Amitava Biswas

Mechanically evoked perioral reflexes in premature and term human infants

Neurophysiological assessment of the preterm human neonatal oromotor system has been limited due to their fragile medical state, and methodological limitations. A new, noninvasive technology known as the actifier was developed and used to evoke perioral motor unit activity during non-nutritive suck in preterm infants. A significant ontologic trend for the early component of the perioral reflex (R1) was discovered in the context of spontaneous, centrally-patterned oromotor behavior.

Expert System-Type Approach to Voice Disorders: Scheduling Botulinum Toxin Treatment for Adductor Spasmodic Dysphonia

One of the most debilitating disorders is adductor spasmodic dysphonia (ADSD), a voice disorder caused by involuntary movements of the muscles of the larynx (voice box). For treating ADSD, botulinum toxin (BT) injections turned out to be very useful. However, the effects of BT are highly variable, so at present, there is no objective criterion of when such a BT treatment is necessary. It is therefore desirable to develop such a criterion. In this paper, we show that traditional statistical techniques are unable to generate such a criterion, while a natural expert system approach seems to be capable of generating reasonably simple rules that determine when a BT treatment is necessary.

Optimal interstimulus interval for auditory discrimination of intensity, duration, and frequency for normal adults

Ten normal‐hearing college students performed two‐interval, two‐alternative, forced choice discrimination tasks designed to determine the optimal range of interstimulus (ISI) intervals for auditory discrimination of intensity, duration, and frequency. Stimuli were randomized (roved) along frequency, intensity, and duration dimensions to reduce monotony and minimize the listener’s reliance on a remembered standard. The center frequency was 500 Hz, the center duration was 30 ms, and the center intensity was 75 dB SPL. Differences to be discriminated were from 0.75 to 3.0 dB for intensity, 1.5 to 6 ms for duration, and 7 to 20 Hz for frequency. Interstimulus intervals were studied from 70 ms to 15 s. Maximum discrimination scores were observed in the range of ISIs from 1.0 to 3.0 s, for all three stimulus dimensions. These preliminary findings suggest the operation of a common, dimension‐independent, sensory processing mechanism within the central nervous system. [Work supported by NIH and Neuro Logic, Inc.]

Exploring some questions on occlusion or the Bing effect during speech production with a microphone coupled to the speaker's external ear canal

Sometimes some speakers prefer to use their palm or other objects to cover or occlude at least one ear during public address. This practice may be helpful to enhance their self monitoring of the sound production using the occlusion effect. The basic occlusion effect in the human auditory system has been explored and reported in the literature by several individuals. According to those reports, the speaker can hear his or her own voice significantly louder when the ear canal is blocked at the outer end. Many clinicians routinely utilize detectability of vibrations from a tuning fork when placed on the mastoid process and the ear canal is occluded. This is popularly known as the Bing effect. These empirical data suggest existence of an efficient acoustic connectivity from the vocal tract to the ear canal for healthy individuals. Therefore, this study will explore quantified effects of the classic Bing effect for several speakers across the audio spectrum with a microphone coupled to the speakers external ear canal.Sometimes some speakers prefer to use their palm or other objects to cover or occlude at least one ear during public address. This practice may be helpful to enhance their self monitoring of the sound production using the occlusion effect. The basic occlusion effect in the human auditory system has been explored and reported in the literature by several individuals. According to those reports, the speaker can hear his or her own voice significantly louder when the ear canal is blocked at the outer end. Many clinicians routinely utilize detectability of vibrations from a tuning fork when placed on the mastoid process and the ear canal is occluded. This is popularly known as the Bing effect. These empirical data suggest existence of an efficient acoustic connectivity from the vocal tract to the ear canal for healthy individuals. Therefore, this study will explore quantified effects of the classic Bing effect for several speakers across the audio spectrum with a microphone coupled to the speakers external e...

