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Biomedical subjects

C W Newman

Publications and source records attributed to C W Newman.

At least 37 records · Page 2Linked to original sources

When paroxysmal positioning vertigo isn't benign.

The electronystagmographic auditory brainstem response and magnetic resonance imaging findings for a 33-year-old male with a 3.5 cm left vestibular schwannoma are presented. Of particular interest was the presence of an unusual positioning nystagmus following the Dix-Hallpike maneuver in the right head-hanging position. The patient demonstrated a nystagmus that was immediate in onset and not fatigueable upon repeated positioning. During positioning, the patient experienced a vertical bobbing sensation and dysphoria, but not rotational vertigo. Most importantly, the nystagmus had a predominant downbeating vertical component. the case illustrates the diagnostic significance of downbeating nystagmus elicited by the Dix-Hallpike maneuver.

Adult↗

Hearing loss in Paget's disease of bone: evidence of auditory nerve integrity.

Auditory brainstem responses (ABRs) were recorded in 64 ears with radiographically confirmed Paget's disease involving the skull. Responses were absent in eight ears, all of which had elevated high pure-tone thresholds. Auditory brainstem responses were interpreted as normal in 56 ears; none were abnormal. Computed tomography and digital image analysis were used to quantify internal auditory canal (IAC) dimensions. The midlength diameter and minimum diameter of the IAC of 68 temporal bones from subjects with Paget's disease were found to have no statistically significant relation to hearing thresholds. Increased IAC length showed a limited relation to reduced hearing level in pagetic subjects, possibly consistent with bossing adjacent to the porus acusticus. Findings support the principle that hearing loss in Paget's disease of bone is generally associated with intact auditory nerve function and also support a cochlear site of lesion.

Audiometry, Pure-Tone↗

The Henry Ford Hospital Headache Disability Inventory (HDI).

To quantify the impact of headache of daily living, we developed a 25-item headache disability inventory (HDI). The alpha version of the HDI (alpha-HDI) consisted of 40 items, each requiring a "yes" (four points), "sometimes" (two points), or "no" (zero points) response based on items derived empirically from case history responses of subjects with headache. From the alpha-HDI, we derived a 25-item beta version (beta-HDI) with the items subgrouped into functional and emotional subscales. The internal consistency/reliability was strong, as was construct validity. The test-retest reliability for the beta-HDI was acceptable for the total score and functional and emotional subscale scores. A 29-point change (95% confidence interval) or greater in the total score from test-retest must occur before the changes can be attributed to treatment effects. The HDI is useful in assessing the impact of headache, and its treatment, on daily living.

Adult↗

Tocotrienol and fatty acid composition of barley oil and their effects on lipid metabolism.

Barley oil was extracted with hexane from the grain of a high oil waxy hull-less barley. Twelve male broiler chicks were fed corn-based diets with either 10% barley oil, 10% corn oil or 10% margarine ad libitum for ten days. Total plasma cholesterol concentration of the chicks fed barley oil was 34% lower (p < 0.05) than that of the chicks fed margarine. Plasma low density lipoprotein cholesterol concentration of chicks fed barley oil was 53% and 59% lower (p < 0.05) than those of chicks fed corn oil and margarine, respectively. Plasma high density lipoprotein cholesterol and triglyceride concentration of the barley oil group were similar to those of the margarine but higher (p < 0.05) than those of the corn oil group. Chicks fed the barley oil gained more (p < 0.05) body weight than those fed the corn oil and margarine. Barley oil had an effect in suppression of TC and LDLC in chicks compared to margarine. Barley oil suppressed LDLC but not HDLC in chicks compared to corn oil. A greater weight gain of the chicks fed barley oil suggested that these chicks had normally functioning digestion and absorption. alpha-Tocotrienol and gamma-tocotrienol content of the barley oil were 24 and 17 times greater, respectively, than those observed in the corn oil, while the same fractions were not detectable in the margarine. Polyunsaturated fatty acid content of the barley oil was more than threefold that of margarine. These data suggest that alpha-tocotrienol and polyunsaturated fatty acids are hypocholesterolemic components in barley oil.

Animal Feed↗

The influence of hearing aid cost on perceived benefit in older adults.

Self-report hearing handicap scales are gaining widespread acceptance among clinicians as a technique for quantifying hearing aid benefit. Both auditory and nonauditory (e.g., personality, health, motivation) factors contribute to an individual's response to hearing loss and ultimately to perceived hearing aid benefit. Among the recognized extra-audiological variables, financial concerns may influence a hearing aid user's expectations regarding hearing aid benefit. The present study compared self-perceived benefit in 26 insured and 26 uninsured new hearing aid wearers using the Hearing Handicap Inventory for the Elderly (HHIE). HHIE scores at 3 weeks and 6 mo postfitting were equivalent between groups. The findings suggest that the HHIE may be used as an index of hearing aid benefit without concern that the source of funds required to purchase amplification may act as an uncontrolled variable.

