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At least 145 records · Page 8Linked to original sources
PubMed1992

Cisplatin neuropathy: clinical course and neurophysiological findings.

Sixteen patients treated with cisplatin (CDDP) 40 mg/m2 on days 1-5 every 4 weeks for three courses (cumulative dose 600 mg/m2) were clinically and neurophysiologically tested before, during and 1, 3, 6, 9 and 12 months after CDDP administration. The first symptoms of polyneuropathy occurred in 4 of 9 patients after the second course (cumulative dose 400 mg/m2). One month after treatment 1 of 9 patients was asymptomatic, 5 complained of symptoms and 3 showed clinical and neurophysiological signs of polyneuropathy. Three months after CDDP all patients were affected. Clinical and neurophysiological signs of severity progression were noted up to 6 months after treatment with CDDP.

Action Potentials↗
PubMed1995

Neurophysiological assessment of peripheral nerve and spinal cord function in asymptomatic HIV-1 infection: results from the UCMSM/Medical Research Council neurology cohort.

As part of the Medical Research Council prospective study of the neurological complications of HIV infection, neurophysiological tests of spinal cord and peripheral nerve function were recorded in a cohort of homosexual or bisexual men. The studies included motor and sensory nerve conduction studies, vibration perception thresholds, somatosensory evoked potentials and motor evoked potentials elicited by magnetic stimulation. The results were compared with markers of immune function. The findings from 114 volunteers were analysed in a cross-sectional study. Fifty-nine were HIV-seropositive but asymptomatic, 26 had progressed to the symptomatic stages of HIV disease and 29 were persistently HIV-seronegative. There was some evidence of a mild sensory axonopathy in the symptomatic HIV-seropositive group. No differences were detected between the asymptomatic HIV-seropositive group and the HIV-seronegative comparison group. There were no consistently significant correlations between the neurophysiological measurements and CD4 counts and beta 2-microglobulin levels. On repeated testing, there was no evidence of a trend towards deterioration over a mean period of approximately 3 years in 36 HIV-seropositive subjects who remained asymptomatic compared with 22 HIV-seronegatives. These findings have failed to demonstrate neurophysiological evidence of spinal cord or peripheral nerve dysfunction in the asymptomatic stages of HIV infection.

Adult↗
PubMed1996

Event-related potentials--neurophysiological tools for predicting emergence and early outcome from traumatic coma.

OBJECTIVE: To determine the prognostic value of multimodal evoked potentials (EPs) and event-related (ERPs) potentials in coma (Glasgow Coma Score <8), after severe traumatic brain injury (TBI). DESIGN: Prospective, longitudinal study of neurophysiological responses recorded during traumatic coma. SETTING: Intensive Care Unit, Frenchay Hospital, Bristol, UK. PARTICIPANTS: Fifty-four comatose TBI patients (age range 1-80 years, mean 36.4). METHODS: Neurophysiological responses were recorded from 11 scalp electrodes with earlobe reference. Conduction times were measured for brainstem auditory, flash visual and somatosensory, short-latency EPs. Peak latencies and amplitudes were determined for long-latency components of visual and auditory ERPs, generated by passive "oddball" paradigms. These neurophysiological and various clinical parameters were correlated with patient outcome using Pearson's coefficient. MAIN OUTCOME MEASURE: Three month Glasgow Outcome Scale (GOS). RESULTS AND CONCLUSION: Highly significant (P <0.001) correlations exist between long-latency ERP components and 3-month outcome. Short-latency EPs, brainstem (wave I-V) and somatosensory conduction times also correlate significantly with the GOS (P <0.01). Of the clinical measurements, pupillary response patterns, APACHE II and Glasgow Coma Scores (GCS) correlate significantly with outcome, as do the retrospective measures of duration of coma and post-traumatic amnesia (PTA) in survivors. Unfortunately, due to variance of long-latency responses, even in controls, absolute values cannot be relied upon as prognosticators. The presence of "mismatch negativity" predicted the return of consciousness (89.7% sensitivity and 100% specificity) and preceded changes in GCS. Its latency was the single best indicator of 90-day outcome from coma (r = -0.641).

Acoustic Stimulation↗
PubMed1998

Natural history of carpal tunnel syndrome according to the neurophysiological classification.

