Effect of oral glucocorticoid intake on autonomic cardiovascular control.

This study analyzed baroreflex sensitivity, heart rate and systolic blood pressure variabilities during an oral 1 week administration of prednisone. This study examined the hypothesis that prednisone might change both systolic blood pressure level and baroreflex sensitivity. Twelve physically active male subjects participated to a double-blind, randomized cross-over study consisting of two 1-week periods of treatment separated by a 4-week drug-free washout period: placebo (PLA) or prednisone (PRED). Trials were performed by each subject four times on the second (D2) and seventh (D7) day of each treatment period. ECG and blood pressure were continuously recorded to compute heart rate variability, systolic blood pressure variability and baroreflex sensitivity components with the smoothed pseudo Wigner Ville distribution and baroreflex analysis. Following D2 prednisone treatment, both HR (PLA: 60.8 ± 10.5 vs. PRED: 65.8 ± 9.1 beats min(-1), p = 0.008) and low frequency component of systolic blood pressure variability (D2: 3.09 ± 0.19 vs. D7: 2.34 ± 0.19, p < 0.041) increased whereas other components did not change. Over 7 days of treatment, LF-SBP amplitude increased (D2: 2.71 ± 0.89 vs. D7: 3.87 ± 0.6 mmHg, p = 0.037). A slight increase in both HR and LF-SBPV were observed suggesting a potential sympathetic cardiovascular stimulus. Although we found a significant effect of the 1-week prednisone treatment on heart rate and low frequency power of systolic blood pressure variability, we reported neither an increase in the systolic blood pressure level nor a decrease in the baroreflex sensitivity. Therefore, the fragility of our results cannot support a deleterious effect of 1-week administration of prednisone on the autonomic cardiovascular control which might be involved in cardiovascular diseases.

Effect of "Touch Rugby" Training on the Cardiovascular Autonomic Control In Sedentary Subjects.

This study aimed to explore the effects of "touch-rugby" training on the cardiovascular autonomic control in sedentary subjects. 22 adults (30-64 years old) were included in this study. Before (pre-test) and after (post-test) the period of training, cardio-respiratory recordings were achieved at rest and during a graded maximal exercise on a treadmill. The Smoothed-Pseudo-Wigner-Ville Distribution provided instantaneous time frequency components of RR intervals and systolic blood pressure variability in low- and high-frequency bands. The baroreflex sensitivity was assessed in low-frequency and high-frequency bands. Between pre-test and post-test, resting heart rate (74±10 vs. 69±12 beats.min(-1), p<0.05) and systolic blood pressure (118±19 vs. 103±22 mm Hg, p<0.01) decreased. Root mean square of successive differences (34.6±30.1 vs. 47.6±34.8 ms, p<0.001), high-frequency RR variability (590±288 vs. 1262±767 ms², p<0.001) increased whereas low-frequency/high-frequency ratio decreased (3.5±3.4 vs. 1.5±0.9, p<0.05). The high-frequency baroreflex sensitivity increased (13.4±10.1 vs. 26.0±20.9 ms.mmHg(-1), p<0.05). Playing touch rugby with one session weekly over 3 months modified the cardiovascular autonomic control of sedentary subjects. A decrease in the sympathetic tone combined with both an increase in the vagal tone and a decrease in systolic blood pressure at rest were observed. Therefore, such training appears to be beneficial to cardiac health.

Improved tolerance of peripheral fatigue by the central nervous system after endurance training.

