpleasant peep （2000 Hz）, neutral words, and emotional words）. A gradient echo T2＊weighted sequence was used for the functional scans. Statistical maps were constructed using the general linear model. RESULTS： To emotional auditory stimuli, IBS patients relative to controls responded with stronger deactivations in a greater variety of emotional processing regions, while the response patterns, unlike in controls, did not differentiate between distressing or pleasant sounds. To neutral auditory stimuli, by contrast, only IBS patients responded with large significant activations. CONCLUSION： Altered cerebral response patterns to auditory stimuli in emotional stimulus-processing regions suggest that altered sensory processing in IBS may not be specific for visceral sensation, but might reflect generalized changes in emotional sensitivity and affectire reactivity, possibly associated with the psychological comorbidity often found in IBS patients.

Effect of acoustic stimuli in patients with disorders of consciousness: a quantitative electroencephalography study

Auditory stimuli are proposed as beneficial neurorehabilitation methods in patients with disorders of consciousness. However, precise and accurate quantitative indices to estimate their potential effect remain scarce. Fourteen patients were recruited from the Neuro-Rehabilitation Unit of Hangzhou Hospital of Zhejiang Armed Police Corps of China. Altogether, there were seven cases of unresponsive wakefulness syndrome（five males and two females, aged 45.7 ± 16.8 years） and seven cases of minimally conscious state（six males and one female, aged 42.3 ± 20.8 years）. Simultaneously, fourteen healthy controls（10 males and 4 females, aged 51.7 ± 9.7 years） also participated in this case-control experiment. Brain response to music, subjects＇ own name, and noise was monitored by quantitative electroencephalography（QEEG） in the resting state and with acoustic stimulation. Predictive QEEG values in various brain regions were investigated. Our results show that cerebral activation was high in subjects stimulated by their own name, especially in the temporal lobe in patients with disorders of consciousness, and the frontal lobe in the control group. Further, during resting and stimulation, QEEG index（δ ＋ θ/α ＋ β ratio） negatively correlated with the Coma Recovery Scale-Revised score in traumatic disorders of consciousness patients. Hence, we speculate that a subject＇s own name might be an effective awakening therapy for patients with disorders of consciousness. Moreover, QEEG index in specific stimulation states may be used as a prognostic indicator for disorders of consciousness patients（sensitivity, 75%; specificity, 50%）.

Temporal sequential correlation analysis on compoundaction potentials of the auditory nerve versus the stimulating AM-sound envelope

Compound action potentials of the auditory nerve in response to amplitude modulating tones were recorded in guinea pigs with electrode implanted to the exit of the internal auditory meatus and temporal sequential correlation between the responses and the modulators was studied in a paradigm of systematically changing acoustic parameters. Three kinds of modulators were used. continuous or burst sinusoids of fixed frequency (in the range of 40 Hz-5 kHz), short bursts of sinusoids with changing frequency and short segments of speech signal. Ranges of parametric variation were 500 Hz-20 kHz for carrier frequency, 5%-95% for modulation depth and 20 dB-90 dB SPL for intensity. For continuous or burst sinusoidal modulators of fixed frequencies, the correlation coefficient (r) remained quite high in most parametric conditions, ranging from 0.80 to 0.95. It became smaller mainly in instances of decreased response amplitude on account of unfavourable parameters. For burst modulators of changing frequency, r varied around 0.66-0.86. When segments of speech signal served as the modulators, significant correlation (r around 0.50 ) also existed, indicating the validity of the timing mode of information encoding for speech sound at the cochlear nerve level. Some theoretical and technical points in studying the timing mechanism of audition is discussed.

Multi-mechanical waves against Alzheimer’s disease pathology:a systematic review

Alzheimer’s disease(AD)is the most common cause of dementia,afecting approximately 40 million people worldwide.The inefectiveness of the available pharmacological treatments against AD has fostered researchers to focus on alternative strategies to overcome this challenge.Mechanical vibrations delivered in diferent stimulation modes have been associated with marked improvements in cognitive and physical performance in both demented and nondemented elderly.Some of the mechanical-based stimulation modalities in eforts are earlier whole-body vibration,transcranial ultrasound stimulation with microbubble injection,and more recently,auditory stimulation.However,there is a huge variety of treatment specifcations,and in many cases,conficting results are reported.In this review,a search on Scopus,PubMed,and Web of Science databases was performed,resulting in 37 papers.These studies suggest that mechanical vibrations delivered through diferent stimulation modes are efective in attenuating many parameters of AD pathology including functional connectivity and neuronal circuit integrity defcits in the brains of AD patients,as well as in subjects with cognitive decline and non-demented older adults.Despite the evolving preclinical and clinical evidence on these therapeutic modalities,their translation into clinical practice is not consolidated yet.Thus,this comprehensive and critical systematic review aims to address the most important gaps in the reviewed protocols and propose optimal regimens for future clinical application.