Showing papers in "JAMA Neurology in 1984"
TL;DR: Recent studies of neuropsychologic deficits following focal subcortical lesions also support a role for these structures in arousal, attention, mood, motivation, language, memory, abstraction, and visuospatial skills.
Abstract: • Subcortical dementia is a clinical syndrome characterized by slowness of mental processing, forgetfulness, impaired cognition, apathy, and depression. First recognized in progressive supranuclear palsy and Huntington's disease, the concept has been extended to account for the intellectual impairment of Parkinson's disease, Wilson's disease, spinocerebellar degenerations, idiopathic basal ganglia calcification, the lacunar state, and the dementia syndrome of depression. Disorders manifesting subcortical dementia have pathologic changes that involve primarily the thalamus, basal ganglia, and related brain-stem nuclei with relative sparing of the cerebral cortex. Recent studies of neuropsychologic deficits following focal subcortical lesions also support a role for these structures in arousal, attention, mood, motivation, language, memory, abstraction, and visuospatial skills. The clinical characteristics of subcortical dementia differ from those of dementia of Alzheimer's type where prominent cerebral cortical involvement produces aphasia, amnesia, agnosia, and apraxia.
547 citations
TL;DR: The location of hypoperfused structures in cognitive disorders of childhood is consistent with a role for an early hypoxic-ischemic event in their origin.
Abstract: • The neural mechanisms involved in learning disorders are largely unknown. We studied three-dimensional regional cerebral blood flow (rCBF) in 13 children with dysphasia and/or attention deficit disorder (ADD), using xenon 133 inhalation and emission computed tomography. The rCBF distribution was abnormal in both hemispheres in all patients, as compared with the mean CBF distribution of nine normal children. Regions of hypoperfusion and, by inference, low metabolic activity were predominantly seen in the periventricular white matter and in border zones between major arterial territories. In patients with dysphasia, parts of both perisylvian regions were hypoperfused, and object-naming tasks failed to produce an increased flow in relevant cortical regions. Patients with different dysphasic syndromes appeared to have different patterns of rCBF. All 11 patients with ADD had hypoperfusion in the white matter of the frontal lobes and seven also in the caudate nuclei region. Methylphenidate hydrochloride increased perfusion in the central region, including the mesencephalon and the basal ganglia, and decreased perfusion of motor and primary sensory cortical areas. The location of hypoperfused structures in cognitive disorders of childhood is consistent with a role for an early hypoxic-ischemic event in their origin.
507 citations
TL;DR: In these studies, damage to the nigrostriatal bundle of the rat was accompanied by apparent increases in the synthesis and release of dopamine from those dopaminergic terminals that remained, and both the activity of the rate-limiting biosynthetic enzyme and the content of the principal DA metabolite were increased in striatum relative to DA levels.
Abstract: • Parkinson's disease usually involves a lengthy preclinical period during which few neurological symptoms are observed despite extensive damage to the dopaminergic nigrostriatal bundle. Injury to this projection in the rat also fails to produce major neurological dysfunctions. In our studies, damage to the nigrostriatal bundle of the rat, resulting in the loss of up to 95% of the dopaminergic terminals in striatum, was accompanied by apparent increases in the synthesis and release of dopamine (DA) from those dopaminergic terminals that remained. More specifically, both the activity of the rate-limiting biosynthetic enzyme, tyrosine hydroxylase, and the content of the principal DA metabolite, dihydroxyphenylacetic acid, were increased in striatum relative to DA levels. The increases were exponentially related to DA loss.
342 citations
TL;DR: A brief (ten-minute), easily administered battery of four psychological tests was developed to classify successfully 98% of patients with mild dementia of the Alzheimer's type and healthy older persons matched for age, sex, and social position.
Abstract: • A brief (ten-minute), easily administered battery of four psychological tests was developed to classify successfully 98% of patients with mild dementia of the Alzheimer's type and healthy older persons matched for age, sex, and social position. Only two of 84 persons (one demented, one healthy) were misclassified. The four tests are the logical memory and mental control subtests of the Wechsler Memory Scale, Form A of the Trailmaking Test, and word fluency for letters S and P.