PURPOSE: The purposes of this study were to evaluate the effect of endurance training on central fatigue development and recovery. METHODS: A control group was compared to a training group, which followed an 8-week endurance-training program, consisting in low-force concentric and isometric contractions. Before (PRE) and after (POST) the training period, neuromuscular function of the knee extensor (KE) muscles was evaluated before, immediately after and during 33 min after an exhausting submaximal isometric task at 15 % of the maximal voluntary contraction (MVC) force. After training, the trained group performed another test at iso-time, i.e., with the task maintained until the duration completed before training was matched (POST2). The evaluation of neuromuscular function consisted in the determination of the voluntary activation level during MVCs, from peripheral nerve electrical (VAPNS) and transcranial magnetic stimulations (VATMS). The amplitude of the potentiated twitch (Pt), the evoked [motor evoked potentials, cortical silent period (CSP)] and voluntary EMG activities were also recorded on the KE muscles. RESULTS: Before training, the isometric task induced significant reductions of VAPNS, VATMS and Pt, and an increased CSP. The training period induced a threefold increase of exercise duration, delayed central fatigue appearance, as illustrated by the absence of modification of VAPNS, VATMS and CSP after POST2. At POST, central fatigue magnitude and recovery were not modified but Pt reduction was greater. CONCLUSION: These results suggest that central fatigue partially adapts to endurance training. This adaptation principally translates into improved tolerance of peripheral fatigue by the central nervous system.

Time-course of prednisone effects on hormonal and inflammatory responses at rest and during resistance exercise.

Glucocorticoids are among the most commonly used drugs. They are widely administered for acute and chronic musculoskeletal pain, as well as for several other pain syndromes, although their therapeutic use is sometimes diverted for doping purposes. Their time-course effects on hormonal and inflammatory responses nevertheless remain poorly understood, both at rest and during exercise. We therefore studied the alterations induced by 1 week of prednisone treatment (60 mg daily) in recreationally trained male athletes after 2 days (i. e., acute) and 7 days (i. e., short-term). Hormonal (i. e., DHEA, DHEA-S, aldosterone, and testosterone) and pro- and anti-inflammatory markers (i. e., IL-6, IL-10, and IL-1ß) were investigated at rest and after resistance exercise. A significant decrease in DHEA and DHEA-S (p<0.01) without change in the DHEA/DHEA-S ratio, aldosterone, or testosterone was demonstrated after acute prednisone intake. A significant increment in IL-10 and a significant decrement in IL-6 (p<0.05) were also observed with prednisone both at rest and during exercise, without significant change in IL-1ß. Continued prednisone treatment led to another significant decrease in both DHEA and DHEA-S (p<0.05), whereas no change in the inflammatory markers was observed between days 2 and 7. Our data demonstrate that the anti-inflammatory effects of prednisone were maximal and stable from the beginning of treatment, both in rest and exercise conditions. However, hormonal concentrations continued to decline during short-term intake. Further studies are needed to determine the effects of hormonal time-course alterations with longer glucocorticoid treatment and the clinical consequences.

GC-MS analysis of cuticular lipids in recent and older scavenger insect puparia. An approach to estimate the postmortem interval (PMI).

An analytical method was developed to characterize puparia cuticular lipids (hydrocarbons, waxes) and to compare the molecular distribution patterns in the extracts from either recent or older puparia. Acid-catalyzed transesterification and solvent extraction and purification, followed by combined gas chromatography coupled to mass spectrometry, were optimized for the determination of hydrocarbons and fatty acid ethyl esters from transesterified waxes, extracted from a single species of a fly scavenger (Hydrotaea aenescens Wiedemann, 1830). Comparison between recent (2012) or older (1997) puparia contents has highlighted significant composition differences, in particular, a general decrease of the chain length in the n-alkane distribution pattern and, on the contrary, an increase of the ester chain length. Both extracts contain traces of three hopane hydrocarbon congeners. Preliminary results evidence the change in puparia lipid composition over time, thus potentially providing new indices for estimating postmortem interval.

Therapeutic glucocorticoid administration alters the diurnal pattern of dehydroepiandrosterone.

