Effects of Aging on the Precedence Effect in Sound Localization

1990 ◽  
Vol 33 (4) ◽  
pp. 654-659 ◽  
Author(s):  
Jerry L. Cranford ◽  
Martha Boose ◽  
Christopher A. Moore
Keyword(s):  
Sound Localization ◽  
Normal Subjects ◽  
Precedence Effect ◽  
Elderly Subjects ◽  
Fused Image ◽  
Young Subjects ◽  
Effects Of Aging ◽  
Young And Elderly Subjects

The precedence effect in sound localization can be evoked by presenting identical sounds (e.g., clicks) from pairs of loudspeakers placed on opposite sides of a subject’s head. With appropriate inter-loudspeaker delays, normal subjects perceive a fused image originating from the side of the leading loudspeaker. Separate tests at loudspeaker delays ranging from 0 to 8 ms were presented to groups of young and elderly subjects. At 0 ms delay, young subjects perceived the fused image to be located halfway between the loudspeakers; at progressively longer delays, the image was perceived closer to the leading loudspeaker. Significant numbers of elderly subjects exhibited discrimination difficulties with delays below 0.7 ms.

Influences of Age and Hearing Loss on the Precedence Effect in Sound Localization

1993 ◽  
Vol 36 (2) ◽  
pp. 437-441 ◽  
Author(s):  
Jerry L. Cranford ◽  
Marci A. Andres ◽  
Kristi K. Piatz ◽  
Kay L. Reissig
Keyword(s):  
Hearing Loss ◽  
Sound Localization ◽  
Detrimental Effect ◽  
Precedence Effect ◽  
Elderly Subjects ◽  
Elderly Persons ◽  
Hearing Sensitivity ◽  
Two Factors ◽  
Tentative Evidence ◽  
Young And Elderly Subjects

Cranford, Boose, & Moore (1990a) reported that many elderly persons exhibit problems in perceiving the apparent location of fused auditory images in a sound localization task involving the Precedence Effect (PE). In the earlier study, differences in peripheral hearing sensitivity between young and elderly subjects were not controlled. In the present study, four groups of young and elderly subjects, matched with respect to age and the presence or absence of sensorineural hearing loss, were examined to determine the effects of these two factors on performance with the PE task. Although significantly poorer performances on the PE task were found to be associated with both increased age and hearing loss, additional tentative evidence was obtained that the presence of hearing loss may have a relatively greater detrimental effect on the performance of at least some elderly subjects than it does on younger persons.

Pyridostigmine partially restores the GH responsiveness to GHRH in normal aging

1990 ◽  
Vol 123 (2) ◽  
pp. 169-173 ◽  
Author(s):  
E. Ghigo ◽  
S. Goffi ◽  
E. Arvat ◽  
M. Nicolosi ◽  
M. Procopio ◽  
...  
Keyword(s):  
Normal Subjects ◽  
The Elderly ◽  
Normal Aging ◽  
Elderly Subjects ◽  
Plasma Growth Hormone ◽  
Gh Secretion ◽  
Combined Administration ◽  
Basal Plasma ◽  
Young Subjects ◽  
Plasma Gh

Abstract. In 11 elderly normal subjects and in 17 young healthy subjects we studied the response of plasma growth hormone to GH-releasing hormone (GHRH(29), 1 μg/kg iv) alone and preceded by pyridostigmine ( 120 mg orally 60 min before GHRH), a cholinesterase inhibitor likely able to suppress somatostatin release. The GH response to pyridostigmine alone was also examined. Basal plasma GH levels were similar in elderly and young subjects. In the elderly, GHRH induced a GH rise (AUC, median and range: 207.5, 43.5-444.0 μg · 1−1 · h−1) which was lower (p = 0.006) than that observed in young subjects (548.0, 112.5-2313.5 μg · 1−1 · h−1). The pyridostigmine-induced GH rise in the elderly was similar to that in young subjects (300.5, 163.0-470.0 vs 265.0, 33.0-514.5 μg · 1−1 · h−1). Pyridostigmine potentiated the GH responsiveness to GHRH in both elderly (437.5, 152.0-1815.5 μg · 1−1 · h−1; p = 0.01 vs GHRH alone) and young subjects (2140.0, 681.5-4429.5 μg · 1−1 · h−1; p = 0.0001 vs GHRH alone). However, the GH response to pyridostigmine + GHRH was significantly lower (p = 0.0001) in elderly than in young subjects. In conclusion, the cholinergic enhancement by pyridostigmine is able to potentiate the blunted GH response to GHRH in elderly subjects, inducing a GH increase similar to that observed after GHRH alone in young adults. This finding suggests that an alteration of somatostatinergic tone could be involved in the reduced GH secretion in normal aging. However, a decreased GH response to combined administration of pyridostigmine and GHRH in elderly subjects suggests that other abnormalities may coexist, leading to the secretory hypoactivity of somatotropes.

