Click Frequency Research Articles

Functional impairment in TMJ patient and nonpatient groups according to a disability index and symptom profile.

AbstractSymptom prevalence figures tend to exaggerate the problem of TMJ disorders. An index based on disability was constructed as an improved measure, consolidating symptom intensity, frequency, and functional impairment.Thereby 80% of TMJ patients were experiencing significant disability. This figure reaffirms the need for better recognition in treatment support for these patients.According to the index, 8% to 10% of a nonpatient group had equivalent severity, but this was weighted by the frequency of TMJ clicking, while accompanying pain and interference were infrequent. TMJ clicking without pain or symptom progression is probably not a strong indication of need for treatment.Sixty-five percent of the patients, compared to only 5% in the control population, reported specific disturbance of jaw function. Women in both groups reported significantly more severe symptoms.Importantly, all indices suffer from not being diagnosis-specific. The benefits of an alternative symptom profile are proposed and discu...

Brainstem auditory evoked responses in the newborn lamb. Studies during postnatal development and acute hypoxia.

Brainstem auditory evoked responses (BAER) have been studied in several species and have provided a neurophysiologic 'window' into brainstem function. We have pursued further studies in the newborn lamb and adult sheep. BAER amplitude increased as the stimulus intensity increased from 45 to 95 dB and as the click frequency decreased from 88.8 to 22.2 Hz. BAER latency increased as both the stimulus intensity decreased and the click frequency increased. Developmental studies were performed between the 2nd and 35th day of life in the newborn lamb. No significant change in either latency, amplitude, or wave morphology was noted in contrast to other species where developmental changes are prominent. This was due to both the prenatal maturation of the lamb's brain and to the relatively short interval of the postnatal studies. We also studied the effect of prolonged severe hypoxia and acidosis on the BAER in the newborn lamb and found no significant change in either the amplitude or latency of the response.

Neurons sensitive to narrow ranges of repetitive acoustic transients in the medial geniculate body of the cat.

Neuronal activity was recorded in the medial geniculate body (MGB) of nitrous oxide anaesthetized, paralysed cats in response to click trains. For most cells responding to these stimuli the spike discharges are precisely time locked to individual clicks within the train. The present study has revealed that, apart from the normal "locker" response being characterized by a monotonic decrease in the entrainment as the frequency of the clicks within the train increases, there is a small population of "lockers" which show a non-monotonic response to increasing click frequency. 41% of these non-monotonic cells were not at all entrained by the lowest click rates and had time-locked responses for very restricted frequency ranges. These particular non-monotonic "lockers" were more commonly-found in the posterior part of the pars lateralis and in the suprageniculate nucleus. These cells might be involved in the temporal coding of natural sounds such as animal vocalizations and the cat's purr.

GENERALIZATION PEAK SHIFT IN RATS UNDER CONDITIONS OF POSITIVE REINFORCEMENT AND AVOIDANCE

Rats were trained to discriminate between two click frequencies. One frequency was associated with either variable-interval food reinforcement (Experiment 1) or free-operant avoidance (Experiment 2). The other frequency was associated with the absence of food in Experiment 1 and the absence of shock in Experiment 2. On a click frequency generalization test, the rats in both experiments showed positive peak shift with the shape of the relative gradients being very similar. This is the first reported instance of peak shift in rats when responding was maintained by an avoidance contingency. Nondifferentially trained controls showed that this shift was due exclusively to associative processes, with nonassociative stimulus factors in themselves apparently making no contribution to increased rates at particular stimulus values. These results show the comparability of appetitive and aversive control and support the position that gradient differences do not result from approach versus avoidance per se.

Earspeaker coupling effects on auditory action potential and brainstem responses.

Human auditory nerve action potential and brainstem evoked response input-output functions were obtained with standard audiometric earspeakers coupled in three different ways, commonly used in auditory evoked potential laboratories (ie, free field, circumaural cushions, standard audiometric cushions). All other stimulus values were matched as closely as possible. Under the different coupling conditoins, substantially different amplitude-intensity and latency-intensity functions were generated for both auditory nerve N1 and brainstem V peaks. Differences among the input-output functions were predictable from differences in click frequency spectra.

A functional measure of brain activity: Brain stem transmission time

Surface-recorded auditory nerve and brain stem responses are being used routinely for diagnostic purposes in man. When interest is in auditory diagnosis, the electric response threshold is of primary importance. However, when used in neurological diagnosis, the wave form of the response is important. As a measure of one aspect of response wave form, this paper suggests the use of brain stem transmission time (BTT), defined as the time interval between the first earlobe-negative wave (response of the auditory nerve — the ‘input’ to the brain stem) and the earlobe-positive wave from the region of the inferior colliculus (the ‘output’ of the brain stem). The paper shows that BTT is longest in neonates, approaches adult values at the age of about 3 years, is relatively independent of click intensity, conductive hearing loss (middle ear lesion), click rate (except for high rates) and click frequency (filtered clicks). The finding that in a given age group, BTT is generally independent of most stimulus conditions, makes it a useful functional test of brain stem activity.