Aged↗

False negative auditory brainstem response findings in vestibular schwannoma: case reports.

The false negative rate of the auditory brainstem response (ABR) for the detection of vestibular schwannoma (VS; acoustic neuroma) has been reported to range from 2 to 9 percent. The introduction of magnetic resonance with gadolinium contrast (Gd MRI) may be expected to raise the false negative rate, because smaller tumors can now be detected. We present two cases that illustrate some of the complex issues raised by the detection of small asymptomatic VS by Gd MRI that were missed by ABR. The role of ABR testing in the diagnosis and management of VS remains well established and will continue to evolve.

Ear Neoplasms↗

Reexamination of gender differences in the source location of N1m.

Gender differences in the source location of the auditory evoked field (AEF) component N1m have been reported previously in a small group of subjects. The present study was conducted to evaluate further the existence of gender differences in a larger sample. Neuromagnetic recordings of AEFs were obtained from young normal hearing subjects using a 1000-Hz tone burst presented at 60 dB hearing level (HL). No significant gender-related differences were observed for the N1m peak latencies following left and right ear stimulation. The stimulating parameters and larger sample used in the present study size may account for the difference in gender effects observed between the two studies.

Acoustic Stimulation↗

Effect of full-fat or defatted rice bran on serum cholesterol.

Rice bran has been shown to lower serum cholesterol in hamsters. Leghorn cockerel chicks were fed 60% full-fat rice bran (FFRB) and corn/soy (CS) diets with 0.5% added cholesterol. Both diets contained 18% protein. All reported parameters are on blood serum. Significant differences (p less than 0.05) were found in total cholesterol (TC), triglycerides (TG), high-density and low-density lipoprotein cholesterol (HDL and LDL). In a second study, chicks were fed FFRB, defatted rice bran (DFRB), and CS diets balanced for 18% protein, 14.47% total dietary fiber and 10.78% lipid with 0.5% added cholesterol. Both TC and TG were significantly lower (p less than 0.05) in chicks fed FFRB and CS diets. Significant differences were found in HDL values for all diets with FFRB exhibiting the highest mean value (155 mg/dl) and CS exhibiting the lowest mean value (114 mg/dl). All diets were significantly different (p less than 0.05) in LDL, with mean values of 249, 318 and 275 mg/dl for FFRB, DFRB and CS, respectively. FFRB appears to increase HDL and to lower LDL in chicks, but does not always affect TC, whereas DFRB may increase all three serum lipid components.

Animals↗

Barley beta-glucans alter intestinal viscosity and reduce plasma cholesterol concentrations in chicks.

Ninety-six 14-d-old male broiler chicks were divided into three dietary groups and fed a corn-soybean meal diet, a barley diet with beta-glucanase and that diet without beta-glucanase. All diets contained 4 g cholesterol/kg. Average daily body weight gain, plasma total cholesterol concentration, LDL cholesterol concentration and digestibility of lipids and protein were lowest (P < 0.05) in the chicks fed the barley diet without beta-glucanase and highest (P < 0.05) in the chicks fed corn-soybean meal diet. Supplementation of the barley diet with beta-glucanase resulted in greater (P < 0.05) average daily weight gain, plasma total and LDL cholesterol concentrations and digestibility of lipids. Viscosity of small intestinal digesta was greatest in chicks fed barley, lowest in those fed the corn-soybean diet and intermediate in chicks fed enzyme-treated barley. Significant (P < 0.01) negative correlations occurred between viscosity of the small intestinal contents and average daily weight gain, plasma total and LDL cholesterol concentrations, and digestibility of lipids and protein. A lower concentration of insoluble beta-glucans in small intestinal digesta of the chicks fed barley supplemented with beta-glucanase compared with the chicks fed the unsupplemented barley diet reflects hydrolytic activity of the supplemental beta-glucanase in the diet.

Animal Feed↗

Barley diets with different fat sources have hypocholesterolemic effects in chicks.