Alternative methods for faster and more accurate estimation of hearing threshold

Determination of audiologic threshold is often necessary for variety of diagnoses and treatments. The usual method involves “10 dB down for response and 5 dB up for miss”. This common procedure lacks sufficient accuracy to identify smaller changes due to temporary threshold shift and for early diagnosis of degradation of hearing threshold due to ototoxicity or chemotherapy etc. This presentation will explore several alternative methods for faster and more accurate estimation of the threshold.

Development of a simple replica of the middle ear pathology for demonstration of tympanometric measurements

This study evaluates a simple replica of the middle ear pathology for demonstration of tympanometric measurements. Common tympanometers often use small passive cavities for calibration of basic measurements such as equivalent ear canal volume. But the real ear normally presents an inverted V shaped tympanogram. The pathologic ears present various characteristic shapes of tympanograms such as unusually high or low peaks. In some patients the tympanometric peak may be shifted away from the zero differential pressure point. Often such patients may not be readily available during a classroom demonstration of the procedures. Utility of this study to replicate such pathologic conditions with a simple model will be discussed.

Exploring some questions on occlusion effect in the human auditory system when a musician or singer's external ear canal is blocked

Sometimes some musicians and singers prefer to use their palm or other objects to cover or occlude at least one ear during performance. This practice may be helpful to enhance their self monitoring of the sound production using the occlusion effect. The basic occlusion effect in the human auditory system has been explored and reported in the literature by several individuals. According to those reports, the musician or singer can hear his or her own voice or musical instrument significantly louder when the ear canal is blocked at the outer end. Many clinicians routinely utilize detectability of vibrations from a tuning fork when placed on the mastoid process and the ear canal is occluded. This is popularly known as the Bing effect. These empirical data suggest existence of an efficient acoustic connectivity from the vocal tract to the ear canal for healthy individuals. Therefore, this study will explore quantified effects of the classic Bing effect for normal healthy musicians and singers across the audio...

Assessment of acoustic characteristics of the nasal cavity by measuring sound transmission from one nostril to the other by a small speaker and a microphone

Sometimes clinicians need to assess aerodynamic and acoustic characteristics of the nasal cavity. Some patients with cranio-facial anomalies such as cleft palates may need such assessments. Certain disease specific pathologies may involve temporary blockage in the nasal cavity. This study will present a simple procedure of computing the transfer function of acoustic energy from one nostril to the other.

Assessment of granular distortion in digital sound recorders by statistical analyses of recorded sound and analytically distinguishing quality of 24-bit and 16-bit analog to digital converters

Modern sound recording systems are mostly digital type, using at least one or several analog to digital converters that commonly provide 24-bit or 16-bit resolution and accordingly limits the recording quality. The use of such digitizers inherently add some granulation distortion. A 16 bit digitizer is theoretically limited to granulation step size of 1/65,536. Whereas a 24 bit digitizer is theoretically limited to granulation step size of 1/16,777,216. Smaller granulation step size provides better fidelity of the recording. This study explored the operational resolution of a few of such digital recorders by statistical analysis of samples of recorded sound tracks. The histogram of the digital samples of the sound recordings showed that a digitizer may not always be digitizing to the finest precision.

An investigation of passive type hearing protection in human and animals by their auricles by diverting natural drainage of rain water along facial features into the ear canal

Many textbooks in human auditory system begins with the external ear and basically describe the auricle as a collector of sound. In this study, we have explored the utility of the auricle to protect the external ear canal from environmental factors such as rain shower or sand storm. A model of human head of typical dimensions was held in upright position inside a bath tub. A shower head was positioned directly above the model head. One ear of the model was sliced off. Each ear canal was provided internally a tube of about 8 mm diameter connected to a collecting bottle of about 500 cc capacity. The shower head output was about eight liters of water per minute. The results suggest that the impaired ear is more vulnerable to water entry compared to the unimpaired ear of the model. Therefore, another vital necessity of evolution of the external ear may have been environmental protection, in addition to collection of sound energy. Generalization of the data for other common animals will be discussed.