G. Spinatonda’s research while affiliated with Istituti Clinici Scientifici Maugeri IRCCS and other places

Baroreflex sensitivity assessed by means of the phenylephrine test plays a prognostic role in patients with previous myocardial infarction, but the need for drug injection limits the use of this technique. Recently, several non-invasive methods based on spectral analysis of systolic arterial pressure and heart period have been proposed, but their agreement with the phenylephrine test has not been investigated in patients with heart failure. The two methods (phenylephrine test and spectral analysis) were compared in a group of 49 patients with chronic congestive heart failure both at rest and during controlled breathing. The linear correlation and the limits of agreement between the phenylephrine test slope and the alpha-index [alpha(c); corrected by the coherence function between the interbeat interval (RR interval) and systolic arterial pressure] were evaluated. Only 16 patients had a measurable alpha-index at rest in both the low-frequency (LF) and high-frequency (HF) bands; the alpha(c)-index allowed measurements in all patients. It correlated moderately with the phenylephrine test slope at rest (r=0. 71 and P<0.001 in LF; r=0.57 and P<0.001 in HF) and during controlled breathing (r=0.51 and P<0.001 in LF; r=0.63 and P<0.001 in HF). Multivariate regression analysis showed that only alpha(c)LF during rest and alpha(c)HF during controlled breathing contributed significantly to baroreflex gain estimation. However, the agreement between methods was weak; the normalized limits of agreement and bias were -162 to 243% (0.46 ms/mmHg) for alpha(c)LF and -185 to 151% (-0.99 ms/mmHg) for alpha(c)HF. Thus the comparison between baroreflex sensitivity measurements obtained by the phenylephrine test and spectral analysis showed a moderate correlation between the two methods; however, despite the linear association, a consistent lack of agreement between the two techniques was found. Because both systematic and random factors contribute to the difference, these two techniques cannot be considered as alternatives for the assessment of heart failure.

Spectral analysis of RR interval and systolic arterial pressure variability was applied for the non invasive assessment of the baroreflex gain in Congestive Chronic Heart Failure (CNF). Forty-nine CHF patients were studied during rest, controlled breathing and head-up tilt. The alpha index, a noninvasive measure of the overall gain of the RR to systolic arterial pressure (SAP) relationship, and a modified version called beta, incorporating the weighted coherence function, were computed in the low (LF) and high (NF) frequency bands by spectral analysis, and compared with the phenylephrine test slope. A linear model fitted on the beta index values during rest and controlled breathing showed a high correlation (r=0.93, Standard error of the estimation=2.5 ms/mmHg) with the phenylephrine test slope. In severe CNF patients the beta index proposed, evaluated during rest and controlled breathing, may improve the baroreflex gain estimation and provide a noninvasive assessment method that might be useful in gauging prognosis

The measurement of reaction times in response to suitable stimuli may provide insight into the separate functional blocks corresponding to diverse speech production mechanisms. The quantitative evaluation of speech motor performance provides useful information for the early detection and long-term monitoring of many neurological diseases. The vocal reaction times (VRTs) technique and its application in the assessment of a group of normal subjects is presented. Speech motor performance and the effect of age were investigated by measuring VRTs and speech duration, in a group of thirty normal subjects divided into three age groups (18-44, 45-59, 60-80). VRTs were measured by using an immediate and delayed reaction stimulation paradigm. Analysis of the acoustic and electromyographic signals indicated that reaction times increased with age in both the immediate and delayed tasks; also the acoustic signal durations increased with age. The analysis of variance showed that the difference between the young and elderly groups was statistically significant. This technique may be considered a useful tool to provide qualitative and quantitative measures of the processes involved in speech production.

The aim of this study was to evaluate the effects of chronic exposition to neurotoxic solvents in a group of laundry operators by means of Vocal Reaction Times (VRTs) measurements. A group of normal subjects, matched for age and educational level, constituted the controls. Vocal Reaction Times were measured by a device that presented to each subject a sequence of words on a computer screen, acquired the acoustic signal and measured VRTs and durations. During the test a random sequence of words was presented to the subjects; the protocol consisted of two immediate reading task and two delayed reading tasks. The test was performed using concrete and meaningless words. Statistical analysis showed that reaction times measured on the acoustic signals were longer for the exposed group than for the controls. The differences between durations were significant for the delayed reading tasks using concrete words and for all tasks using meaningless words. These findings suggest that this technique may be considered a useful tool for the assessment of the preclinical alterations of CNS in the monitoring of individuals chronically exposed to neurotoxic solvents.

We studied verbal reactions to visual stimuli in ten subjects with idiopathic Parkinson's Disease (PD) of Hoehn-Yahr stages 1 through 2, untreated, and ten age-matched controls, by means of acousticogram (ACG), surface oromandibular EMG, electrolaryngogram (EGG), and lip and jaw movement recording. Mean reaction times were measured with a device that presented words, acquired the signals and calculated response times and durations. A slight slowing in Verbal Reaction Times (VRTs) was found in the PD group with respect to controls. In two patients we observed two bursts of EMG activity during the responses:an early contraction, and a later burst coinciding approximately with the ACG.

To verify whether the phenylephrine test (PHE) and spectral analysis (alpha-index) provide similar measures of baroreflex sensitivity in patients with chronic heart failure due to left ventricular dysfunction, the authors evaluated by both methods a group of 40 patients during rest and controlled breathing (CB). R-R interval (RR), blood pressure (BP) and respiration were recorded in both conditions (600 heart beats), and bivariate spectral analysis was carried out. The alpha-index was measured when the magnitude squared coherence (MSC) between RR variability and systolic BP variability was >0.5 in the low frequency (αLF) and high frequency (αHF) bands; the mean α was also computed. PHE followed immediately, with at least 3 injections during rest and one during CB. αLF could not be measured during both rest and CB in 40% of patients. The PHE slope could not be found in 7% of patients during rest and in 10% during CB. Regression analysis of the PHE slope vs αLF (r=0.61), α HF (r=0.63) and α(r=0.67) showed a weak correlation during rest. No correlation was found during CB