323 citations
TL;DR: Patients with chronic progressive multiple sclerosis were compared with age- and education-matched control groups on a battery of clinical and experimental memory measures and showed mild memory disturbance, associated with a greater use of psychotropic medications and a higher incidence of reactive depression.
Abstract: • Forty-four patients with chronic progressive multiple sclerosis (MS) were compared with age- and education-matched control groups on a battery of clinical and experimental memory measures. Patients with MS performed substantially below the control groups on both immediate learning and delayed recall tasks, particularly in the retrieval of spatial information. The MS sample was subdivided into three groups using a cluster analytic procedure. One group (N = 9) performed well below expectations on memory tasks, exhibited signs of global cognitive disturbance, and had an atypical personality adjustment, characterized by irritability, social withdrawal, and apathy. A second group (N = 19) showed mild memory disturbance, associated with a greater use of psychotropic medications and a higher incidence of reactive depression. A third group (N = 16) performed normally on memory measures. The three groups of patients with MS did not differ in length or overall severity of illness.
317 citations
TL;DR: The performance of patients with PD was considerably impaired on several tasks from both groups, and this impairment was not related to depression or intellectual impairment.
Abstract: We investigated the role of perceptual and motor factors in visuospatial impairment in 30 patients with Parkinson's disease (PD) and 30 matched controls. All subjects were administered visuospatial tests, which included "visuoperceptual" tasks, requiring minimal motor responses, and "visuomotor" tasks. The performance of patients with PD was considerably impaired on several tasks from both groups, and this impairment was not related to depression or intellectual impairment. Patients in stage 3 of the disease tended to show the greatest impairment. Those in stage 1 (unilateral symptoms), however, tended to show more impairment than those in stage 2.
298 citations
TL;DR: Drowsiness was the major symptom, which began on the first to fourth day after the ictus and which was accompanied by asymmetry in pupillary size, and Babinski's sign contralateral to the hemiparesis in five patients.
Abstract: • We studied prospectively the syndrome of brain edema after a large infarction in 12 patients. The major symptom was drowsiness, which began on the first to fourth day after the ictus and which was accompanied by asymmetry in pupillary size of 0.5 to 2.0 mm in eight patients, periodic breathing in seven, and Babinski's sign contralateral to the hemiparesis in five. These accompanying signs appeared several hours after drowsiness in some patients. Seven patients had brain death, one died of sepsis after recovering from brain swelling, and only four survived. In six patients in whom intracranial pressure was continuously measured, levels persistently above 15 mm Hg were associated with eventual brain death (four patients) and levels below 15 mm Hg were associated with survival (two patients).
280 citations
TL;DR: The results suggest that the memory disorder of patients with HD may appear much more severe when recall rather than recognition test paradigms are employed, due to an inability to generate strategies necessary to search their short- and long-term memories.
Abstract: • Patients with Huntington's disease (HD), patients with alcoholic Korsakoff's syndrome, and normal control subjects were compared on tests of skill learning (mirror reading) and verbal recognition. Like previously reported results, the patients with Korsakoff's syndrome acquired the mirror-reading skill at a normal rate but were severely impaired in their recognition of the words used on the mirror-reading task. In contrast to the amnesic patients, the demented patients with HD were retarded in their ability to acquire this skill but showed normal verbal recognition. Besides emphasizing substantial differences in the anterograde memory disorders of these two patient populations, the results suggest that the memory disorder of patients with HD may appear much more severe when recall rather than recognition test paradigms are employed. This failure of recall by the patients with HD may be due to an inability to generate strategies necessary to search their short- and long-term memories.
270 citations
TL;DR: A map that bore a close relationship to previous maps and took into consideration modern data on physiology and connections was produced, with special attention paid to the inferior parietal lobule.
