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Biomedical subjects

Juen-Haur Hwang

Publications and source records attributed to Juen-Haur Hwang.

10 recordsLinked to original sources
PubMed2006

The effects of masking on the activation of auditory-associated cortex during speech listening in white noise.

CONCLUSIONS: Noise-induced masking has different effects on the two hemispheres during speech listening. Auditory-associated cortices in the left hemisphere were more affected by masking than the right side. However, activation of primary and secondary auditory cortices was not affected in both sides under the masking with high signal to noise ratio. OBJECTIVES: The purpose of this study was to investigate the effects of masking on the central auditory system during speech listening in white noise. MATERIALS AND METHODS: Twelve healthy young subjects with normal hearing participated in this study. Functional magnetic resonance imaging (fMRI) was performed while subjects were listening to speech sounds alone and speech plus white noise binaurally. RESULTS: In humans, the activation of several regions including the middle parts of the superior and middle temporal gyri, parahippocampal gyrus, cuneus and thalamus of the left hemisphere was significantly reduced under the masking paradigm with +5 dB signal to noise ratio. In addition, reduced activation was also found at the lingual gyrus, anterior and middle parts of the superior temporal gyrus (STG), uncus, fusiform gyrus, and inferior frontal gyrus of the right hemisphere during masking.

Acoustic Stimulation↗
PubMed2006

Changes in activation of the auditory cortex following long-term amplification: an fMRI study.

CONCLUSION: Speech-elicited activation decreased after monaural amplification bilaterally during unaided or aided ear stimulation, but tended to recover later at the contralateral hemisphere during aided ear stimulation. OBJECTIVES: The purpose of this study was to investigate the changes in the activation pattern of auditory cortex following long-term monoaural amplification. PATIENTS AND METHODS: Serial functional magnetic resonance images were obtained while speech sounds were presented to the aided (right) and unaided (left) ears of eight hearing-impaired subjects before, 3 months, and 9 months after beginning the use of a single hearing aid. The results were analyzed by group analysis. RESULTS: Before hearing aid fitting, we found that activation patterns of the auditory cortex were somewhat segmented in the left hemisphere, regardless of whether the speech sounds were delivered to right or left ear. Cross projection was lost in response to right ear stimulation. After hearing aid fitting, on the unaided side stimulation, the activation tended to decrease progressively on both sides 3 months and 9 months after beginning monoaural amplification. On the aided side stimulation, activation also decreased 3 months after amplification bilaterally, but tended to recover at the contralateral hemisphere after 9 months of amplification. Cross projection was restored in response to right ear stimulation.

Acoustic Stimulation↗
PubMed2005

Hemispheric difference in activation patterns of human auditory-associated cortex: an FMRI study.

The purpose of this study was to demonstrate interhemispheric differences in activation patterns of the auditory-associated cortex elicited by a series of sounds. Functional magnetic resonance imaging was performed while different sounds were presented binaurally to 10 healthy subjects with normal hearing. Characteristic activation patterns were elicited although variability was shown between subjects. The activation number was significantly higher on the right than on the left side for non-speech (but not for speech) stimulations. As stimulation increased in complexity (from a pure tone to white noise to ocean wave sounds to classical music), the activation pattern of the superior temporal lobe became more pronounced in both hemispheres while that of the auditory cortex tended to become more sustained and concentrated on the right rather than on the left side. No hemispheric differences in activation pattern were seen in response to speech.

Acoustic Stimulation↗
PubMed2005

Paradoxical vocal cord motion--a case report.

Paradoxical vocal cord motion (PVCM) is an unusual cause of stridor, which is associated with some underlying causes, such as central nervous system lesion, gastroesophageal reflux or psychogenic problem. Once a diagnosis of PVCM is made, acute management with reassurance and sedation instead of aggressive airway intervention is required. Speech therapy, psychotherapy combination with anti-reflux medication is considered to be useful in long-term management. We present a 58 year-old male patient who had suffered from several episodes of acute onset of stridor, short of breath and tachypnea since one year ago. He was initially treated as an asthmatic patient with poor response. Aneurysm of ascending aorta by angiography, and mild gastroesophageal reflux with hiatal hernia by panendoscopy were noted. Then, the paradoxical vocal cord motion during inspiration phase was confirmed by flexible fiberoptic nasopharyngoscope after the consultation with an otolaryngologist. The emergency of his air-hunger was relieved quickly after psychological intervention. Now, he is free of stridor attack under anti-reflux therapy and psychotherapy.

Botulinum Toxins↗
PubMed2005

Potassium-titanyl-phosphate laser nasopharyngectomy with nasopharyngoscopic guidance for recurrent nasopharyngeal carcinoma.

Management of recurrent nasopharyngeal carcinoma is a challenge to head and neck surgeons. Traditional methods of nasopharyngectomy for the treatment of recurrent nasopharyngeal carcinoma carry considerable complications. This report describes the technique of potassium-titanyl-phosphate (KTP) laser nasopharyngectomy under nasopharyngoscopic guidance. This technique allows access to the nasopharynx without damaging structures in the facial region. It results in minimal blood loss, and requires no nasal packing. We report the use of this technique to treat 6 patients with recurrent nasopharyngeal carcinoma. All patients were able to resume their oral diet 8 hours after recovery from general anesthesia, and were discharged within 2 days. Our results suggest that this technique is useful for excising locally recurring nasopharyngeal carcinomas. Prospective trial of this technique with long-term follow-up is necessary to determine its effectiveness and safety.