Although many studies on carpal tunnel syndrome (CTS) have been reported, few data on the natural history of CTS are available. Knowledge of the natural course of the disease has significant clinical and therapeutic value. We prospectively followed up 80 cases of untreated CTS. The evaluation was based on self-administered questionnaires and on neurophysiological investigation. According to the neurophysiological classification, cases of CTS were divided into six groups on the basis of impairment severity: negative, minimal, mild, moderate, severe, and extreme. Disease worsening was inversely related to severity of nerve entrapment. On the contrary, improvement was proportionally related to nerve function impairment (except for extreme cases that never improved), and about one-third of mild and moderate cases improved. Most minimally cases remained neurophysiologically unchanged. We hypothesize that in a good percentage of CTS cases, nerve impairment is self-limited. Our data suggest the utility of further studies on the natural course of this common disease.

Adult↗
PubMed2001

[Disordered behavioral control in psychiatric illnesses. Neurophysiological aspects of impulsive behavior].

OBJECTIVE: Dysfunction of behavioral control represents a central component of many psychiatric disorders and may be connected with self-mutilating and antisocial behavior. However, only a few studies have investigated objective assessment and quantification of impulsive behavior, which is relevant for psychiatric practice and research. Because new techniques enable objective assessment of behavior generation and execution, the current knowledge about neurophysiological aspects of behavioral control is summarized. METHOD: The contemporary literature on neuronal mechanisms of initiation and execution of behavior and movements and new neurophysiological methods and findings are discussed in respect to their application in psychiatry. RESULTS: Behavior, defined as movements of a body in time and space, is the result of cortical and subcortical processes. These consist of two general components: (1) perception and selection of a stimulus and (2) execution of a movement, including decision and planning phases. Planning and execution, modulated by cognition and emotions, are dependent on the balance of inhibitory and excitatory aspects of behavior control. Combined detection of electrical brain activity and kinematic analysis of peripheral movements enables the analysis of control mechanisms. CONCLUSION: Impulsiveness and inhibition of behavior depend on neuronal control mechanisms which can be analyzed by neurophysiological methods. Objective assessment of impulsive behavior related to psychiatric disturbances including eating disorders, substance abuse, and personality disorders may clarify underlying neurobiological mechanisms and enable rational pharmaco- and psychotherapeutic interventions.

Brain↗
PubMed2006

Neurophysiological features of the migrainous brain.

Migraine is a disorder in which central nervous system (CNS) dysfunction might play a pivotal role. As there are no consistent structural disturbances, clinical neurophysiology methods seem particularly suited to study its pathophysiology. This chapter will focus on a review of neurophysiological studies that have provided an insight into migraine pathogenesis. The results are in part contradictory, which may be due to the methodology, patient selection or timing of study. Nonetheless, quantitative electroencephalography and magnetoencephalography recordings during migraine attacks provide strong, though indirect, evidence favouring the occurrence of spreading cortical depression during attacks of migraine with, and possibly without, aura. Evoked cortical potential and nociceptive blink reflex studies demonstrate that lack of habituation during repetitive stimulation is a reproducible CNS dysfunction interictally in both migraine with and without aura. Transcranial magnetic stimulations show excitability changes of the visual cortex. The interictal migrainous CNS dysfunction is likely to play a role in migraine pathogenesis, has a familial character and undergoes periodic modulations with quasi-normalisation just before, during an attack and after treatment with certain prophylactic agents. In addition, neurophysiological methods have revealed subclinical abnormalities of cerebellar function and neuromuscular transmission, which may improve phenotyping of migraineurs for genetic and therapeutic studies.

Brain↗
PubMed1999

Italian multicentre study of carpal tunnel syndrome: clinical-neurophysiological picture and diagnostic pathway in 461 patients and differences between the populations enrolled in the northern, central and southern centres. Italian CTS Study Group.

The economic trend in our country, as in other countries, now requires us to pay more attention to the social and economic aspects of health. Therefore, it is important to evaluate the diagnostic pathway and the socioeconomic aspects of pathologies. The Italian CTS Study Group performed a wide multicentre and multidimensional study (through a patient-, physician- and neurophysiologically oriented evaluation) on 461 idiopathic CTS patients to evaluate the clinical-neurophysiological picture and the diagnostic pathway. The whole population and the differences between the populations enrolled in the neurophysiological centres of the northern, central and southern parts of Italy were analysed. This study provided new and interesting information. As concerns the whole population, we observed different diagnostic pathways in relation to the level of schooling. As concerns the comparison of the populations, the southern centres have a population of CTS patients with higher frequency of hand stress and more severe nerve impairment.

Adult↗
PubMed2003

Neurophysiological features in relation to clinical signs in clinically diagnosed corticobasal degeneration.