Abstract: • Architectonic parcellation of the parietal lobes of eight human brains, with special attention paid to the inferior parietal lobule, resulted in a map that bore a close relationship to previous maps and took into consideration modern data on physiology and connections. Two general parietal zones were distinguished, one above and the other below the intraparietal sulcus, similar to the dorsal-ventral distinction suggested for the frontal lobe. Five areas were recognized in the inferior parietal lobule, of which areas parietal areas EG (PEG), G (PG), and occipitoparietal G (OPG) were in the angular gyrus. A lateralization toward the right was found for area PEG, an area structurally similar to the visually related cortices of the posterior superior parietal region. A lateralization toward the left was found for area PG, but only in brains with a larger left planum temporale. The asymmetry in area PG seemed to be linked to other asymmetries present in language areas, whereas the right-sided area PEG preponderance showed no relation to the language asymmetries.
267 citations
TL;DR: A double dissociation was found: the performance of patients with AD was found to be significantly impaired on tasks involving extrapersonal perception and construction but not on the test of egocentric space, while salient deficits were apparent when manipulation of personal space was required.
Abstract: • Because the severity of memory disorders exhibited by neuropsychiatric patients overshadows other cognitive deficiencies, we explored the visuoperceptual and constructive abilities of patients with Alzheimer's (AD) or Huntington's (HD) disease. The tasks assessed directional sense with reference to egocentric space, as well as visuodiscriminative and constructive skills of patients and matched controls. A double dissociation was found: the performance of patients with AD was found to be significantly impaired on tasks involving extrapersonal perception and construction but not on the test of egocentric space. In contrast, visuoconstructive performance by patients with HD was not significantly impaired, while salient deficits were apparent when manipulation of personal space was required. These differential patterns of defects may have been aligned with neuropathologic changes in different cortical and subcortical structures, respectively, in patients with AD and HD.
183 citations
TL;DR: When behavioral patterns were assessed, patients with MS demonstrated a significantly higher rate of depressed affective disorders than patients with the other two diseases, suggesting multiple sclerosis may present a neurologic model for mood disturbance.
Abstract: • Certain CNS diseases can produce specific behavioral abnormalities. We used a computer search technique to identify all inpatients at Strong Memorial Hospital, Rochester, NY, who had received diagnoses of multiple sclerosis (MS), temporal lobe epilepsy (TLE), and amyotrophic lateral sclerosis (ALS) between 1965 and 1978. We found 368 patients with MS, 402 patients with TLE, and 124 patients with ALS. These groups were matched against the Monroe County (New York) Psychiatric Register to determine patterns of behavioral pathology. Prevalence rates for psychiatric contact were not significantly different between MS and TLE (19.3% v 22.9%), but both were higher than the prevalence rate for ALS (4.8%). When behavioral patterns were assessed, patients with MS demonstrated a significantly higher rate of depressed affective disorders (61.97% of register matches) than patients with the other two diseases. Multiple sclerosis may present a neurologic model for mood disturbance.
TL;DR: Two cases of subarachnoid hemorrhage that occurred within several minutes of "snorting" cocaine were studied, finding that the bleeding was from an anterior communicating artery aneurysm and an arteriovenous malformation in the temporoparietal region.
Abstract: • We studied two cases of subarachnoid hemorrhage that occurred within several minutes of "snorting" cocaine. In one case the bleeding was from an anterior communicating artery aneurysm, and in the other case from an arteriovenous malformation in the temporoparietal region. To our knowledge, this hazard of cocaine abuse has not been previously reported.
TL;DR: There has long been a controversy over the cause of trigeminal neuralgia, and most clinical data favor a peripheral cause, but most of the experimental data tend to favor a central mechanism.