FRACTAL CHANGES IN HEART RATE DYNAMICS WITH AGING AND HEART FAILURE

2003 ◽  
Vol 03 (01) ◽  
pp. L83-L89 ◽  
Author(s):  
L. GUZMAN-VARGAS ◽  
E. CALLEJA-QUEVEDO ◽  
F. ANGULO-BROWN
Keyword(s):  
Heart Failure ◽  
Congestive Heart Failure ◽  
Fractal Dimension ◽  
Elderly Subjects ◽  
Crossover Point ◽  
Healthy Elderly ◽  
Fractal Organization ◽  
Heart Rate Dynamics ◽  
Young Subjects ◽  
Effects Of Aging

In this work we analyze interbeat cardiac time series arising of three groups: healthy young and healthy elderly subjects and patients with congestive heart failure. We use the fractal dimension method proposed by Higuchi. We find that fractal organization is different for each group. In the case of healthy young subjects only one value of the fractal dimension is necessary to fit the interbeat data, whereas in the cases of healthy elderly and patients with congestive heart failure a crossover behavior in the fractal dimension is present but in opposite directions. By means of a "zoom" on the hinges of the crossover point interesting effects of aging are presented. Finally, we discuss our results in the context of heart interbeat dynamics.

scholarly journals Cortical thickness of the tibial diaphysis reveals age- and sex-related characteristics between non-obese healthy young and elderly subjects depending on the tibial regions

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Keisuke Maeda ◽  
Tomoharu Mochizuki ◽  
Koichi Kobayashi ◽  
Osamu Tanifuji ◽  
Keiichiro Someya ◽  
...  
Keyword(s):  
Cortical Thickness ◽  
Structural Characteristics ◽  
Reference Points ◽  
Elderly Subjects ◽  
Tibial Diaphysis ◽  
Related Difference ◽  
Age Related ◽  
Young Subjects ◽  
Young And Elderly Subjects ◽  
Age And Sex

Abstract Purpose This study aimed to evaluate the age- and sex-related characteristics in cortical thickness of the tibial diaphysis between non-obese healthy young and elderly subjects as reference data. Methods The study investigated 31 young subjects (12 men and 19 women; mean age, 25 ± 8 years) and 54 elderly subjects (29 men and 25 women; mean age, 70 ± 6 years). Three-dimensional estimated cortical thickness of the tibial diaphysis was automatically calculated for 5000–9000 measurement points using the high-resolution cortical thickness measurement from clinical computed tomography data. In 12 assessment regions created by combining three heights (proximal, central, and distal diaphysis) and four areas of the axial plane at 90° (medial, anterior, lateral, and posterior areas) in the tibial coordinate system, the standardized thickness was assessed using the tibial length. Results As structural characteristics, there were no differences in the medial and lateral thicknesses, while the anterior thickness was greater than the posterior thickness in all groups. The sex-related difference was not shown. As an age-related difference, elderly subjects showed greater or lesser cortical thickness than the young subjects, depending on the regions of the tibia. Conclusions Cortical thickness was different depending on sex, age, and regions in the tibia. The results of this study are of clinical relevance as reference points to clarify the causes of various pathological conditions for diseases. Level of evidence Level 3.

Tracking of a “Moving” Fused Auditory Image Under Conditions that Elicit the Precedence Effect

1990 ◽  
Vol 33 (1) ◽  
pp. 141-148 ◽  
Author(s):  
Christopher A. Moore ◽  
Jerry L. Cranford ◽  
Angela E. Rahn
Keyword(s):  
Multiple Sclerosis ◽  
Sound Localization ◽  
Daily Life ◽  
Normal Subjects ◽  
Great Accuracy ◽  
Precedence Effect ◽  
Neural Function ◽  
Auditory Image ◽  
Conventional Tests ◽  
Temporal Lobe Lesions

Pursuit auditory tracking of a fused auditory image (FAI), based on stimulus conditions known to elicit the precedence effect phenomenon in sound localization, was investigated in 36 normal subjects and in a small group of subjects with known neuropathology. Movement of the FAI was simulated by incrementally varying the delay between two clicks presented, one each, from two loudspeakers placed on opposite sides of the listener. The group of normal listeners tracked the movement of the FAI without difficulty and with great accuracy; the perceived location of the FAI varied linearly with the interspeaker delay. The sensitivity of the task in detecting neural timing or integration deficits was investigated in 5 subjects with neuropathology, including subjects with unilateral temporal lobe lesions, multiple sclerosis, or dyslexia. These disorders, previously shown to disrupt neural timing, yielded characteristic patterns of tracking inaccuracy for this task. These subjects had no difficulty localizing either a moving unitary click source or sounds in daily life. These data support the suggestion that sound localization using stimulus conditions known to elicit the precedence effect places greater demands on neural timing and integration than conventional tests of localization, and may provide a more sensitive index of neural function.