Significant alteration in hypothalamic-pituitary-adrenal function has been demonstrated in patients after short-term glucocorticoid therapy, but its impact on the circadian rhythm of steroid hormones has never been investigated. This study examined the effects of short-term prednisone administration on the diurnal patterns of dehydroepiandrosterone (DHEA) and testosterone. Saliva samples were collected from 11 healthy, physically active, male volunteers for DHEA and testosterone analysis, as follows: every 4 h from 0800 to 2000 h on 2 control days without medication, and after 1 week of oral therapeutic prednisone treatment (60 mg daily) (days 0-3). Overall, a diurnal decline in the two steroid hormones was observed on the control days. After short-term glucocorticoid administration, DHEA concentrations were significantly decreased with a complete disappearance of the DHEA diurnal pattern, which lasted 2 days post-treatment. No glucocorticoid effect was observed for testosterone. The results indicate that short-term prednisone treatment affects the circadian pattern of saliva DHEA but not testosterone in healthy active volunteers. Further studies are necessary to determine whether this alteration in DHEA circadian pattern has clinical consequences in patients with chronic glucocorticoid therapy.

Effects of endurance training on the maximal voluntary activation level of the knee extensor muscles.

PURPOSE: The aim of this study was to investigate the neural adaptations to endurance training, and more specifically the adaptation of the cortical voluntary activation of the knee extensor (KE) muscles. METHODS: Sixteen sedentary men were randomly allocated into an endurance training (n = 8) or a control group (n = 8). All subjects performed a maximal aerobic speed test (MAS) before and immediately after the training period. Training lasted 8 weeks and was based on endurance running. During Pre- and Post-training testing sessions, maximal voluntary contraction (MVC) was measured and voluntary activation (VA) was calculated via peripheral nerve (PNS) and transcranial magnetic stimulations (TMS) superimposed to MVC. Electromyographic activity (EMG) of the KE muscles was also measured during MVC, PNS (M-wave) and TMS (motor evoked potentials-MEP). The cortical silent period following TMS was also assessed. RESULTS: Despite a significant improvement in endurance running performance, as suggested by the increase of MAS in the training group (Pre 15.4 ± 1.6 vs. Post 16.4 ± 1.6 km·h(-1)), endurance training did not affect MVC or VA as measured with PNS and TMS. Similarly, the EMG of KE muscles during MVC did not show any significant changes. Furthermore, the MEP amplitude and the duration of the silent period also remained unchanged after endurance training. CONCLUSIONS: The present study suggests an 8-week endurance-training program does not generate adaptations of neural factors in sedentary subjects.

Oxygen consumption and gait variables of Arabian endurance horses measured during a field exercise test.

REASONS FOR PERFORMING STUDY: Arabian horses have morphological, muscular and metabolic features designed for endurance races. Their gas exchange and gait variables were therefore measured during a field exercise test. This study presents original respiratory and locomotor data recorded in endurance horses under field conditions. HYPOTHESIS AND OBJECTIVES: Respiratory gas exchange ratio (RER) of Arabian horses at the speed required to win endurance races (18 km/h for 120-160 km) are <1 and running economy (RE) is also low in order to maintain exercise intensity using aerobic metabolism for long intervals. The purpose of this study was to measure oxygen consumption and gait variables in Arabian endurance horses running in the field in order to estimate RER and RE. MATERIALS AND METHODS: Five Arabian horses trained for endurance racing were test ridden at increasing speeds on the field. Their speed was recorded and controlled by the rider using a GPS logger. Each horse was equipped with a portable respiratory gas analyser, which measured breath-by-breath respiratory variables and heart rate. The gait variables were recorded using tri-axial accelerometer data loggers and software for gait analysis. Descriptive statistics and linear regressions were used to analyse the speed related changes in each variable with P < 0.05 taken as significant. RESULTS: At a canter speed corresponding to endurance race winning speed (18 km/h), horses presented a VO(2) = 42 ± 9 ml/min/kg bwt, RER = 0.96 ± 0.10 and RE (= VO(2) /speed) = 134 ± 27 l/km/kg bwt. Linear relationships were observed between speed and VO(2,) HR and gait variables. Significant correlations were observed between VO(2) and gait variables. CONCLUSIONS AND POTENTIAL RELEVANCE: The RER of 0.96 at winning endurance speed indicates that Arabian horses mainly use aerobic metabolism based on lipid oxidation and that RER may also be related to a good coordination between running speed, respiratory and gait parameters.