Abstract: • There has long been a controversy over the cause of trigeminal neuralgia. Most clinical data favor a peripheral cause. However, most of the experimental data tend to favor a central mechanism. Drugs that are effective in the treatment of trigeminal neuralgia facilitate segmental inhibition in the trigeminal nucleus, as well as depressing excitatory transmission. The most plausible hypothesis to reconcile all of these observations is that trigeminal neuralgia has a peripheral cause and a central pathogenesis. Chronic irritation of the trigeminal nerve apparently leads to both a failure of segmental inhibition in the trigeminal nucleus, and ectopic action potentials in the trigeminal nerve. This combination of increased firing and impaired efficiency of inhibitory mechanisms leads to paroxysmal discharges in the trigeminal nucleus, which are perceived as attacks of trigeminal neuralgia when they involve nociceptive trigeminothalamic-relay neurons.
TL;DR: It is found that the incidence of clinically significant pain in patients with multiple sclerosis, excluding headache and paresthesia, was 28.8%.
Abstract: • We reviewed 317 patients with multiple sclerosis (MS) and found that the incidence of clinically significant pain, excluding headache and paresthesia, was 28.8%. Successful treatment requires recognition of the pathophysiology of the pain syndromes encountered in MS. Antidepressant drugs have been of particular value in the treatment of chronic pain in these patients.
TL;DR: The above findings suggest that patients with migraine show sympathetic hypofunction together with denervation hypersensitivity of the iris and the arteries, and that a defective noradrenergic nervous system may play a role in the pathogenesis of migraine.
Abstract: • The autonomic nervous function in patients with migraine was studied during headache-free intervals. The following observations were made: (1) a decrease in overshoot in Valsalva's maneuver; (2) orthostatic hypotension; (3) low levels of plasma norepinephrine in the steady state; (4) failure in elevation of the plasma norepinephrine level after head-up tilting; (5) dilatation of the pupils after instillation in the eye of 1.25% epinephrine; and (6) a long recovery time in tests by bolus injection of 0.1 μg of norepinephrine bitartrate per kilogram. The above findings suggest that patients with migraine show sympathetic hypofunction together with denervation hypersensitivity of the iris and the arteries, and that a defective noradrenergic nervous system may play a role in the pathogenesis of migraine.
TL;DR: The relationship of the tibial nerve to the tarsal tunnel was investigated and the calcaneal nerve showed great variability; in seven cadavers, it arose within, in eightcadavers proximal to, and in five cadaver there were multiple branches arising both proximalto and within the tARSal tunnel.
Abstract: To provide an anatomical basis for diagnosis and treatment of the tarsal tunnel syndrome, the relationship of the tibial nerve to the tarsal tunnel was investigated in 31 feet of 20 cadavers. The bifurcation into medial and lateral plantar nerves occurred within 1 cm of the malleolar-calcaneal axis in 90% of the feet. Seven of 11 bilateral specimens were bilaterally symmetrical in the bifurcation location; three varied within 1 cm between sides; and in the fourth cadaver, one side bifurcated at 3 cm and the other at 5 cm proximal to the axis. The calcaneal nerve showed great variability; in seven cadavers, it arose within, in eight cadavers proximal to, and in five cadavers there were multiple branches arising both proximal to and within the tarsal tunnel.
TL;DR: Patients with closed head injuries who had Glasgow coma scale scores of 7 or less were studied with evoked potentials soon after trauma, and the BAEPs and VEPs were reliable predictors of an unfavorable but not a favorable outcome and the SSEPs reliably predicted both kinds of outcomes.
Abstract: Patients with closed head injuries who had Glasgow coma scale scores of 7 or less were studied with evoked potentials soon after trauma. Of the patients, 39 had brain-stem auditory evoked potentials (BAEPs); 12, stroboscopic visual evoked potentials (VEPs); and 23, short-latency somatosensory evoked potentials (SSEPs). Evoked potential results were graded from 1 (normal) to 4 (most abnormal). Outcomes were categorized by the Glasgow outcome scale, with good outcome and moderate disability further classified as "favorable" and severe disability, vegetative state, and death as "unfavorable." The BAEPs and VEPs were reliable predictors of an unfavorable but not a favorable outcome. The SSEPs reliably predicted both kinds of outcomes. No instances of "false pessimism" were encountered in any modality. Evoked potential results were more reliable than intracranial pressure, pupillary light reaction, or motor findings in predicting outcome. Frequent occurrence of peripheral auditory injuries was shown.