scholarly journals Clinafloxacin Pharmacokinetics in Subjects with Various Degrees of Renal Function

2001 ◽  
Vol 45 (9) ◽  
pp. 2536-2542 ◽  
Author(s):  
Edward J. Randinitis ◽  
Jeffery R. Koup ◽  
George Rausch ◽  
Robert Abel ◽  
Nicola J. Bron ◽  
...  
Keyword(s):  
Renal Function ◽  
Severe Renal Impairment ◽  
Pharmacokinetic Profile ◽  
Elderly Subjects ◽  
Open Label ◽  
Pharmacokinetic Profiles ◽  
Age Related ◽  
Elimination Half ◽  
Young Subjects ◽  
Young And Elderly Subjects

ABSTRACT As the primary route for elimination of clinafloxacin is renal clearance (CLR) of unchanged drug, studies were conducted to determine the pharmacokinetic profile of clinafloxacin following administration to young and elderly subjects, subjects with various degrees of renal function, and subjects requiring dialysis. These were open-label studies in which subjects received single oral clinafloxacin doses. Sixteen young subjects (18 to 35 years old) and 16 elderly subjects (>65 years old) were enrolled in a study comparing pharmacokinetic profiles of clinafloxacin in young and elderly subjects. Twenty subjects having various degrees of renal function were enrolled into one of three groups based on degree of renal function as measured by creatinine clearance (CLCR). Twelve subjects with severe renal impairment requiring dialysis enrolled in a third study. Clinafloxacin was generally well tolerated by all subjects. Clinafloxacin pharmacokinetic profiles in elderly subjects were dependent only on age-related decreases in renal function. Clinafloxacin maximum concentrations in plasma, areas under the concentration-time curves, and terminal elimination half-life values increased with decreasing CLCR values. Total apparent body clearance of clinafloxacin from the plasma after oral administration (CLoral) and CLR were dependent on CLCR according to the following relationships: CLoral = 2.3 · CLCR + 77 and CLR = 1.74 · CLCR. Hemodialysis had no significant effect on clinafloxacin clearance. Based on the relationship between CLCR and clinafloxacin CLoral and CLR values, the clinafloxacin dose should be halved in patients having a CLCR of <40 ml/min. Further dose adjustment is not warranted in patients requiring hemodialysis.

Effects of aging on human plasma renin: simultaneous multiple assays of enzyme activity and immunoactivity of plasma renin

1989 ◽  
Vol 120 (1) ◽  
pp. 81-86 ◽  
Author(s):  
Jitsuo Higaki ◽  
Ryuichi Morishita ◽  
Toshio Ogihara ◽  
Masaru Nishiura
Keyword(s):  
Plasma Renin Activity ◽  
Plasma Renin ◽  
Normal Subjects ◽  
The Elderly ◽  
Renin Activity ◽  
Elderly Subjects ◽  
Plasma Renin Concentration ◽  
Active Renin ◽  
Effects Of Aging ◽  
Renin Content

Abstract. The effects of aging on plasma renin in normotensive volunteers were evaluated by conventional indirect RIA of angiotensin I and a newly developed direct RIA. Plasma renin activity and the plasma concentration of active renin measured by radiometric assay with monoclonal antibody were significantly lower in 14 subjects over 60 years than in 15 subjects under 60 years (plasma renin activity: 0.5 ± 0.1 vs 1.7 ± 0.4 nmol · 1−1 · h−1, P< 0.01; plasma active renin: 0.50 ± 0.05 vs 0.87 ± 0.13 pmol/l, P< 0.01, means ± sem), wheres neither the total renin activity nor the total plasma renin concentration measured by the newly developed immunometric assay were different in the two groups. In another study, the plasma renin concentration, total renin concentration and immunoreactive total renin concentration measured by direct RIA with polyclonal antibody were determined in 17 young (<60 years) and 12 elderly (≧60 years) subjects. Plasma renin concentration was significantly lower in the elderly subjects (1.7 ± 0.2 nmol · 1−1 · h−1) than in young subjects (3.4 ± 0.7 nmol · 1−1 · h−1, P< 0.05), but the total renin concentration and immunoreactive total renin concentrations in the two groups were not significantly different. These results indicate that the total renin content of the plasma does not change, whereas the active renin content decreases with age in normal subjects, and suggest that activation of prorenin to active renin may be impaired in elderly subjects.