Relationship between ventilatory thresholds and systolic blood pressure variability.

During exercise, an increase in respiratory rate amplifies the blood pressure oscillations. This phenomenon is usually intensified when exercise rate exceeds the ventilatory thresholds (VTs). The present study examined whether VTs assessment was possible from systolic blood pressure variability (SBPV) analysis to give blood pressure ventilatory thresholds (BPVTs). Blood pressure, ECG, and Ventilatory equivalents (VE/VO2, VE/VCO2) were collected from 15 well-trained subjects during an incremental exhaustive test performed on a cycloergometer. The "Short-Time Fourier Transform" was applied to SBP series to compute the instantaneous high frequency SBPV power (HF-SBPV). BPVTs were determined in all but 3 subjects. For the 12 remaining subjects, visual examination of ventilatory equivalents and HF-SBPV power revealed 2 thresholds for both methods. There was no difference between the first (VT1 235+/-60 vs. BPVT1 226+/-55 W, p=0.063) and second (VT2 293+/-67 vs. BPVT2 301+/-66 W, p=0.063) thresholds. However, BPVT1 was slightly underestimated compared to VT1 (9.9+/-15.4 W) given lower limit of agreement (LOA) at -19.9 W and higher at 40.4 W. BPVT2 was over-estimated compared to VT2 (-8.8+/-11.2 W) given lower LOA at -30.9 W and higher at 13.4 W. Thus, BPVTs determination appears useful in conditioning programs with sedentary or pathological subjects but probably not with trained subjects.

Ventilatory thresholds assessment from heart rate variability during an incremental exhaustive running test.

The present study examined whether the ventilatory thresholds during an incremental exhaustive running test could be determined using heart rate variability (HRV) analysis. Beat-to-beat RR interval, V(.-)O (2), V(.-)CO (2) and V(.-) (E) of twelve professional soccer players were collected during an incremental test performed on a track until exhaustion. The "smoothed pseudo Wigner-Ville distribution" (SPWVD) time-frequency analysis method was applied to the RR time series to compute the usual HRV components vs. running speed stages. The ventilatory equivalent method was used to assess the ventilatory thresholds (VT1 and VT2) from respiratory components. In addition, ventilatory thresholds were assessed from the instantaneous components of respiratory sinus arrhythmia (RSA) by two different methods: 1) from the high frequency peak of HRV ( FHF), and 2) from the product of the spectral power contained within the high frequency band (0.15 Hz to fmax) by FHF (HF x FHF) giving two thresholds: HFT1 and HFT2. Since the relationship between FHF and running speed was linear for all subjects, the VTs could not be determined from FHF. No significant differences were found between respective running speeds at VT1 vs. HFT1 (9.83 +/- 1.12 vs. 10.08 +/- 1.29 km x h (-1), n.s.) nor between the respective running speeds at VT2 vs. HFT2 (12.55 +/- 1.31 vs. 12.58 +/- 1.33 km x h (-1), n.s.). Linear regression analysis showed a strong correlation between VT1 vs. HFT1 (R (2) = 0.94, p < 0.001) and VT2 vs. HFT2 (R (2) = 0.96, p < 0.001). The Bland-Altman plot analysis reveals that the assessment from RSA gives an accurate estimation of the VTs, with HF x FHF providing a reliable index for the ventilatory thresholds detection. This study has shown that VTs could be assessed during an incremental running test performed on a track using a simple beat-to-beat heart rate monitor, which is less expensive and complex than the classical respiratory measurement devices.

Assessment of ventilatory thresholds from heart rate variability in well-trained subjects during cycling.

