FO gives voicing information even with unambiguous voice onset times.

The voiced/voiceless distinction for English utterance-initial stop consonants is primarily realized as differences in the voice onset time (VOT), which is largely signaled by the time between the stop burst and the onset of voicing. The voicing of stops has also been shown to affect the vowel's FO after release, with voiceless stops being associated with higher FO. When the VOT is ambiguous, these FO "perturbations" have been shown to affect voicing judgments. This is to be expected of what can be considered a redundant feature, that is, that it should carry a distinction in cases where the primary feature is neutralized. However, when the voicing judgments were made as quickly as possible, an inappropriate FO was found to slow response time even for unambiguous VOTs. This was true both of FO contours and level FO differences. These results reinforce the plausibility of tonogenesis, and they add further weight to the claim that listeners make full use of the signal given to them, even when overt labeling would seem to indicate otherwise.

Gradient effects of fundamental frequency on stop consonant voicing judgments.

The post-stop-release rise or fall of fundamental frequency (F0) is known to affect voicing judgments of syllables with ambiguous voice onset times (VOTs). In 1986, Silverman claimed that the critical factor was not direction of F0 change but rather its direction relative to the intonational contour. He further claimed that only F0s that start above and fall to the contour have an effect proportional to the size of the frequency change; F0s that rise to the contour by different amounts were claimed to be equivalent. In our first experiment, we examined the effect on voicing judgments of five onset F0s preceding a single, flat contour. Only falling F0s were differentiated in the first set of judgments, but after increased exposure to the syllables, even F0s below the contour differentially affected the voicing judgment. In a second experiment, the contour of the final part of the syllable was flat, rising or falling. F0 contour affected the judgments, as did onset F0s, but the two factors did not interact, indicating that the onset values were not being judged by reference to the contours. However, the contour which was predicted to result in more voiceless judgments also ended at a higher F0 in the vowel, and another effect of voicing is that the F0 is higher throughout the vowel after voiceless stops. In a third experiment, F0 contours were created to contrast contour and mean F0. The effect of the F0 during the vocalic segment appeared to be attributable to the average F0 rather than the contour. In all three experiments, the F0 onset values contributed to the voicing judgment whether they were above or below the putative intonation contour. The contribution of the lower F0s, while significant, was not as great as that of the higher F0s, which argues for a noncategorical contribution of intonation.

Neurogenic bladder: a guide to evaluation and management.

The function of voiding, whether normal or abnormal, can be symbolized by a universal formula which is based on the variables of expulsion and retention of urine, timing of urine flow, and emptying of the bladder. A guide for evaluation and management of the neurogenic bladder is derived from the formula by considering the component parts of the variables separately. A minimally invasive method of evaluation and an orderly method of conservative management are described which are based upon the guide. Early application of these principles can reestablish more normal parameters of the variables and thus avoid complications.

Vowel height and the perception of consonant nasality.

By means of an articulatory synthesizer, the perception of the oral-nasal distinction in consonants was explored experimentally. This distinction was chosen because it is achieved by a very simple articulatory maneuver and because it is phonologically relevant in virtually every language. Lowering the velum in equal increments provided continua of CV syllables varying in size of velopharyngeal port which were divided perceptually into /d/ and /n/ categories by American English listeners. To test the hypothesis that the coarticulation of these nasal consonants with lower (more open) vowels requires a larger area of velopharyngeal coupling to give a nasal consonant precept, three oral-nasal continua incorporating the vowels /i/, /delta/, and /alpha/, respectively, were presented for identification. The results were compared with those of A. S. House and K. N. Stevens [J. Speech Hear. Disord. 21, 218-232 (1956)] and A. S. House [J. Speech Hear. Disord. 22, 190-204 (1957)] obtained with steady-state vowels and consonantal murmurs and with those of M. H. L. Hecker [J. Acoust. Soc. Am. 34, 179-188 (1962)]. Three conclusions emerged. First, the relationship between vowel height and the amount of velopharyngeal coupling needed for a nasal precept occurs in conditions where subjects are required to make linguistically relevant judgments. Second, the relationship can arise in conditions where vocalic coarticulation is present. Third, the relationship is not confined to vowels but can also be observed in the case of dynamically articulated consonants. One of the continua was also used for discrimination experiments, which yielded the classical pattern of high discriminability at the category boundary.

Pharmacological rebound: a tool in the evaluation of antispasticity drugs.

Twelve spastic patients with traumatic transverse myelopathies participated in a two-stage, double-blind crossover study using BA-34647 (a new experimental antispasticity drug by Ciba-Geigy) and placebo. Clinical measurements of spasticity were performed before, during and after each stage. Six patients had excellent results receiving a regimen of BA-34647 but not when receiving placebo. Four patients had fair-to-good results with both BA-34647 and placebo. One patient had no significant changes when receiving either drug or placebo, the effective dose not being reached due to excessive body weight. One patient had a shortened trial due to pain and diminished function caused by excessive spasticity. Abrupt changes in post-treatment symptomatology (increase in spasticity) occurred in all six patients who demonstrated excellent results and in all four patients with fair-to-good results. In each of these cases, the increase followed the discontinuation of BA-34647. In no case was there an increase of spasticity following discontinuation of placebo. The effectiveness of an antispasticity drug may be too subtle to be perceived subjectively and objectively. The rebound phenomenon is evidence that a pharmacodynamic effect, though minor, was present.

Bladder training: its role in evaluating the effect of an antispasticity drug on voiding in patients with neurogenic bladder.

Fourteen patients with spinal cord damage were treated with Ba-34647 (Lioresal, Ciba-Geigy), a new antispasticity drug. The treatment was initiated for excessive skeletal muscle spasticity and voiding difficulty. Seven of the patients had been wearing indwelling catheters and seven were catheter-free. The former were given trials at voiding after removal of catheters; the usual assistive methods common to most bladder training regimens were administered. Despite this, the trials were unsuccessful in reducing residual urine to acceptable levels. With addition of therapeutic doses of the drug without the training regimen, voiding trials were also unsuccessful excepting the response of one patient. The drug plus the training regimen was effective in reducing residual urine to acceptable levels in all patients. On discontinuing or decreasing the dosages of the drug, there was gradual but rapid build-up of residual urine despite the active training regimen. Restoration of effective dosage again led to satisfactory voiding function in all patients. The catheter-free group suffered from frequency, nocturia, and bed-wetting owing to excessive residual urine despite the employment of active training regimens. With addition of optimal dosages of Ba-34647, these problems were markedly reduced. They increased with drug discontinuation or dosage decrease and again improved upon restoration of effective doses. Bladder training, including active assistance to the expulsion of urine, is essential to the evaluation of antispasticity drugs for their effect on voiding.