N. Battistini

Derangement of regional cerebral blood flow and of its regulatory mechanisms in acute cerebrovascular lesions

IT HAS LONG BEEN RECOGNIZED~ that cerebral anoxia produces, in addition to damage to nervous structures, a serious derangement of the mechanisms of regulation of cerebral vasomotility. A more detailed knowledge of the functional aspects of cerebral vascular pathology has been permitted by the availability of reliable methods of exploring quantitatively the circulation in discrete parts of the brain. Studies performed in patients with the radioactive inert gas regional clearance method proposed by Lassen and co-workers in 1963* have demonstrated that [ 11 the autoregulation (constancy of cerebral blood flow at different levels of perfusion pressure) is lost in many patients in the first days after an ischemic insult,”-5 [2] in the same group of patients6 the response to changes in arterial CO, tension may be regionally impaired (loss or delay of cerebral vasodilatation in response to hypercapnia had been previously demonstrated with the N 2 0 method7 and with radioalbumins), and [3] shortly after an acute brain infarction a cerebral reactive hyperemia with marked increase in blood flow (the “luxury perfusion” phenomenon) may occur.5~9,10 Experimental studies have confirmed the above observations,l1-15 whose physiological and possibly practical implications are of considerable importance. The present study further documents the

Recurrence of Bleeding in Patients With Primary Intracerebral Hemorrhage

BACKGROUND AND PURPOSE Rebleeding in patients with primary intracerebral hemorrhage is considered uncommon, but there are no precise data to support this opinion. The purpose of this study was to assess the incidence and predictors of recurrent bleeding in survivors of primary intracerebral hemorrhage. METHODS As part of a prospective study, 112 survivors of a first primary intracerebral hemorrhage were followed up for a mean period of 84.1 months after their discharge. To ascertain risk factors that may influence rebleeding, several demographic, medical history, clinical, and laboratory variables were collected and analyzed. RESULTS Twenty-four percent (27/112) of survivors experienced one or more rebleeding during the follow-up period, in 8 cases (30%) in the first year of follow-up; in the others recurrence occurred later, up to 11.5 years. Rebleeding had a high mortality rate: 70% of patients died as a consequence of their second or third hemorrhage. Univariate and multivariate analyses showed that lobar location of the first hemorrhage was the only significant predictor of rebleeding. Patients with rebleeding were more frequently older, more often had a history of previous transient ischemic attack or ischemic stroke, and less often had hyperlipidemia than patients without rebleeding, although these correlations did not reach statistical significance. During follow-up, poor control of arterial hypertension was found in 7% of hypertensive patients without rebleeding and in 47% of hypertensive patients with rebleeding. CONCLUSIONS Our study showed that rebleeding after a first primary intracerebral hemorrhage is not as uncommon as is usually believed. The risk of rebleeding seems to be particularly high after hemorrhage at the junction of the gray and white matter, a site regarded as typical of hemorrhages due to amyloid angiopathy, and when arterial hypertension is poorly controlled.

Diagnostic specificity of sensory and motor nerve conduction variables in early detection of carpal tunnel syndrome.

SummaryIn the carpal tunnel syndrome (CTS) sensory nerve conduction is more sensitive than motor conduction. However, 8%–25% of the sensory distal latencies in symptomatic hands may still be normal. A systematic study was made of the median, ulnar and radial orthodromic nerve conduction velocities (SNCV) stimulating each of the fingers separately. Four SNCVs from the median nerve, two SNCVs from the ulnar nerve and one from the radial nerve were obtained, and the ratio of the median to radial SNCV and the ratios of the median and ulnar SNCVs were estimated. The significance of these parameters in the diagnosis of the CTS was studied, and a rapid technique for the screening of nerve entrapment in the initial stages of the disease is proposed. Three hundred and seventy-five symptomatic hands were examined. Seventy-five hands showed normal distal latency, in which cases, however, the SNCV of the ring finger was always outside the normal range, while the SNCVs of the thumb, index and middle fingers were abnormal in 64%, 80% and 92% of cases respectively. The amplitudes of the sensory responses were the least sensitive of the parameters studied. Our results suggest that a study of the median nerve digital branch to the ring finger may be of value in providing an easily performed and rapid technique for screening an early median nerve entrapment at the wrist.

Polysomnographic characterization of pergolide-induced sleep attacks in idiopathic PD

Abstract—Both dopamine agonists and levodopa may induce episodes termed “sleep attacks” in patients with PD. These episodes are well detailed behaviorally, but little is known about their neurophysiologic characterization. The authors performed a 24-hour polysomnography (PSG) in a PD patient taking pergolide in combination with levodopa, in which four of these diurnal sleep episodes occurred. PSG findings were followed up after pergolide withdrawal. Sleep episodes shared with narcolepsy both behavioral and EEG findings. However, pergolide partly restored a more physiologic sleep architecture, which was disrupted during therapy with levodopa alone.

Quantitative EEG Mapping, Regional Cerebral Blood Flow, and Neuropsychological Function in Alzheimer’s Disease

The relations between quantitative EEG, regional cerebral blood flow (rCBF), severity of disease and neuropsychological data were analyzed in 31 patients in different stages of Alzheimers disease (AD). As a group the demented patients had higher delta and theta activities, lower alpha activity and lower alpha peak frequency than control subjects. rCBF was reduced in all regions studied but mainly in the temporoparietal areas. An analysis of correlations showed a close relationship between rCBF and certain quantitative EEG parameters in AD patients, mainly the power of the theta and delta bands. Both rCBF evaluation and quantitative EEG provide functional information related to the severity of cognitive impairment.