The purpose of this study was to implement a new method for assessing the ventilatory thresholds from heart rate variability (HRV) analysis. ECG, VO2, VCO2, and VE were collected from eleven well-trained subjects during an incremental exhaustive test performed on a cycle ergometer. The "Short-Term Fourier Transform" analysis was applied to RR time series to compute the high frequency HRV energy (HF, frequency range: 0.15 - 2 Hz) and HF frequency peak (fHF) vs. power stages. For all subjects, visual examination of ventilatory equivalents, fHF, and instantaneous HF energy multiplied by fHF (HF.fHF) showed two nonlinear increases. The first nonlinear increase corresponded to the first ventilatory threshold (VT1) and was associated with the first HF threshold (T(RSA1) from fHF and HFT1 from HF.fHF detection). The second nonlinear increase represented the second ventilatory threshold (VT2) and was associated with the second HF threshold (T(RSA2) from fHF and HFT2 from HF.fHF detection). HFT1 , T(RSA1), HFT2, and T(RSA2) were, respectively, not significantly different from VT1 (VT1 = 219 +/- 45 vs. HFT1 = 220 +/- 48 W, p = 0.975; VT1 vs. T(RSA1) = 213 +/- 56 W, p = 0.662) and VT2 (VT2 = 293 +/- 45 vs. HFT2 = 294 +/- - 48 W, p = 0.956; vs. T(RSA2) = 300 +/- 58 W, p = 0.445). In addition, when expressed as a function of power, HFT1, T(RSA1), HFT2, and T(RSA2) were respectively correlated with VT1 (with HFT1 r2 = 0.94, p < 0.001; with T(RSA1) r2 = 0.48, p < 0.05) and VT2 (with HFT2 r2 = 0.97, p < 0.001; with T(RSA2 )r2 = 0.79, p < 0.001). This study confirms that ventilatory thresholds can be determined from RR time series using HRV time-frequency analysis in healthy well-trained subjects. In addition it shows that HF.fHF provides a more reliable and accurate index than fHF alone for this assessment.

Effect of repeated exercise and recovery on heart rate variability in elite trotting horses during high intensity interval training.

REASONS FOR PERFORMING STUDY: Interval training is a commonly used training method for trotting horses. In addition, trainers are provided with efficient and inexpensive heart rate monitor devices for the management of training. HYPOTHESIS: Since the high frequency (HF) frequency peak (fHF) of heart rate variability (HRV) corresponds to the breathing frequency in combination with stride frequency during trotting, it is hypothesised that modifications of breathing and stride frequencies induced by repeated exercise could be detected from fHF. METHODS: RR interval time series of 7 trotting horses were recorded during an interval training session. Interval training was made up of 5 successive 800 m high-velocity trotting runs (H1, H2...H5) separated by 1 min recovery bouts at low speed (R1, R2...R5). Fast Fourier transform (FFT) and Poincaré plot analysis techniques were applied to RR series. RESULTS: Repeated exercise had significant effects on HRV components during interval training. Despite constant trotting velocities during high-speed and recovery, repetition induced a decrease in mean RR interval (H1: 295 +/- 19 vs. H5: 283 +/- 15 msec, P<0.05) and in the root mean square of successive differences in RR series (RMSSD; H1: 6.31 +/- 1.28 vs. H5: 5.31 +/- 1.31 msec, P<0.05). Furthermore, high-speed and recovery repetitions induced an increase in fHF (H1: 1.37 +/- 0.35 vs. H5: 1.62 +/- 0.40 Hz and R1: 0.22 +/- 0.02 vs. R4: 0.64 +/- 0.38 Hz, P<0.05). Hence, recovery induced a decrease in the s.d. of the successive RR series (SDRR; R3: 10.5 +/- 3.96 vs. R5: 6.17 +/- 2.65 msecs, P>0.05) and in the long term index of Poincaré plot (SD2; R1: 43.29 +/- 28.90 vs. R5: 18.19 +/- 9.35 msecs, P<0.05). CONCLUSIONS: The observed increase in fHF during the interval training could be induced by alterations of the coupling between breathing and stride frequency linked to the emergence of fatigue. The decrease in SD2 and SDRR during successive recovery bouts could be linked with a deterioration of the recovery pattern. POTENTIAL RELEVANCE: HRV can provide breathing frequency data of Standardbreds during training without any respiratory device. Furthermore, HRV could provide useful makers of the emergence of fatigue states during training.

