A focused exercise regimen improves clinical measures of balance in patients with peripheral neuropathy.

OBJECTIVE: To determine the effect of a specific exercise regimen on clinical measures of postural stability and confidence in a population with peripheral neuropathy (PN). DESIGN: Prospective, controlled, single blind study. SETTING: Outpatient clinic of a university hospital. PARTICIPANTS: Twenty subjects with diabetes mellitus and electrodiagnostically confirmed PN. INTERVENTION: Ten subjects underwent a 3-week intervention exercise regimen designed to increase rapidly available distal strength and balance. The other 10 subjects performed a control exercise regimen. MAIN OUTCOME MEASURES: Unipedal stance time, functional reach, tandem stance time, and score on the activities-specific balance and confidence (ABC) scale. RESULTS: The intervention subjects, but not the control subjects, showed significant improvement in all 3 clinical measures of balance and nonsignificant improvement on the ABC scale. CONCLUSION: A brief, specific exercise regimen improved clinical measures of balance in patients with diabetic PN. Further studies are needed to determine if this result translates into a lower fall frequency in this high-risk population.

Medicaid managed care in New York City: recent performance and coming challenges.

OBJECTIVES: This study evaluated New York City's voluntary Medicaid managed care program in terms of health care use and access. METHODS: A survey of adults in Medicaid managed care and fee-for-service programs during 1996-1997 was analyzed. RESULTS: Responses showed significant favorable risk selection into managed care but little difference in use of health care services. Although some measures of access favored managed care, many others showed no difference between the study groups. CONCLUSIONS: The early impact of mandatory enrollment will probably include an increase in the average risk of managed care enrollees with little change in beneficiary use and access to care.

Ipsilateral loudness adaptation over multiple intensity levels.

Could monaural loudness adaptation be a simple artifact of psychophysical contrast? From adaptation data based on the Ipsilateral Comparison Paradigm (ICP), A. J. Dange, J. S. Warm, E. M. Weiler, and W. N. Dember (1993) concluded that loudness adaptation was not an artifact of psychophysical contrast, but their conclusion was dependent on results from one intensity. This study, involving multiple intensities, re-examined the issue of contrast versus adaptation and generally supported the conclusions of Dange et al. The results also showed an unexpected asymmetry of adaptation based on the direction of the referent modulation used with the ICP technique. Some implications are discussed.

Determining the dispersions of the fifth- and seventh-order nonlinear optical susceptibilities of a poly(4-BCMU) film through electroabsorption spectroscopy.

The dispersions of the fifth- and seventh-order nonlinear optical susceptibilities, chi((5))(113333) and chi((7))(11333333) , respectively, of a polydiacetylene film, poly(4-BCMU), are determined through electroabsorption spectroscopy. To our knowledge this is the first time that a spectrum of seventh-order nonlinear optical susceptibility has been obtained by means of electro-optic measurements.

Abnormalities of ICP loudness adaptation at 1000 Hz associated with higher frequency (cochlear) loss.

Individuals with higher frequency hearing loss, when tested at 1000 Hz, showed more loudness adaptation at 40 dB HL and less at 60 dB HL (ISO) than the normal listeners. Adaptation was measured with the monaural method described by Weiler, Sandman and Pederson (1981), now called the Ipsilateral Comparison Paradigm (ICP) by Dange et al. (1993). Using the same method Korman (1986) had shown that a complex combination of stimulus conditions, including intensity, produced differences between a similar group with high frequency hearing loss and normals. The current results confirm the value of this method for studying adnormalities in the loudness function at middle intensities. Because it is a quick and reliable method we believe it has potential for clinical use but acknowledge considerable research and development is necessary.

Visual evoked potentials in early Alzheimer's dementia: an exploratory study.

Topographical maps of visual evoked potentials (VEPs) were recorded from 10 possible Alzheimer's disease (AD) patients and 10 control subjects. The purpose of the study was to determine if the two types of VEPs could function as a diagnostic screening for AD. Results of the statistical analysis did not reveal any latency differences between VEPs for the components elicited by either the pattern shift visual evoked potential (PSVEP)--or flash visual evoked potential (FVEP)--elicited components for AD patients compared with the control subjects; however, the information provided insight into results that are frequently lost with conventional evoked potential data. Statistically significant differences in amplitude were found between the P1 and the N2 of the PSVEP at 124, 126, and 130 ms, and at 116 ms for the FVEP.

Four triggering factors in loudness adaptation.

A factor analysis was used to determine whether induced loudness adaptation (Botte, Canevet, & Scharf, 1982; Scharf, 1983) and adaptation measured by Hood's (1950) classic Simultaneous Dichotic Loudness Balance technique (SDLB) would cluster on the same factors. The two phenomena did not cluster on the same factors; thus, induced adaptation cannot replace SDLB adaptation. Four independent factors that trigger auditory adaptation were identified in the factor analysis.

Monaural auditory adaptation of reaction times at .5, 1, and 3 kc/s.