Saturated fat is known to elevate serum cholesterol, whereas soluble dietary fiber has a hypocholesterolemic effect. The objective of this study was to compare the effects of barley and wheat diets supplemented with five fat sources on lipid metabolism in chicks. In two separate experiments, broiler chicks were fed isonitrogenous diets containing 23% protein, 11.4% dietary fiber and 10% dietary fat for 17 d. Diets contained 60% either hull-less barley or red spring wheat, with either palm oil, dehydrated egg yolk, butter, tallow or corn oil. Growth, feed efficiency, plasma lipids, liver cholesterol, and fecal fat and dry matter were measured. All chicks fed wheat grew faster and had greater food efficiency than those fed barley. All barley-fed chicks had lower (P less than 0.0001) total plasma cholesterol concentration (3.1 to 4.0 mmol/L) than those fed wheat (6.0 to 11.3 mmol/L). Chicks fed palm oil with wheat had the highest total cholesterol, 11.3 mmol/L. Liver cholesterol concentration was higher (P less than 0.0001) for all wheat-fed chicks (22.8-86.4 mmol/g) compared with those fed barley (6.7 to 12.2 mmol/g). Fecal crude fat was higher (P less than 0.05) for chicks fed barley, and excreta dry matter was lower for barley-fed chicks. Results indicate that the high soluble fiber content of this barley exerts a hypocholesterolemic effect in chicks regardless of dietary fat source, possibly mediated through lowered fat absorption.

Animals↗

The effects of stimulus frequency and recording site on the amplitude and latency of multichannel cortical auditory evoked potential (CAEP) component N1.

Magnetoencephalographic (MEG) applications in auditory evoked field (AEF) recordings have demonstrated that both tonotopicity and amplitopicity exist in the auditory cortex. The present study was conducted to determine whether previously reported characteristics of the AEF could be identified in multichannel cortical auditory evoked potential N1e (e.g., the electrical correlate of the magnetically recorded N1m) component recordings. Multichannel auditory evoked potentials from 11 young normal adults were collected after monaural tone burst stimuli of 250, 1000, and 4000 Hz. Results demonstrated that N1e amplitudes after stimulation at 250 Hz were significantly larger than those obtained after stimulation at 1000 or 4000 Hz. These frequency-specific differences existed for latency as well. Responses obtained after stimulation at 250 Hz were, on the average, 13 msec longer than those obtained after stimulation at 1000 or 4000 Hz. Also, contralateral latencies were significantly shorter than ipsilateral latencies. Although the significant frequency-specific amplitude results support the findings of previous investigators, the frequency-related latency differences have not been described. An explanation of these differences may exist in the spatial differences in the reception areas for low- and high-frequency tones in the primary auditory cortex.

Acoustic Stimulation↗

Occurrence of auditory evoked field (AEF) N1M and P2M components in a sample of normal subjects.

A great deal of information about the characteristics of components N1m and P2m of the auditory evoked cortical fields (AEFs) has accumulated since the late 1970s. However, a number of fundamental issues have not been addressed. For instance, some previous investigators have suggested that P2m is present consistently in normals, whereas others suggest that when present, P2m is small in amplitude. Preliminary observations in this laboratory suggested that P2m is not observed consistently in normal subjects. Therefore, the specific aim of this investigation was to estimate the frequency of occurrence of the contralaterally recorded N1m and P2m after stimulation of right and left ears in normal subjects. Results demonstrated N1m to be present in all circumstances. Consistent with our preliminary observations, P2m was often absent, and moreso after stimulation of the left ear.

Adult↗

Growth and lipid metabolism as affected by feeding of hull-less barleys with and without supplemental beta-glucanase.

Three hull-less barleys, Washonupana (WSNP), Waxbar (WXB), and Bangsa (BGS), were fed to broiler chicks in 21% protein diets containing 0.5% cholesterol in replicate trials. A corn-based diet, with added cholesterol, served as a control. Alternate diets were supplemented with beta-glucanase (ENZ). beta-glucan content ranged from 4.9% to 6.1% and soluble dietary fiber (SDF) from 3.6% to 7.5% in the barleys. Data from the two trials were pooled for statistical analysis by the SAS General Linear Models procedure. In body weight gain, chicks fed WSNP-ENZ were lower (P less than 0.05) than all other treatments. The beta-glucanase supplement to the WXB and BGS barley tended to improve gains, but the differences were not significant for either barley. Feed to gain ratios were lowest (P less than 0.0001) for corn fed chicks and lower (P less than 0.05 to P less than 0.0001) for those fed the barley + ENZ diets compared to barley -ENZ. Chicks fed barley diets had lower (P less than 0.05) total serum cholesterol (TSC) and LDL-cholesterol than those fed corn diets, regardless of ENZ supplementation. For chicks on barley -ENZ diets, TSC levels for WSNP, WXB, and BGS were 146, 152, and 142 mg/dl respectively and for chicks on barley + ENZ diets, 218, 200, and 178 mg/dl. LDL-cholesterol levels followed the same trend and there was little difference in serum triglycerides. The BGS + ENZ lowered TSC 30% from the corn control compared to 10.7% and 18% for WSNP + ENZ and WXB + ENZ, suggesting additional hypocholesterolemic factors, possibly tocotrienol and SDF other than 1----3, 1----4 beta-D-glucans.