Effect of exercise intensity and repetition on heart rate variability during training in elite trotting horse.

RR intervals of ten elite trotting horses were recorded during an interval training session performed on track. This study examined two hypotheses. Firstly, like in humans, the hyperpnea combined with a decrease in cardiac autonomic control on heart rate during heavy exercise could result in a prevalence of high frequency heart rate variability. Secondly, this prevalence could increase with the heavy exercise repetition. Two exercise intensities were compared: moderate (ME) and heavy (HE). Furthermore, heavy exercise repetitions were compared between the beginning and the end of the interval training session. When comparing ME and HE periods: heart rate was significantly lower (155 +/- 12 vs. 210 +/- 9 ms, p < 0.001), LF spectral energy (0.04 - 0.2 Hz) was significantly higher (ME: 6.94 +/- 4.80 and HE: 0.24 +/- 0.14 ms(2) . Hz (-1), p < 0.001) whereas HF (0.2 - 2 Hz) was significantly lower (ME: 7.09 +/- 2.24 and HE: 10.60 +/- 3.64 ms(2) . Hz (-1), p < 0.05). In relative terms, ME showed similar results in both LFn (LF/LF+HF) and HFn (HF/LF+HF) whereas HE showed a large prevalence of HFn energy compared to LFn (p < 0.001). The difference in LF/HF ratio between the two exercise conditions was significant (1.14 +/- 0.92 vs. 0.09 +/- 0.12, p < 0.001). Exercise repetition induced a significant increase in heart rate between the beginning and the end of the interval training session (207 +/- 10 beats . min (-1) vs. 212 +/- 9 beats . min (-1), p < 0.001) whereas LF energy decreases (1.54 +/- 1.65 vs. 0.32 +/- 0.24 ms(2) . Hz (-1), p < 0.01) and HF energy remained constant (10.79 +/- 4.10 vs. 10.40 +/- 3.35 ms(2) . Hz (-1), NS). This study confirmed the results observed in humans during heavy exercise conditions with a large prevalence of HF in contrast to LF, this prevalence increasing with exercise repetitions. The observed decrease in LF/HF ratio could provide an index of hyperpnea in horses during interval training.

Effects of exercise load and breathing frequency on heart rate and blood pressure variability during dynamic exercise.

It is known that heart rate (HR) variability decreases with dynamic exercise, but there are only few studies on blood pressure (BP) variability with exercise loads and the effect of breathing pattern has never been investigated. Thus, we studied HR and systolic blood pressure (SBP) signals by spectral analysis (FFT), in 9 healthy subjects, at different breathing frequencies (0.15, 0.2, 0.3, 0.4, 0.5, 0.6 Hz), at rest and during 3 exercise loads (25, 50 and 75% VO2max). BP was measured with a non-invasive device (Finapres) and continuously recorded. The power spectrum of R-R period significantly decreased with exercise loads in the low frequency band (LF: 0.04-0.128 Hz) and in the high frequency band (HF: 0.128-0.65 Hz), but with breathing frequency only in the HF part of the spectrum. The power spectrum of SBP significantly increased with exercise loads in LF and HF bands, and decreased in HF band with increasing breathing frequency. R-R and SBP HF peaks were centered on breathing frequency peaks. Therefore, spectral analysis of HR and SBP confirm the withdrawal of vagal control during exercise, while mechanical effect of respiration on SBP persists. LF/HF ratio of R-R spectral components decreased with increasing load, whereas cardiovascular sympathetic activity is known to rise, suggesting that this ratio is not a good indicator of cardiovascular autonomic modulation during exercise.

Errors in distance appreciation and binocular night vision.

Studying binocular vergence in relation to luminance levels, we isolated two types of behaviour which may explain differences in distance appreciation: 1. Underestimation of distances in subjects with overconvergence in darkness. 2. Overestimation of distances in subjects with underconvergence in darkness. Progression towards the limiting value of convergence varies from one individual to another for each mesopic and scotopic luminance level and for different experimental conditions: variable discrepancy between the observation distance and the tonic vergence distance; accommodative or fusional stimuli at varying degrees of eccentricity; mobile stimuli in the observer's peripheral field. The study of bipartition in depth of a given interval for different observation distances confirms the existence of two major categories of individuals. Over- or underestimation of the nearer subjective half correlates to the binocular dark convergence capacity of each individual. These findings may explain errors in distance appreciation for road users in night vision.

