Transcranial magnetic stimulation in Alzheimer disease: motor cortex excitability and cognitive severity.

To study the possible changes of cortical excitability in the Alzheimer disease (AD) by transcranial magnetic stimulation (TMS) and to evaluate their eventual correlation with its stage twenty-one AD patients and 18 normal controls underwent TMS. Motor threshold, amplitudes of motor evoked potentials (MEPs), central motor conduction time (CMCT) and silent period (SP) were considered. The motor threshold in AD patients was lower than in normal subjects with a significant correlation between the stage of cognitive severity. The amplitude of MEPs was increased and the SP duration was reduced in AD patients. No significant differences were obtained for CMCT. These findings could suggest a correlation between increased motor cortical excitability and cognitive severity. Moreover, the increased cortical excitability could represent a key to understand the mechanism of AD and may have implication for novel treatment strategies.

Spectral analysis of 24 h blood pressure monitoring in the assessment of trough: peak ratio. A randomized, placebo-controlled, cross-over comparison of ramipril and enalapril.

BACKGROUND: The ratio between the magnitude of blood pressure reduction during the steady-state dosage interval (trough) and the maximum blood pressure reduction (peak) is an integrated in-vivo index both of the pharmacokinetic properties and of pharmacodynamic activity of an antihypertensive drug. Angiotensin converting enzyme inhibitors are often characterized by a low (often lower than 50%) trough: peak ratio but no direct drug comparisons are available. OBJECTIVE: To compare the absolute blood pressure reduction and the trough: peak ratio of daily doses of two angiotensin converting enzyme inhibitors, 5 mg ramipril and 10 mg enalapril. METHOD: After a 1-month wash-out and a 2-week placebo run-in, 25 mild hypertensives aged 47 +/- 4 years (17 men and eight women) were randomly assigned to treatments separated by a 2-week interval. Ambulatory blood pressure monitoring was performed and trough: peak ratio was calculated by the fast Fourier transform analysis of placebo-effect-subtracted data. RESULTS: After 1 month of ramipril treatment, 24 h blood pressure decreased from 139 +/- 10 to 129 +/- 11 mmHg for systolic (P < 0.05) and from 89 +/- 8 to 81 +/- 5 mmHg for diastolic blood pressure (P < 0.01). Also enalapril treatment caused a significant 24 h reduction in blood pressure both for systolic (to 132 +/- 7 mmHg, P < 0.05) and for diastolic blood pressure (to 84 +/- 5 mmHg, P < 0.05). Placebo caused a 24 h reduction in blood pressure (to 136 +/- 8 mmHg for systolic and 87 +/- 5 mmHg for diastolic blood pressure, NS, versus wash-out period). The two drugs were equally effective in reducing ambulatory blood pressure, but ramipril produced a trough: peak ratio significantly higher than that with enalapril both for systolic (48 +/- 11%, range 34-74%, versus 38 +/- 11%, range 21-67%, P < 0.005)and for diastolic blood pressure (47 +/- 11%, range 30-79 %, versus 37 +/- 12%, range 21-68%, P < 0.05). CONCLUSION: The low trough : peak ratios could have been due to the daily pattern of blood pressure of mild hypertensives, many of whom are normotensives at night-time, so that the main antihypertensive effect is exerted during daytime rather than during the night or early morning.

Clinical evaluation of the QuietTrak blood pressure recorder according to the protocol of the British Hypertension Society.

METHODS: The QuietTrak ambulatory blood pressure recorder (Tycos-Welch-Allyn, Arden, North Carolina, USA) was evaluated according to the protocol of the British Hypertension Society (BHS). QuietTrak, a lightweight (355 g), automatic, programmable device, uses an auscultatory measuring system. The protocol of the BHS was composed of subsequent phases with QuietTrak and two observers taking simultaneous measurements on the same arm. RESULTS: No interdevice differences were observed at analysis of variance test either before or after a 1-month period of routine clinical use. The average difference between mercury sphygmomanometer and QuietTrak for systolic and diastolic blood pressures was -0.6+/-3.6 and -0.4+/- 3.6 mmHg before and -0.7+/- 3.3 mmHg and 0.6+/- 3.8 mmHg after the 1-month use. At the main static device validation procedure, performed in 85 subjects, the average difference between observers and QuietTrak was -0.3+/- 3.4 and 0.1+/- 3.5 mmHg for systolic and diastolic blood pressures. Eighty-nine per cent and 99% of systolic and 88% and 98% of diastolic QuietTrak readings were within 5 and 10 mmHg of obsevers, determinations (Class A). In children (n = 33) 87% of systolic and 90% of diastolic QuietTrak readings differed by less than 5 mmHg from the observers' readings (average difference -1.1+/-3.9 and 0.1+/- 3.6 mmHg, respectively). In the elderly (n = 30), 95% and 92% of systolic and diastolic readings were within 5 mmHg of mercury column determinations (average difference -0.8+/-3.2 and -0.2+/-4.5 mmHg). In pregnancy (n = 30), 93% of systolic and 100% of diastolic readings were within 5 mmHg of mercury column determination (average difference -0.3+/-3.4 and 0.1+/- 2.9 mmHg). Device reliability was not affected by posture. Ninety-six per cent and 89% of systolic and diastolic readings differed by less than 5 mmHg from the mercury column determinations in the supine position, 90% and 90% in the standing position, and 88% and 90% in the sitting position. During the treadmill exercise (Bruce protocol), 69% and 88% of systolic and 56% and 83% of diastolic QuietTrak readings differed by less than 5 and 10 mmHg from the observers' measurements. CONCLUSION: The QuietTrak achieved A rating for systolic blood pressure and A rating for diastolic blood pressure according to the criteria of the BHS protocol. The device was acceptable to patients because of its small size, light weight and noiseless performance.