Normal short-latency electrophysiological filtered click responses recorded from vertex and external auditory meatus

We recorded normal electrophysiological responses to third-octave filtered clicks from external auditory meatus (EAM) and vertex electrodes referred to coupled earlobe electrodes (forehead ground). From both vertex and EAM, polarity-sensitive responses predominated at low frequencies and exhibited characteristics of both phase-locked neural responses (frequency-following response or FFR) and cochlear microphonics (CM). The FFR-like response predominated at the vertex site and the CM-like response predominated at EAM. At high frequencies, polarity-insensitive responses closely resembled rectangular-pulse click action potentials and brainstem evoked potentials, with clearly defined N1 and V peaks recorded from EAM and vertex, respectively. As frequency was lowered, the N1 and V peak latencies increased, the peaks broadened, and the latency-intensity curves steepened with greater prolongation occurring at lower click intensities. Lowering click frequency also shortened the N1-V interval and caused the plot of N1-V interval versus click intensity to become steeper. Plots of polarity-insensitive response amplitudes and thresholds against frequency revealed a high frequency bias for both N1 and V, but the V "frequency response" was flatter. A possible explanation of the shortened N1-V interval at low click frequencies based on this flatter V "Frequency response" is presented.

On the frequency of early systolic clicks in mitral valve prolapse.

Phonocardiography was performed in 74 patients with mitral valve prolapse. 24 patients had early systolic clicks (less than 80 msec from S1). Four of them had associated systolic murmurs. 30 patients had mid or late systolic clicks (greater than 80 msec from S1). A systolic murmur followed the click in 13 of these patients. Both an early and mid/late systolic click were noted in three patients. 17 patients did not have systolic murmurs. Seven patients had 'silent' mitral valve prolapse. In summary, early systolic clicks are common in mitral valve prolapse. In many instances the early click is not accompanied by a murmur. Echocardiography is recommended in patients with chest pain or arrhythmia of uncertain etiology, even if characteristic signs of mitral valve prolapse are absent.

Some tests of the additivity (autoshaping) theory of behavioral contrast.

Two experiments were performed to determine whether the location of the discriminative stimuli affects the amount of positive behavioral contrast exhibited during discrimination learning by pigeons. When signals for reinforcement and nonreinforcement of keypecking were situated directly on the response key (different line tilts), pecking rates during the positive stimulus were higher than when the source of the signals was located elsewhere (changes in chamber illumination or auditory click frequency). These results are in general agreement with the additivity theory of behavioral contrast, which attributes contrast to the combined effects of stimulus-reinforcer and response-reinforcer correlations on behavior directed at signals of reinforcement. Some shortcomings of the theory were discussed, and the notion that behavioral contrast is a basic, unitary phenomenon was criticized.

Human whole-nerve response to clicks of various frequency.

The averaged VIIIth nerve response to third-octave clicks at 500, 2000 and 8000 Hz was recorded from the promontory of 4 normal-hearing young adults. As click frequency is lowered, the N, latency increases in a manner consistent with the changes in velocity of the cochlear traveling wave. This finding suggests that clicks of different spectral content stimulate different regions of the basilar membrane. N amplitude shows a general increase with frequency; this observation appears related to the increased synchrony of neural firing that results from the higher velocity of the traveling wave in the more basal portions of the cochlea.

Behavioral contrast in pigeons learning an auditory discrimination

After an initial period of nondifferential training, 14 pigeons were trained on a go/no-go discrimination between different click frequencies. Keypeck responses during the positive stimulus were reinforced with food on a 1-min variable interval schedule, whereas responses during the negative stimulus were extinguished and prolonged the negative stimulus for 30 sec (correction procedure). Response rates in the positive stimulus increased during discrimination training in all subjects. A control group given extended nondifferential training had significantly lower response rates and contrast ratios. The results are inconsistent with a simple autoshaping theory of behavioral contrast.

Stimulus generalization and discrimination along the click-frequency (flutter) continuum in pigeons

Before tests for click-frequency generalization, pigeons had been reinforced for keypecks during one click frequency (S+). Some Ss received S+ training only, whereas other Ss also received unreinforced (S−) trials, during which the clicks were either absent (Experiments 1-3) or presented at some other frequency (faster or slower than S+: Experiment 4). When training included S+ trials only, birds responded approximately equally to all generalization test frequencies (0.0 to 53.5 pulses/sec, pps). Most Ss that had received both S+ and S− training trials responded fastest not during S+ but during click frequencies even further away from S− along the click-frequency dimension (peak shift). Complex bimodal gradients were obtained after training with S+ (1.6 pps) vs S− (0.0 pps); maximal responding generally occurred near S+ and at approximately 14.2 pps. Among other factors, the “nonorthogonality” of click absence (0.0 pps) to the click dimension seems crucially involved in producing these complex effects.