TL;DR: Because part of pathologic laughing and crying seems to be caused by the decreased function of the dopaminergic neuron, levodopa or amantadine is worth trying.
Abstract: • Levodopa or amantadine hydrochloride was administered to 25 patients with pathologic laughing and/or crying. This symptom was markedly improved in ten cases, most of which were devoid of a cortical atrophy or a periventricular lucency in computed tomographic scan and also devoid of a severe dementia or a disturbance in activity of daily living. The concentration of homovanillic acid in the CSF of the patients was significantly decreased, whereas the concentration of 5-hydroxyindoleacetic acid remained within the normal limit. Because part of pathologic laughing and crying seems to be caused by the decreased function of the dopaminergic neuron, levodopa or amantadine is worth trying.
TL;DR: On retrospective review of records of 150 patients with atrial fibrillation, 31% experienced a stroke or peripheral embolism, and thromboembolism typically occurred in patients whose AF was undetected prior to the infarction.
Abstract: On retrospective review of records of 150 patients with atrial fibrillation (AF), 31% experienced a stroke or peripheral embolism. The AF was not associated with cardiac valvular disease in 80% of the 150 patients. Most of the cerebral infarcts were large, disabling, and unheralded by transient ischemic attack. The thromboembolism typically occurred in patients whose AF was undetected prior to the infarction. Half of the patients with an ischemic event suffered multiple events, with one fourth of the recurrences arising within two weeks.
TL;DR: Most WAIS subtests appeared to evaluate primarily either verbal or visuospatial cognitive functions and either left parasylvian or right posteroparietal cortical activity, which was most closely associated with verbal and performance IQ scores.
Abstract: • We compared local cerebral glucose metabolism, as determined by positron emission tomography following administration of fluorodeoxyglucose F 18, with Wechsler Adult Intelligence Scale (WAIS) scores in 22 right-handed persons. Five study subjects were normal volunteers and the remainder had Alzheimer's disease. Subtest scores within the verbal IQ group or the performance IQ group were generally highly interrelated; there was usually no correlation between the verbal and performance subtests. The cortical distribution of regions in which glucose metabolism was most closely associated with verbal subtest scores generally centered in the left parasylvian area. In contrast, scores on the performance subtests mainly localized to the right posterior parietal region. Most WAIS subtests thus appeared to evaluate primarily either verbal or visuospatial cognitive functions and either left parasylvian or right posteroparietal cortical activity.
TL;DR: Patients who consult physicians for language disturbance should be evaluated and followed up both for evidence of progressive language deterioration and for the development of a generalized dementia.
Abstract: • Six patients manifested progressive language disturbance, resembling aphasia secondary to a focal dominant hemisphere lesion, as either an isolated initial symptom or a prominent early feature of a more generalized dementing illness. None had a history of transient ischemic attacks or stroke, and in all cases an extensive clinical and laboratory investigation failed to show either a focal brain lesion or a definable etiology of dementia. This article discusses the relationship of isolated or early aphasia to known dementing syndromes. Patients who consult physicians for language disturbance should be evaluated and followed up both for evidence of progressive language deterioration and for the development of a generalized dementia.
TL;DR: It is suggested that alterations in muscle related to neurogenic changes may cause the typical pain of Guillain-Barré syndrome.
Abstract: • The clinical features of pain were prospectively analyzed in 29 consecutive patients with Guillain-Barre syndrome (GBS). Sixteen (55%) had characteristic pain early in the illness described as similar to the muscular discomfort following exercise ("charley horse"). Pain preceded weakness by one to five days in four patients. The anterior and posterior aspects of the thighs, the buttocks, and the low part of the back were most frequently affected. Pain was frequently worse at night. Specific clinical signs or electrophysiologic abnormalities were not associated with pain, but serum creatine kinase level was elevated in ten of 13 patients with pain and only one of eight without pain. A review of previously reported pathologic material in five patients with GBS failed to disclose a relation between inflammation of dorsal root ganglia and pain. These results suggest that alterations in muscle related to neurogenic changes may cause the typical pain of GBS.