Animals↗

Auditory evoked cortical magnetic field (M100-M200) measurements in tinnitus and normal groups.

Recently, Hoke et al. (1989) and Pantev et al. (1989) demonstrated that the auditory evoked cortical magnetic field (AECMF) M100 component was larger, and M200 was smaller and occurred later in subjects with unilateral tinnitus compared with normal subjects. These group amplitude differences resulted in an M200/M100 amplitude ratio that was smaller for the subjects with tinnitus. The purposes of the present investigation were to: 1) extend the observations of Hoke et al. (1989), and, 2) determine whether contralateral AECMF differences existed following stimulation of the non-tinnitus and tinnitus ears of patients with tinnitus. Neuromagnetic AECMF recordings were recorded from 25 young normal hearing and 14 patients with unilateral tinnitus and hearing loss. The results failed to support the findings of Hoke et al. (1989). Specifically, there is no evidence suggesting that the M100 amplitude is larger, the M200 latency later, or, the M200/M100 amplitude ratios smaller, when the two samples are compared. Additionally, there were no differences in the amplitudes or latencies of M100 or M200 when results from stimulation of the tinnitus and non-tinnitus ears of tinnitus subjects were compared.

Adult↗

The effects of rate, sequencing, and memory on auditory processing in the elderly.

Auditory sequencing, rate, and memory were evaluated in three age groups with a series of subtests that require the identification of tones (Repetition Test; Tallal & Piercy, 1973). The older elderly group (M age = 80), but not the younger elderly group (M age = 70), performed significantly (p less than .05) poorer than the young adult group (M age = 25) when auditory memory of 4 and 5 tones was required and when the interstimulus interval was decreased. Performance was not related to hearing sensitivity, thus suggesting that changes in the auditory mechanism that occur with age may encompass more than a loss of hearing sensitivity. Moreover, performance on the Repetition Test did correlate with memory for digits, which indicates a relationship between auditory processing and higher cortical functions.

Acoustic Stimulation↗

Test-retest reliability of the hearing handicap inventory for adults.

The test-retest reliability of the Hearing Handicap Inventory for Adults (HHIA) was assessed on a sample of 28 hearing-impaired adults. Reliability estimates were obtained to set the stage for using the HHIA as an outcome measure in aural rehabilitation. The test-retest reliability was quite high (r = 0.97) and the standard error of measurement was low for the HHIA and its screening version (HHIA-S). In light of the psychometric adequacy, the HHIA and HHIA-S have potential as indices of hearing aid benefit in hearing-impaired adults.

Adult↗

Probe-tube measurements of ALDs: uniformity, linearity and frequency response differences.

A Madsen IGO 1000 was used to assess six assistive listening devices (ALDs) (Sound Plus Infrared, Minicon Induction Floor Loop, Phonic Ear Phonear, Radio Shack Realistic Personal Amplifier, Williams Sound PockeTalker with induction neck loop and Williams Sound PockeTalker permanently wired) worn by a single subject. In situ measures determined product uniformity of three samples of each of the same ALDs, volume control linearity, ear coupling effects on canal resonance and frequency response differences. ALDs were generally uniform, although the two PockeTalker models showed gain variability at all frequencies. Frequency response changes controlled by high boost switches in the Realistic were also found not to be uniform. The earbud had almost no effect on canal resonance, while lightweight headphones caused a slight loss of canal resonance. Non-telecoil coupled devices had broader/flatter responses than telecoil coupled devices. Average differences between telecoil and non-telecoil coupling were minimal. Probe-tube measurements were found to be a feasible means of assessing ALDs in situ.

Acoustic Impedance Tests↗

Differences in superficial and deep source contributions to middle latency auditory evoked potential Pa component in normal subjects and patients with neurologic disease.

Multichannel brain-mapped middle latency auditory evoked potential (MLAEP) data obtained from 15 normal subjects and three neurologically impaired subjects using the common average reference (CAR) were converted off-line to source current density (SCD). This technique is sensitive to activity generated in the superficial cerebral cortex. The SCD maps were subtracted from the CAR maps (CAR-SD). The derived CAR-SD maps are believed to represent the proportion of scalp-recorded activity that is generated deep to the cerebral cortex. Topographic analysis of this data manipulation technique supports the hypothesis that Pa originated from within the temporal lobes bilaterally as well as from a deeper subcortical system.

Adult↗