Time-Intensity Trading Ratios for Narrow-Band Transients

Narrow-band clicks (approximately 200 Hz wide) with center frequencies of 250, 1000, 4000, and 6300 Hz were given to three experienced listeners at interaural intensity differences (ΔI) of 3, 6, and 9 dB. A reference sensation level of 30 dB was used throughout, and listeners asked to center the click image with an opposing time difference (Δt). Although two ranges of compensatory time (Δt) could often center the image only the smaller times were considered. Trading-ratio slopes for the four transients, in order of increasing click frequency, were: 25, 20, 50, and 40 μsec/dB. Increasing the click bandwidth around the same center frequencies (while maintaining the sensation level constant at 30 dB) did not significantly affect the trading ratios. The trading-ratio results will be compared to some lateralization (jnd) data for time and for intensity to see whether both kinds of data indeed reflect the same underlying process.

ANALYSIS OF RESPONSE RATES DURING STIMULUS GENERALIZATION1

In the presence of one click frequency, the presses of two hungry rats on one of two levers were reinforced with food on variable-interval schedules; in the presence of a different click frequency, presses on the other lever were reinforced. In stimulus generalization tests, a variety of click frequencies were presented and reinforcement withheld. The test stimuli were found to exert control over which of the two levers the rats pressed, but not over the rate of pressing the selected lever. The results were interpreted as further evidence that intermediate rates in generalization gradients may be the result of the alternation of several distinct behavior patterns.

Stimulus generalization of response-position in the rat

Three rats were trained by food reinforcement to poke their noses into each of two 1–1/8 in. segments of a 10-in. slot. Two auditory click frequencies signalled whether a response in one segment or the other would be reinforced. Stimulus generalization gradients of location were then obtained in the presence of 4 click frequencies. Although the mean location varied continuously with stimulus value, responding tended to occur primarily around the 2 previously reinforced locations, according to bimodal distributions, with peaks of varying relative heights.

Periodicity Perception by Using Gated Noise

Gated white noise was used as a stimulus in a psychophysical experiment to determine the temporal resolution of the ear. Although exhibiting temporal periodicity of the envelope, gated while noise has a uniform power spectrum that possesses no information for a place mechanism of the ear. Four subjects varied the gating frequency to match this stimulus to a 0.1-msec click whose repetition frequency was set by the experimenter. All stimuli were 40 dB SL. Ungated noise was added to the gated noise to mask any switching transients. Fraction of time noise was gated on and filter conditions were set by the experimenter. For an on time fraction of 0.2 and 0.5, time information in the gated noise (all pass and 2400 cps high pass) could be utilized to match to a click frequency up to 750 cps. With 4800 cps high-pass gated noise, a weak timing signal was probably perceived up to 2000 cps. In a second part of the experiment, subjects attempted to lateralize gated, binaurally incoherent noise. A lateralized image could be formed up to a frequency of about 600 cps. The timing signal present in gated noise is not necessarily related to the percept of pitch, especially for high pass stimuli.

Response of single medial geniculate units to repetitive click stimuli.

The capacity of single units isolated in the medial geniculate of unanesthetized, paralyzed cats to respond to clicks delivered to the ear at rates between 1 and 200/sec. is described. Most units respond one-to-one at low click rates. When the interval between stimuli is shortened some stimuli fail to evoke response, and when it is made very brief the unit may respond only to the first click in the train. The click frequency at which a unit responds to 50% of the stimuli is reasonably stable, but can be modified by the administration of morphine.

Laws of motion of steam vessels

Hashtags have become a ubiquitous and seminal feature of social media; however, a comprehensive understanding of what motivates and predicts their use is yet to be addressed. To fill this gap, this research investigates motives of hashtag use and their effect on behavioral outcomes based on the Uses and Gratifications (U&G) approach. Through a two-phase mixed method data collection, we distill six motives of hashtag use in the context of Instagram: Self-presentation, Chronicling, Inventiveness, Information Seeking, Venting, and Etiquette. We find drivers for platform use to affect these motives, which, in turn, influence the frequency of clicking and adding hashtags, and the number of hashtags a user may employ in a post. Furthermore, we find potential influencers to be heavy users of hashtags, primarily driven by motives of self-presentation, and to score higher on narcissism, extraversion and self-monitoring than followers. We further assert the need for U&G studies to explicitly acknowledge the nature of social media that allows users to both consume and produce content. The findings hold important implications for social media managers and designers.