Animal Model of TIA: An Experimental Study With Intracarotid ADP Infusion in Rabbits

Adenosine diphosphate (8 mg per minute for five minutes) was infused into the carotid artery of 63 rabbits. The effects were twofold: systemic hypotension and platelet aggregation in the cerebral circulation. As a consequence of the last effect, platelet emboli were produced which occluded cerebral arteries in a number and size sufficient to cause cerebral ischemia. Areas of focal ischemia were observed through a cranial window, and documented with antipyrine autoradiography. Platelet thrombi were almost entirely transient, being fragmented and removed within a very short time of cessation of ADP infusion. Consequently, no permanent tissue damage ensued. This experimental model approaches the spontaneous transient ischemic attacks (TIAs) in man, demonstrating that these can be caused by pure platelet emboli. A high cholesterol diet administered for two months prior to ADP infusion did not enhance the effect of the procedure or make the platelet aggregation and the following ischemia longer in duration or more severe.

Regional cerebral blood flow changes following chronic administration of antidepressant drugs

1. Twenty-six patients with major unipolar depression were rated clinically and regional cerebral blood flow (rCBF) determined prior to and after six months of treatment with 75-100 mg/day amitriptyline (n. 16) or 200 mg/day amineptine (n. 10). 2. rCBF was measured in 16 regions over each hemisphere by the Xenon 133 inhalation method and was computed as the initial slope index (ISI). The severity of depression was quantified by the Hamilton rating scale for depression. 3. Baseline rCBF values of depressed patients tended to be lower than those of normal subjects. Significant reductions were observed for all probes exploring the frontal region of the left hemisphere and for some probes exploring the frontal region of the right hemisphere. Chronic treatment with amitriptyline induced a significant increase in rCBF in the left frontal region. Similar results were obtained after treatment with amineptine. 4. Besides confirming frontal lobe dysfunction in depressed patients which is reversed by treatment with classic tricyclic antidepressants, the present results show that this dysfunction may also be reversed by treatment with dopaminergic drugs.

Reduction of cortical myoclonus-related epileptic activity following slow-frequency rTMs. A case study

In a drug-resistant epilepsy patient with continuous forearm/hand positive myoclonia due to a focal cortical dysplasia of the right motor cortex, cortical jerk-related and electromyographic activity were recorded for 15 min before and after 1 Hz rTMS (15 min, 10% below the resting excitability threshold) of the right motor cortex. A stable negative cortical spike, time-locked with contralateral muscle jerks (60 > 100 μV), was detected only at perirolandic electrodes (maximal amplitudes: block 1 = 21.3 μV, block 2 = 22 μV, block 3 = 25.9 μV). After rTMS, only 20 muscle jerks accomplished the criterion of >100 μV; blind back-averaging of these disclosed a topographically similar cortical spike, but with amplitude reduced by at least 50% (11.2 μV). This represents in vivo evidence of the possibility to selectively modulate the activity of an epileptic focus by intervening with local low-frequency rTMS.

Diagnosis of thoracic outlet syndrome Relative value of electrophysiological studies

The diagnostic utility of various electrophysiological techniques was evaluated in patients with thoracic outlet compression syndrome (TOCS). Our results suggest that in true neurogenic TOCS, there is no standard electrophysiological picture, but that this evolves with the severity of the syndrome. The first changes observed are electromyographic, followed by changes in F‐wave and SEPs, followed finally by changes in nerve conduction parameters. EMG study was certainly more informative, showing neurogenic damage not only in limbs with neurological signs but also in about 1/4 of limbs with only subjective symptoms. The study of F‐wave and SEPs does not seem to be particularly helpful, however, in view of the peculiar changes found in these patients, SEPs may be a useful complement to EMG. Nerve conduction studies were of little utility since changes in these parameters are only found in patients with long‐standing anomalies and severe atrophy.

Sensory neural conduction of median nerve from digits and palm stimulation in carpal tunnel syndrome

The median sensory nerve conduction between ring finger and wrist is a suitable parameter for early detection of carpal tunnel syndrome (CTS), although shorter segments of median nerve have also been proposed for the same goal. In order to assess the relative diagnostic value of the sensory nerve conduction velocity (SNCV) of the third palmar branch versus the SNCV of the second palmar branch, generally performed until now, we studied 62 patients with typical signs and symptoms of CTS. The following parameters were evaluated by surface recording: orthodromic SNCVs in digit-wrist segments for median (index = M2, third = M3 and ring = M4 fingers), ulnar (fourth = U4 finger) and radial (thumb = R1) nerves; SNCVs in palm-wrist segments by surface bipolar stimulation at each metacarpo-phalangeal interspace (second = P2 and third = P3 for the median nerve and fourth = P4 for the ulnar nerve); and distal motor latencies of the median and ulnar nerves. No responses at the wrist were recorded in 22.6% of patients after digital stimulation of M4, whereas the SNCV of P3, the palmar nerve branch arising from digital nerves of the medial side of M3 and the lateral side of M4, was measurable in 93.5% of patients. As significantly expressed (P < 0.001) by the increased ratio of the mean values of P2 and P3 in CTS patients, the SNCV of P3 decreased more frequently and to a greater extent than the SNCV of P2.