Cerebellum connects with each part of the auditory pathway directly or indirectly, forming the anatomical basis for a cerebellar role in auditory process. Functional imaging studies and clinical observations provide more abundant support for this view. Tinnitus is one of the most common clinical manifestations when the auditory system is impaired and remains unsolved. Basic science researches in neurotransmitter chemistry and molecular biochemistry, together with functional imaging studies, indicate that cerebellum might contribute to the pathophysiology of tinnitus. In this review we summarize the current understanding of cerebellar role in auditory process and tinnitus.
Auditory Pathways ; Cerebellum ; physiopathology ; Humans ; Tinnitus ; physiopathology

In addition to aberrant features in the speech, children with Autism Spectrum Disorder (ASD) may present unusual responses to sensory stimuli, especially to auditory stimuli. We investigated the auditory ability of children with ASD by using Auditory Brainstem Responses (ABR) as they can directly judge both hearing status and the integrity of auditory brainstem pathways. One hundred twenty-one children (71: ASD; M 58/ F 13, mean age; 41.8 months, 50: control group; M 41/ F 9, mean age; 38 months) were induded in the study. As compared with the values in the control group, the latency of wave V, wave I-V, and wave III-V inter-peak latencies were significantly prolonged (p<0.05) in the ASD group. The findings indicate that children with ASD have a dysfunction or immaturity of the central auditory nervous system. We suggest any children with prolonged III-V inter-peak latencies, especially high functioning children should be further evaluated for central auditory processing to set up a more appropriate treatment plan.
Analysis of Variance ; Auditory Pathways/physiopathology ; Autistic Disorder/*physiopathology ; Child, Preschool ; Electrophysiology ; Evoked Potentials, Auditory, Brain Stem/*physiology ; Female ; Humans ; Male

OBJECTIVE: To investigate the relationship between pure-tone average (PTA), the fractional anisotropy (FA) of the auditory pathway, cognitive cortex and auditory cortex in presbycusis. METHOD: Twenty-five elderly subjects with presbycusis were participated in the study. PTA, speech discrimination abilities were evaluated in each subject. Diffusion tensor imaging (DTI) was applied to access the FA of the IC, the superior frontal gyrus and the Heschl's gyrus. Compare the difference between two sides of the values of FA in the three areas. Bivariate correlation analysis was performed to evaluate the effects of PTA and FA of the inferior colliculus (IC), the superior frontal gyrus and the Heschl's gyrus on speech discrimination abilities. RESULT: There were no significant differences between the left and right side of the inferior colliculus (P > 0.05). Higher FA values were recorded at the left side of the Heschl's gyrus and the superior frontal gyrus (P < 0.05). Both PTA and the FA of the superior frontal gyrus have a negative association with speech discrimination abilities (P < 0.01, P < 0.05), while the FA of the Heschl's gyrus has a positive association with speech discrimination abilities (P < 0.05). CONCLUSION Our findings indicated that the speech discrimination abilities of the elderly is not only related to the peripheral auditory function, but also to the central auditory and cognitive function.
Aged ; Audiometry, Pure-Tone ; Auditory Cortex ; physiopathology ; Auditory Pathways ; Diffusion Tensor Imaging ; Humans ; Inferior Colliculi ; physiopathology ; Presbycusis ; diagnosis ; Speech Perception

Background: Tinnitus is a common disorder that causes significant morbidity; however, the neurophysiological mechanism is not yet fully understood. A relationship between tinnitus and limbic system has been reported. As a significant component of the limbic system, the hippocampus plays an important role in various pathological processes, such as emotional disturbance, decreased learning ability, and deterioration of memory. This study was aimed to explore the role of the hippocampus in the generation of tinnitus by electrophysiological technology. Methods: A tinnitus model was established in rats through intraperitoneal injection of salicylate (SA). Subsequently, the spontaneous firing rate (SFR) of neurons in the hippocampal CA1 area was recorded with in vivo multichannel recording technology to assess changes in excitability induced by SA. To investigate the effect of excitability changes of hippocampus on the auditory pathway, the hippocampus was electrically stimulated and neural excitability in the auditory cortex (AC) was monitored. Results: Totally 65 neurons in the hippocampal CA1 area were recorded, 45 from the SA group (n = 5), and 20 from the saline group (n = 5). Two hours after treatment, mean SFR of neurons in the hippocampal CA1 area had significantly increased from 3.06 ± 0.36 Hz to 9.18 ± 1.30 Hz in the SA group (t = -4.521, P < 0.05), while no significant difference was observed in the saline group (2.66 ± 0.36 Hz vs. 2.16 ± 0.36 Hz, t = 0.902, P > 0.05). In the AC, 79.3% (157/198) of recorded neurons showed responses to electrical stimulation of the hippocampal CA1 area. Presumed pyramidal neurons were excited, while intermediate neurons were inhibited after electrical stimulation of the hippocampus. Conclusions The study shows that the hippocampus is excited in SA-induced tinnitus, and stimulation of hippocampus could modulate neuronal excitability of the AC. The hippocampus is involved in tinnitus and may also have a regulatory effect on the neural center.
Animals ; Auditory Pathways ; physiopathology ; CA1 Region, Hippocampal ; physiopathology ; China ; Male ; Rats ; Rats, Sprague-Dawley ; Reproducibility of Results ; Tinnitus ; physiopathology