[Binocular functional exploration: fundamental aspects and analysis by the Fusio-Test]. / Exploration fonctionnelle binoculaire: aspects fondamentaux et analyse par le Fusio-Test.

After reviewing psychophysical and neurophysiological data concerning disparity processing and stereoscopic depth perception, as well as the limits of variation in perceived depth and fusion in function of binocular disparity, a new computer controlled apparatus named Fusio-Test is presented for functional binocular exploration. A battery of stereograms available in the test library made it possible to study in particular depth perception or stereoacuity, aniseikonia and fixation disparity, using the most suitable preprogrammed psychophysical procedure such as the limit method, constant stimuli, Cornsweet's psychophysical staircase, and one alternative forced choice method or multiple choice method. The test selected for each phase of the binocular examination was presented in polarized light on two Video Units. The required measurements were displayed on a small terminal and occasionally the data variations were recorded in real time. For the control of depth perception and the evaluation of stereoscopic acuity, two types of tests were programmed: line stereograms made of series of vertical lines varying in number and relative spacing or stylized shapes, random dot stereograms with different cyclopean shapes (circle, square, triangle or scaled pyramid), some of them with reduced binocular correlation according to Julesz. The originality of this apparatus for aniseikonia lies in its use of a battery of Ogle's spatial test stereograms, having incorporated vertical and horizontal magnifications ranging from 0 to 15% by 1% increments. The measurements were obtained by trying to find the pair of stereograms that must be presented to the right and the left eyes in order to eliminate the perceived distorsions (geometric or induced effect) and to recover the normal classical configuration of the spatial test. The test for fixation disparity was comprised of the Ogle arrangement with two polarized vertical lines forming a binocular nonius in the middle of a field surrounded with letters to stimulate fusion. Data for a sample of observers wearing glasses, contact lenses or implants, are presented and analyzed, bringing to light certain anomalies in binocular disparity processing. Differences in stereoacuity are noted: partial or total stereoblindness depending on the test selected (line stereograms or random dot stereograms, crossed or uncrossed disparities), on the spacing of the test elements; variations of threshold in time.(ABSTRACT TRUNCATED AT 400 WORDS)

[Study of spatial function using the contrast sensitivity function. Cases of presbyopic subjects fitted with progressive glasses]. / Exploration fonctionnelle spatiale par la fonction de sensibilité au contraste. Cas de sujets presbytes équipés de verres progressifs.

The spatial properties of the global visual system were measured on the basis of the contrast sensitivity function, in three presbyopic observers. Shape alterations of the contrast sensitivity curves were found depending on the experimental conditions: foveal vision, in far, intermediary and near vision, along central, 13 degrees nasal and 13 degrees temporal meridians (according to three parallels and three meridians), peripheral vision, in far and near vision, at 13 degrees and 26 degrees retinal eccentricities using the central or nasal part of the lens. The central meridian was found to be the most efficient part of the progressive lenses. These results strengthen the observations reported by ophthalmologists and progressive lens wearers.

[New stereoprojector with polarized tests, for exploration of aniseikonia and the perception of relief]. / "Nouveau stéréoprojecteur avec tests polarisés, destiné à l'exploration de l'aniséiconie et du sens du relief".

We describe a stereoprojector in polarized light built at the Laboratory of Physics, Museum (Paris) with a battery of stereograms specially designed for the two following aspects of binocular vision examination. a) Determination of Aniseikonia from 0 to 15% with both the direct comparison target and the spatial cikonic target. b) Studies on stereopsis in focal and peripheral vision, using tests for local stereopsis with disparities going from 0 to 350" by steps of 15", or some kinds of Random Dot stereograms of Julesz.