TL;DR: At least 7,000 persons in the United States each year have neurologic disorders attributable to CMV infection, and previously healthy adults, meningoencephalitis and retinitis occur more commonly in immunosuppressed patients, particularly among organ transplant recipients.
Abstract: • Infection with human cytomegalovirus (CMV) occurs in nearly 1% of live-born infants, and from 60% to 80% of the inhabitants of the United States acquire CMV infection by mid adulthood. While neurologic disorders do not develop in the majority of congenitally infected infants, congenital CMV infection can severely damage the developing nervous system, causing microcephaly, psychomotor retardation, seizures, and deafness. Furthermore, approximately 10% of infants who are asymptomatic at birth subsequently exhibit sensorineural hearing loss. In the adult, CMV infection has been associated with the Guillain-Barre syndrome, meningoencephalitis, and retinitis. Although Guillain-Barre syndrome can accompany CMV infections In previously healthy adults, meningoencephalitis and retinitis occur more commonly in immunosuppressed patients, particularly among organ transplant recipients. In total, at least 7,000 persons in the United States each year have neurologic disorders attributable to CMV infection.
TL;DR: Among 6,638 cases reported to the Cooperative Study of Intracranial Aneurysms and Subarachnoid Hemorrhage were 477 cases in which the cause of hemorrhage could not be determined after carotid and vertebral angiography.
Abstract: • Among 6,638 cases reported to the Cooperative Study of Intracranial Aneurysms and Subarachnoid Hemorrhage were 477 cases in which the cause of hemorrhage could not be determined after carotid and vertebral angiography. These patients were followed up for up to 24 years after hemorrhage. Twenty patients were subsequently found to have an aneurysm or arteriovenous malformation missed by the first angiographic survey. After six-month survival, the rate of recurrent hemorrhage was a maximum 0.86% per year. Survival was significantly better than that of patients with verified ruptured aneurysms managed conservatively in this cooperative study. For normotensive patients who survived the first six months, the life expectancy for the next 20 years equaled that of an age- and sex-matched US population. Hypertensive patients had a higher mortality than normotensive patients.
TL;DR: It is hypothesize that both the SOREM and O2 desaturation findings in patients with the Prader-Willi syndrome are also a result of hypothalamic changes.
Abstract: • Nine patients with the Prader-Willi syndrome, ranging in age from 3 to 21 years, were examined clinically as well as studied in the sleep laboratory. They had striking disturbances of sleep-wakefulness patterns. All patients except one had the symptom of excessive daytime sleepiness. The most striking finding was the presence in five patients of rapid-eye-movement (REM) sleep occurring at sleep onset (SOREM). None of the patients had the condition of sleep apnea. One patient, however, demonstrated severe hypoventilation during REM sleep; the lowest value recorded for O2saturation was 40%, with a consistent value below 50% for as long as ten to 15 minutes. Previous findings have indicated that the Prader-Willi syndrome is of hypothalamic origin. We hypothesize that both the SOREM and O2desaturation findings in our patients with the Prader-Willi syndrome are also a result of hypothalamic changes.
TL;DR: Gait ataxia was associated with a state of agitation and confusion when the patient was admitted for meningitis, and high sequelae ratings on reexamination were associated with an affected consciousness at the acute stage of the disease.
Abstract: • We interviewed and neurologically reexamined 94 patients who had previous pneumococcal meningitis. The findings were allocated into groups with and without a causal relationship to the meninigitis. The main sequelae after meningitis were dizziness (23%), tiredness (22%), mild memory deficits (21%), and gait ataxia (18%), whereas other focal neurologic signs were rare. By a rating (0 to 5) of the presence and severity of sequelae after meningitis, 54% of the patients were found to have sequelae. The clinical condition at the time of acute illness was studied in subgroups of patients who had different neurologic sequelae or high sequelae ratings. Gait ataxia was associated with a state of agitation and confusion when the patient was admitted for meningitis. High sequelae ratings on reexamination were associated with an affected consciousness at the acute stage of the disease and with high numbers of WBCs in the CSF at the time of hospitalization.