OBJECTIVETo explore the clinic characteristics, audiological characteristics and location of lesions in children with retrocochlear auditory nerve impairment which, including auditory neuropathy characterized by severely abnormal results of ABR and normal results of DPOAE.

METHODSBetween 2002 and 2006, eighty-six cases (165 ears) with severely abnormal ABR but normal results of DPOAE were enrolled in the study group. The mean patient age was one year and one-month-old, with a range of 8 days to 7 years. The cases with abnormal conductive function were excluded. The cases with severely abnormal ABR and normal cochlear functions as measured by DPOAE and without abnormal conductive function were selected as the cochlear lesion group. Some same age healthy children without hearing loss were subjected as normal control group. The latency and amplitude of waves I, III and V, the inter peak latency I-III was compared among the three group.

RESULTS(1) Fifty-one cases (59.3%) had a history of hypercholesterolemia during neonatal period, but 40 cases (46.51%) had a severe hypercholesterolemia and 11 cases (12.79%) had mild or moderate hypercholesterolemia. Clinical features common among the population included a history of dyskinesia [n = 40 (46.51%)], hearing and language disorder [n = 10 (11. 63%)]. Thirty-two cases (37.2%) were accompanied by cerebral palsy . (2) Among the 165 ears, absent ABRs to click stimuli presented at 103 dB was in 103 ears, only wave I was developed in 27 ears and only wave V was developed in 19 ears,wave I and III in 13 ears and differentiated wave I and V in 3 ears. (3) When compared to control group, the latency of wave I was prolonged and amplitude of wave I was lower in cases with only wave I developed (t = -6.75 and 2.58, P < 0.05). For for cases with only wave I and III differentiated, the latency and amplitude of wave I was the same but the latency of wave III was prolonged and amplitude of wave III was lower while interpeak latency I-III was prolonged.

CONCLUSIONSAuditory neuropathy which was characterized by severely abnormal ABR was the most common type of retrocochlear auditory nerve impairment. It was mainly due to a disorder of VIII nerve. The pathologies that affect higher levels of the auditory pathway, from the brainstem to the auditory cortex, might be the main sites of lesion in cases with only wave I developed. Superior olivary nucleus where wave III was generated and higher levels of the auditory pathway might be the main sites of lesion in cases with wave I and III differentiated. The low-amplitude wave V was not characteristics of auditory neuropathy. Cerebral cortex, brain stem auditory nucleus and VIII nerve might be damaged successively in cases with retrocochlear auditory nerve impairment induced by hypercholesterolemia.

Auditory Pathways ; physiopathology ; Case-Control Studies ; Child ; Child, Preschool ; Cochlear Nerve ; pathology ; Evoked Potentials, Auditory, Brain Stem ; Humans ; Infant ; Infant, Newborn ; Retrocochlear Diseases ; pathology ; physiopathology

AIMObserve the effects of er-long-zuo-ci-wan (EIZCW, a compound of Chinese Traditional Medicine) on the spontaneous discharge of external cortex of inferior colliculus (ICx) and secondary auditory cortex (AII) of chronic tinnitus model rats induced by salicylate acid, to explore the neural mechanisms underlying ELZCW preventing tinnitus.

METHODS30 adult SD rats were involved and divided into three groups, normal control group, chronic tinnitus model group and ELZCW prevention group. Extracellular recording techniques and stereotaxic method were used. The spontaneous spikes were recorded and analyzed from ICx and all in different group rats. The average rate of spontaneous discharge and the interspike interval histogram of spontaneous activities were used as indexes.