Adult↗
PubMed2004

Effects of alcohol and noise on temporary threshold shift in Guinea pigs.

The purpose of this study was to investigate the effects of concomitant exposure to noise and alcohol on the auditory thresholds. Twenty-four guinea pigs were equally divided into three groups: the acute intoxication group, the chronic intoxication group and the control group. Animals in the acute group received single intraperitoneal injections of ethanol (2 g/kg). In the chronic group, alcohol was administered via drinking water (10%, v/v) over a 60-day period. All animals were exposed to a white noise at the intensity of 105 dB A for 30 min. Auditory brainstem response (ABR) thresholds and distortion product otoacoustic emission (DPOAE) levels were measured before, immediately after noise exposure and also 1, 2, and 7 days following exposure. The results showed: first, acute alcohol injection caused a significant, temporary elevation of ABR threshold (4.8 dB in average), while chronic alcohol treatment did not change auditory threshold significantly. Second, noise exposure induced a mean threshold shift of 15.4- 19.7 dB. ABR threshold returned to normal 2 days after exposure. Both acute and chronic alcohol treatment did not alter the magnitude and time course of recovery of the temporary threshold shift (TTS). Third, the mean DPOAE amplitudes decreased at most frequencies following acute injection of alcohol. However, the differences did not reach statistical significance. Fourth, the mean DPOAE levels dropped 3.4-9.6 dB in all groups after noise exposure and returned to normal 1 day to 2 days after noise. There were no significant differences in the amount of DPOAE suppression after noise between the three groups. In summary, we have found that acute and chronic treatment of alcohol in combination with noise did not significantly exacerbate TTS or decrease DPOAE amplitudes relative to noise exposure alone.

Alcoholic Intoxication↗
PubMed2003

Acute effects of alcohol on auditory thresholds and distortion product otoacoustic emissions in humans.

OBJECTIVE: To investigate the acute effects of alcohol consumption on pure-tone thresholds (PTs) and distortion product otoacoustic emissions (DPOAEs) in humans MATERIAL AND METHODS: Eight healthy adults were asked to drink alcohol to the clinical intoxication level. PTs and DPOAEs were determined serially before and after alcohol ingestion. RESULTS: Alcohol had no effect on PTs DPOAE amplitudes above 5500 Hz dropped 30 min and 1 h after alcohol ingestion, returning to the pre-test level 2 h after ingestion. CONCLUSION: In humans, acute alcohol consumption to the intoxication level may cause a temporary reduction in DPOAE amplitudes at high frequencies without affecting auditory thresholds.

Adult↗
PubMed2002

Community-acquired methicillin-resistant Staphylococcus aureus infections in discharging ears.

OBJECTIVES: Although community-acquired methicillin-resistant Staphylococcus aureus (MRSA) infections have recently become an increasing problem in various fields of medicine, they have rarely been studied in the ear. The purpose of this study was to determine the prevalence of community-acquired MRSA infections in discharging ears and to compare the epidemiology of MRSA with that of other pathogens. MATERIAL AND METHODS: Between August 2000 and February 2002, 248 isolates recovered from 221 discharging ears of patients with 3 disease entities (chronic otitis media, acute otitis externa and granular myringitis) were prospectively analyzed using bacteriology. The isolates analyzed using bacteriology were divided into three groups: MRSA, methicillin-susceptible S. aureus (MSSA) and non-SA. RESULTS: S. aureus was found in 108 (43.5%) isolates and MRSA in 27. Therefore, the percentage of MRSA among the S. aureus isolates was 25.0% (27/108). The prevalence of community-acquired MRSA infections in discharging ears was 12.2% (27/221) and the MRSA strains were highly susceptible to vancomycin, teicoplanin, fusidic acid and minocycline. The MRSA-infected patients were older than those infected with other groups of pathogens. Also, MRSA infections appeared to be more common in chronic otitis media than in acute otitis externa or granular myringitis. CONCLUSIONS: Community-acquired MRSA represents an increasing problem. In this study, MRSA strains were highly susceptible to vancomycin, teicoplanin, fusidic acid and minocycline.

Acute Disease↗
PubMed2002

Changes in bacteriology of discharging ears.

A bacteriological study on 161 consecutive out-patients presenting with otorrhoea was performed prospectively at a local teaching hospital in Taiwan between August 2000 and June 2001. A total of 177 isolates were recovered. Staphylococcus aureus was found in 77 (43.5 per cent) isolates, and non-Staphylococcus aureus in 100 (56.5 per cent) isolates. Pseudomas sp was found to be the most common pathogen (28.8 per cent) in the non-Staphylococcus aureus group. Staphylococcus aureus had become more common than Pseudomonas aeruginosa in acute otitis externa, granular myringitis, and chronic otitis media in Taiwan. Methicillin-resistant Staphylococcus aureus (MRSA) was also an increasing problem in all three disease entities. The prevalence of community-acquired MRSA infections in discharging ears was found to be 13.7 per cent (22/161). MRSAs were highly susceptible to vancomycin, teicoplanin, fusidic acid, and minocycline. More studies should be done to determine the susceptibility of MRSA to ofloxacin in the future.

Acute Disease↗