All procedures to measure auditory adaptation depend at least indirectly upon some subjective judgment of loudness, with the exception of the reaction-time (RT) study of Davis and Weiler (Brit. J. Audiol., 1976, 10, 102-106). We used a variant of the Davis-Weiler RT method to measure monaural adaptation at the end of tones of 7 min duration at .5, 1, and 3 kc/s at 60 db SPL, in 62 normal-hearing young adults. Adaptation was expressed as an increase in RT in msec post- vs pre-adaptation in response to a 1-sec probe tone at 10 kc/s at 70 db SPL presented simultaneously with the adapting tone, either (1) in the middle of a 2-sec burst of the adaptation tone prior to the beginning of the 7-min adaptation session (pre-adaptation measure), or (2) during the last seconds (S alerted) of the continuing adaptation tone (post-adaptation measure). Significant pre-post RT differences, collapsed over pre-post measures and over ears, were found at all 3 frequencies (p less than .0001), indicating that the Monaural Heterophonic RT (MHRT) procedure can indeed be used as an objective measure of auditory adaptation. The mean RTs across pre- and post-adaptation measures were 221.9, 217.6, and 228.0 msec in the usual frequency order, significantly different (p less than .0001). Adaptation (i.e., increased RT after 7 min of adaptation) at .5, 1, and 3 kc/s was 36.9, 28.5, and 21.6, respectively. This effect introduced a significant interaction between frequency and adaptation (p less than .001). To transfer from auditory adaptation in reduced RT in msec by the MHRT method to adaptation in reduced phons in db, it will be necessary to construct, perhaps for every S, a table of RTs for a sufficient selection of levels at the relevant frequencies.

Monaural and binaural adaptation in sequence: SDLB analogue?

Magnitude estimates (M.E.) of loudness of a 1-kc/s tone in the R ear at 60 db SPL were required over three 3-phase sessions from 15 normal-hearing young adults. The initial tone in the session was arbitrarily assigned a value of "60 units" in instructions to the S. The session was arranged to be analogous to that commonly used in Simultaneous Dichotic Loudness Balancing (SDLB). In a baseline Phase I in any of 3 sessions both ears received identical, simultaneous, intermittent stimulation. In each session, one of 3 duty cycles (randomized) were used (all on-times of .5 sec, off-times of .5, 4.5, or 24.5 sec). An M.E. judgment was requested every 10 sec for just over 1 min. Then immediately in Phase II the L ear received nothing while the R ear received continuous stimulation at 60 db SPL for 7 min, with M.E. Judgements requested every 10 sec during Min 1 and every min thereafter. Then in Phase III the R ear continued to receive continuous stimulation at 60 db SPL for 1 min while in the contralateral ear the condition of Phase I was re-introduced. M.E. loudness judgements for the R ear were requested as in Phase I. During Phase I there was, as expected, no loudness adaptation. During the adapting Phase II, M.E. group values declined progressively and significantly, but without significant differences among duty cycles. M.E. values in Phase III continued to decline significantly even though the contralateral ear was being given intermittent stimulation (irrespective of duty cycle). Previous studies had found that, for most listeners, M.E. loudness adaptation does not occur when the continuous stimulation is presented by itself. As far as is known, the present study is the first M.E. loudness adaptation study to present binaural intermittent stimulation before the continuous monaural stimulus. It is suggested that the redundancy of the continuous monaural stimulation, in comparison with the similar intermittent stimulus, is associated with the diminution of loudness.

Auditory adaptation: notes on power and parabolic curve fitting across intensity: II.

The classic Simultaneous Dichotic Loudness Balance (SDLB) procedure for the study of auditory adaptation was used by Weiler and Hood (1977) in a successful test of a model for predicting adaptation in db at intensities above the initial baseline values, using a linear approximation across levels. When Balzer et al (Brit. J. Audiol., 1984, 18, 49-50) fitted curves for simple baseline adaptation data from four studies based on SDLB data, they reported good fits for the Gompertz technique and for a parabolic formula, but did not test the relative goodness of fit for the linear formula, nor for power approximations as Stevens (1975) might have proposed. The present study makes use of the data used by Balzer et al but examines a linear fit as well as two approximations to Stevens' power law. The present finding that the linear approximation is the least efficient examined would suggest that the Weiler and Hood model should be re-examined to determine the degree to which the model can be improved by use of a curvilinear baseline fit. In addition, it might be noted that the curvilinear formulae, of necessity, involve two or more stages. It is the the current effort of this laboratory to determine whether this reflects a multifactor basis to the classic SDLB adaptation, as well as results from other adaptation techniques.

Auditory adaptation: notes on power and parabolic curve fitting across intensity and time. I.

The classic procedure for the study of auditory adaptation has been the method of Simultaneous Dichotic Loudness Balance ( SDLB ). Data from four publications ( Jerger , 1957; Palva and Karja , 1969; Weiler , Loeb and Alluisi , 1972 and Weiler and Hood, 1977) were combined to yield values extending from 20 dB to 80 dB average sensation level. A growth curve was fitted to the data by means of the Gompertz curve-fitting technique. A close fit was obtained, and a somewhat closer fit was found using a parabolic curve. In addition to the average data for SDLB adaptation across test intensities, the Gompertz method was used to fit the course of adaptation over time for one additional study ( Thwing , 1955).

Magnitude estimates of loudness adaption at 60 dB SPL.

Previous reports indicate that adaptation measured by the technique of successive magnitude estimations is not found above 30 dB SL (Fishken et al., 1977; and others). Although the present study confirmed this finding at 60 dB SPL for the original procedure, it was found that a modification of the magnitude estimation procedure resulted in significant loudness adaptation at this intensity. Introduction of a 20-dB increment for 5 s, every 30 s, resulted in a marked and statistically significant decline in successive loudness judgements of the 60-dB tone. In addition, the decline in reported loudness magnitude was cumulative and progressive throughout the 7-min duration of the monaural stimulus. This is typical of classical results found with simultaneous dichotic loudness balances.