RESULTS(1) Compared with normal control group, the average rate of spontaneous discharge recorded from the ICx in the chronic tinnitus model group increased significantly (4.57 +/- 0.54 Hz vs. 3.14 +/- 0.40 Hz, P < 0.05). Furthermore analysis showed that the discharge rate of short spike interval from the ICx in the chronic tinnitus model group increased than that of the normal group (0-40 ms: 58% vs. 40%; 0-4 ms: 9% vs. 5%). And there was an increasing tendency of the average rate of spontaneous discharge recorded from the AII in the chronic tinnitus model group compared with that in the normal group. (2) Compared with the chronic tinnitus model group, the average rate of spontaneous discharge recorded from the ICx and AII in the ELZCW prevention group significantly decreased than that in the chronic tinnitus model group (ICx: 2.41 +/- 0.21 Hz vs. 4.57 +/- 0.54 Hz, P < 0.01. AII: 2.24 +/- 0.24 Hz vs. 4.57 +/- 0.54 Hz , P < 0.01). And the discharge rate of short spike interval from the ICx and AII in the chronic tinnitus model group decreased than that in the normal control group (ICx: 0-40 ms 50% vs. 58%, 0-4 ms 4% vs. 9%. All: 0-22 ms: 24% vs. 31%, 0-8 ms 19% vs. 16%).

CONCLUSIONIf the increasing of the spontaneous activities of ICx and AII in chronic tinnitus rats means tinnitus, the use of ELZCW could decrease this kind of changes.

Animals ; Auditory Cortex ; physiopathology ; Auditory Pathways ; drug effects ; physiopathology ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Male ; Phytotherapy ; Rats ; Rats, Sprague-Dawley ; Salicylic Acid ; Tinnitus ; chemically induced ; drug therapy ; physiopathology

The prevalence of auditory neuropathy is not known, although the majority of cases are felt to lie within the population of neonatal intensive care unit graduates. We report three cases of auditory neuropathy, out of 211 children with sensorineural hearing loss, seen at our audiology clinic from April 1, 1999 to December 31, 2003. Two patients did not have a risk factor for hearing impairment. Screening policies based solely on transient evoked otoacoustic emissions testing will not detect auditory neuropathy effectively, and may falsely reassure parents and professionals unaware of this condition.
Auditory Pathways ; physiopathology ; Child ; Child, Preschool ; Cochlear Nerve ; physiopathology ; Hearing Disorders ; diagnosis ; Hearing Loss, Sensorineural ; diagnosis ; etiology ; Hearing Tests ; Humans ; Male ; Otoacoustic Emissions, Spontaneous ; Prevalence ; Risk Factors

OBJECTIVE: To investigate the intra-operative electrical evoked auditory brain stem response (EABR) characteristics and the hearing and speech rehabilitation effects of cochlear implantation (CI) in patients with internal auditory canal stenosis (IACS). METHOD: A retrospective study was performed on 16 patients with IACS (IACS group) matched with 16 implanted without IACS (control group), who received multi- channel CI because of pre-lingual sensorineural hearing loss. The integrity and functional status of the auditory pathway were assessed by EABR, recording waveforms, thresholds and dynamic ranges intra-operation before CI. Interviewed the implanted parents or teachers, asking them to rate the implanted hearing and speech ability according to Categories of Auditory Performance (CAP) and Speech Intelligibility Rating (SIR). Paired T test was performed to compare scores of CAP and SIR between before and 1 year after CI, while Spearman test was performed to compare correlation between EABR grades and post-operative CAP scores. RESULT: Among the IACS group, 2 cases weren't recorded typical EABR waveforms and without auditory response 1 year after a successful CI. The EABR waveforms in the IACS group were poorer than that in the control group, their EABR thresholds higher than the control group, and their EABR dynamic ranges less than the control group. The hearing and speech rehabilitation after CI showed that the results of CAP and SIR values (3.47 +/- 1.09 and 1.62 +/- 0.50) scored significantly lower than the control group (5.06 +/- 0.79 and 2.59 +/- 0.58) (P < 0.05), but significantly increased compared with pre-operation. Intra-operative EABR grades and post-operative CAP scores showed significant correlation (r = 0.78 , P < 0.05). CONCLUSION Intra-operative EABR can accurately monitor the integrity and functional status of the auditory pathway, be of important clinical value in predicting whether patients can acquire auditory responses with the aid of CI. CI can help patients with IACS to improve the ability of hearing and speech with EABR to screen out compatible implanted.
Adolescent ; Auditory Pathways ; Child ; Child, Preschool ; Cochlear Implantation ; Constriction, Pathologic ; Ear, Inner ; surgery ; Evoked Potentials, Auditory, Brain Stem ; Female ; Humans ; Infant ; Labyrinth Diseases ; physiopathology ; surgery ; Male ; Retrospective Studies ; Treatment Outcome ; Young Adult