TL;DR: It is speculated that the vasomotor phenomena in migraine may play a major role in the cause of transient global amnesia, and regional cerebral blood flow abnormalities differed from those seen in patients with carotid transient ischemic attacks (TIAs) and vertebrobasilar TIAs.
Abstract: • Twelve patients with transient global amnesia (TGA) were studied. Seven (58%) of the 12 had a headache during their attack; five (42%) of the 12 were migraineurs. Measurement of regional cerebral blood flow (rCBF) by the xenon Xe 133 inhalation method showed similar patterns of flow in five of the seven patients tested. The rCBF abnormalities were impaired vasomotor response in the watershed area between the middle cerebral artery and posterior cerebral artery territories, and/or focal ischemia in the inferior part of the temporal lobe. These rCBF abnormalities differed from those seen in patients with carotid transient ischemic attacks (TIAs) and vertebrobasilar TIAs. We speculate that the vasomotor phenomena in migraine may play a major role in the cause of TGA.
TL;DR: Twelve cases of large- and medium-sized cerebral artery stenosis and/or occlusion associated with bacterial meningitis occurred.
Abstract: • Twelve cases of large- and mediumsized cerebral artery stenosis and/or occlusion associated with bacterial meningitis occurred. Neurological complication due to arterial involvement developed in seven patients on the third and fourth days of illness; in one patient, it developed on the fifth day, and in another it developed on the 14th day. In three cases, this could not be determined. Arterial stenosis is considered primarily to result from arterial spasm due to humoral factors that may be elaborated within the CSF or arterial wall, as in the cases of ruptured aneurysm; and secondarily, from to inflammatory involvement of major vessels at the base of the brain and from irritation by angiographic contrast material.
TL;DR: It is concluded that SERs are useful in signaling cerebral ischemia and the need for a shunt during CEA, although measurement of stump pressure would have indicated the necessity of aShunt in eight additional operations.
Abstract: • During carotid endarterectomy (CEA), we monitored somatosensory evoked responses (SERs) ipsilaterally over the scalp following stimulation of the contralateral median nerve at the wrist. Thirty-eight CEAs in 36 patients were studied. Of the 10 CEAs performed with patients under general anesthesia, three involved marked changes in SERs, reversed by shunt insertion. The remaining 28 CEAs were done with patients under local anesthesia. The SERs remained stable during an average clamp time of 30 minutes in all except one patient, in whom SER changes developed within a minute of clamping; the changes were reversed by shunt placement. Four of the 38 CEAs required a shunt based on SER changes, although measurement of stump pressure (
TL;DR: The ability of mature oligodendrocytes to divide and to remyelinate axons in the adult may play an important role in the recovery from MS attacks.
Abstract: Primary demyelination can be caused by injury to oligodendrocytes or to the myelin sheaths that these cells maintain. Although remyelination does take place in multiple sclerosis (MS), its possible role in the recovery from MS attacks has been inadequately considered, partly because of the belief that oligodendrocytes, once destroyed, cannot be replaced in the adult. The injection of lysolecithin into the mouse spinal cord causes primary demyelination, followed by the generation of new oligodendrocytes and remyelination. By using a pulse label of tritiated thymidine, this electron-microscopic autoradiographic study demonstrated a source of these regenerated oligodendrocytes. The replacement of oligodendrocytes can occur through the division of preexisting oligodendrocytes. This is the first demonstration that mature oligodendrocytes are capable of dividing in older animals. These results lend support to recent observations of an apparent proliferation of these cells in an active MS lesion. We believe that the ability of mature oligodendrocytes to divide and to remyelinate axons in the adult may play an important role in the recovery from MS attacks.