Frequency of gastroesophageal reflux events induced by pharyngeal water stimulation in young and elderly subjects

1997 ◽  
Vol 272 (2) ◽  
pp. G233-G237 ◽  
Author(s):  
P. Xie ◽  
J. Ren ◽  
E. Bardan ◽  
R. K. Mittal ◽  
Z. Sui ◽  
...  
Keyword(s):  
Gastroesophageal Reflux ◽  
Lower Esophageal Sphincter ◽  
Abdominal Segment ◽  
The Elderly ◽  
Elderly Subjects ◽  
Postprandial Period ◽  
Esophageal Sphincter ◽  
Young Subjects ◽  
Young And Elderly Subjects

Earlier studies have shown that isolated complete lower esophageal sphincter (LES) relaxation occurs as a result of pharyngeal water stimulation. Association of these relaxations with gastroesophageal reflux has not been studied systematically. Our aim was to determine this association in young and elderly subjects during precibal and postprandial periods. We studied 8 young subjects and 10 elderly subjects for 1 h before and 2 h after a 1,000-cal meal. In both groups, during the precibal period, negligible LES relaxation induced by pharyngeal water stimulation resulted in gastroesophageal reflux. In the postprandial period, gastroesophageal reflux events occurred after 16% of pharyngeal water injections in young subjects and after 44% in elderly subjects (P < 0.05). Intraabdominal length of the LES in elderly subjects was significantly shorter compared with younger subjects (P < 0.05). We conclude that gastroesophageal reflux events induced by pharyngeal water stimulation in the postprandial period are significantly increased compared with those of the precibal period and are significantly more prevalent in the elderly compared with the young. These differences seem to be associated with a significantly shorter intra-abdominal segment of the LES in the elderly.

Postprandial decrease in vascular resistance correlated with change in second derivative of finger plethysmogram in young subjects

VASA ◽  
2015 ◽  
Vol 44 (1) ◽  
pp. 43-48
Author(s):  
Kunihiko Tanaka ◽  
Kimiko Kamihira ◽  
Fumie Minoura ◽  
Miyuki Watanabe ◽  
Emi Fujiyoshi ◽  
...  
Keyword(s):  
Peripheral Resistance ◽  
The Elderly ◽  
Elderly Subjects ◽  
Second Derivative ◽  
Hypertension Treatment ◽  
Treatment Of Hypertension ◽  
Before And After ◽  
Young Subjects ◽  
Meal Ingestion ◽  
Young And Elderly Subjects

Background: The second derivative of the finger plethysmogram (SDPTG) comprises five waves termed a to e. The magnitudes of waves b-e are normalized by that of wave a for within- and between-patient comparison. In the present study, affects of meal ingestion for SDPTG in young and elderly subjects are examined. Subjects and methods: Mean arterial pressure and SDPTG before and after meal ingestion in young and elderly subjects were measured. For young subjects, stroke volume and pulse rate were also measured, and the total peripheral resistance (TPR) of the blood vessels was analyzed. Relationship between TPR and the ratio of the peak of SDPTG in young subjects was also analyzed. Results: In young subjects, postprandial d/a was significantly larger and TPR was smaller than before intake and was linearly and significantly correlated with TPR. An increase in the postprandial d/a was also observed in the elderly subjects who were not undergoing hypertension treatment. However, this increase was not observed in elderly subjects who were treated for hypertension. Conclusions: Change in d/a is considered to be an index of change in TPR. TPR is considered to be decreased by agents for treatment of hypertension, and meal ingestion does not appear to further decrease TPR. These results are considered to be useful for understanding cardiodynamics surrounding meal ingestion.

Estimating Audiometric Thresholds Using Auditory Steady-State Responses

2005 ◽  
Vol 16 (03) ◽  
pp. 140-156 ◽  
Author(s):  
Terence W. Picton ◽  
Andrew Dimitrijevic ◽  
Maria-Cecilia Perez-Abalo ◽  
Patricia Van Roon
Keyword(s):  
Steady State ◽  
Normal Subjects ◽  
Hearing Impaired ◽  
Elderly Subjects ◽  
Recording Time ◽  
Steady State Responses ◽  
Young Subjects ◽  
Auditory Steady State Responses ◽  
Intensity Functions ◽  
State Responses

Human auditory steady-state responses (ASSRs) were recorded using stimulus rates of 78–95 Hz in normal young subjects, in elderly subjects with relatively normal hearing, and in elderly subjects with sensorineural hearing impairment. Amplitude-intensity functions calculated relative to actual sensory thresholds (sensation level or SL) showed that amplitudes increased as stimulus intensity increased. In the hearing-impaired subjects this increase was more rapid at intensities just above threshold ("electrophysiological recruitment") than at higher intensities where the increase was similar to that seen in normal subjects. The thresholds in dB SL for recognizing an ASSR and the intersubject variability of these thresholds decreased with increasing recording time and were lower in the hearing impaired compared to the normal subjects. After 9.8 minutes of recording, the average ASSR thresholds (and standard deviations) were 12.6 ± 8.7 in the normal subjects, 12.4 ± 11.9 dB in the normal elderly, and 3.6 ± 13.5 dB SL in the hearing-impaired subjects.

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