We investigated the association between clinical and neurophysiological characteristics in patients with a clinical diagnosis of probable corticobasal degeneration (CBD), and searched for neurophysiological features supporting the diagnosis in life. Ten patients with clinically probable CBD underwent comprehensive neurological evaluation and brain MRI. Long latency reflexes (LLR), upper limb somatosensory (SEP) and motor evoked (MEP) potentials were recorded. The mini-mental state examination (MMSE), the phonemic verbal fluency test (PVFT) and the De Renzi ideomotor apraxia test were also performed. Polygraphic EEG was performed in the six patients with myoclonus. The SEP N30 frontal component was absent bilaterally in four patients, was absent on the left side in one, and had increased latency in other three. MEPs were abnormal in four patients (three had prolonged central motor conduction time, one of whom also had increased MEP threshold, and one had increased MEP threshold). All six patients with myoclonus had enhanced LLRs at rest, which were also of abnormally increased amplitude during motor activation; latencies were generally shorter than in classic cortical reflex myoclonus. On back-averaging, no EEG spikes time-locked to EMG activity were found in any myoclonus patient. Five patients were demented by MMSE, eight had ideomotor apraxia scores in the ideomotor apraxia range and five had defective verbal fluency. Brain MRI revealed asymmetric cortical atrophy in all patients, particularly evident frontoparietally. Neurophysiological techniques, particularly LLR, can assist CBD diagnosis especially in patients with myoclonus. Patients with evident parkinsonism had greater SEP N30 (frontal) abnormalities, while most patients with marked paresis had slower MEP times.

Aged↗
PubMed1977

Acrylamide autonomic neuropathy in the cat. Part 1. Neurophysiological and histological studies.

Neurophysiological and histological studies have been performed on the sympathetic nervous system of cats poisoned with acrylamide. The neurophysiological studies indicate that the large and small diameter myelinated fibres are damaged in the sympathetic nervous system in association with damage to the fibres of the peripheral nervous system. Quantative histological studies confirmed and extended the neurophysiological findings; there was a loss of myelinated fibres of all diameters from the sympathetic, parasympathetic and peripheral nervous system.

Acrylamides↗
PubMed1996

X-linked bulbar and spinal muscular atrophy, or Kennedy disease: clinical, neurophysiological, neuropathological, neuropsychological and molecular study of a large family.

We report the clinical, neurophysiological, neuropsychological, neuropathological and molecular findings in a large family with X-linked bulbar and spinal muscular atrophy (X-BSMA). Molecular study, performed in 28 family members, showed an increase in the number of CAG repeats in 6 affected males (including 2 presymptomatic patients), and in 10 females, of whom 5 were obligate carriers. All symptomatic patients showed, besides the typical manifestation of X-BSMA, neurophysiological signs of sensory nerve involvement, and abnormal findings in neuropsychological tests. Sural nerve biopsy, performed in two patients, was consistent with axonal atrophy and slow-rate degeneration, with secondary demyelination. Neurophysiological alterations were also present in 6 out of 8 carriers, consisting of neurogenic EMG changes in 3 cases and abnormal sensory action potentials (SAP) and reduced conduction velocity of the sural nerve in 3 cases. Abnormalities of at last two neuropsychological tests were found in 6 out of 8 carriers. Alterations of the sensory nerves in X-BSMA patients have been previously reported in some cases; however, we demonstrate for the first time sensory nerve involvement also in carriers. Evidence of central nervous system involvement, with neuropsychological impairment in all symptomatic patients and in some carriers, is another feature of this family, not previously reported in X-BSMA. In spite of the variable phenotypic features, the number of CAG repeats ranged from 40 to 44 in the affected patients, indicating that phenotypic expression was not related to the size of the mutation, but was probably age-related.

Adolescent↗
PubMed1983

Dynamic neurophysiological correlates of mental processes.

The study of neurophysiological correlates of states and activity has revealed different mechanisms of the brain. Infraslow physiological processes (ISPP) as well as impulse activity of neurons and neuronal populations (NIA) were recorded during the performance of psychological and other trials by the subject. Subjects were neurological patients diagnosed and treated with implanted electrodes. We found correlates of mental activity to be reproducible (stable) in some brain areas and variable in others, which confirmed our concept that mental activity is maintained by cortical-subcortical functional system with links of different degrees of rigidity. One of the ISPP types, omega-potential, was shown to reflect quantitatively the state of the brain areas. We have described NIA rearrangements accompanying mental operations and revealed the complimentary character of various NIA rearrangements. Extremely promising in the investigation of neurophysiological correlates of mental processes, is the study of the relationship of local and distributed rearrangements in various neurophysiological processes, as well as combination of averaging with the study of correlates of single mental acts. Stability, combined with the dynamic character of rearrangements of physiological processes in the brain, seems to be its fundamental property responsible for informational capacity of the brain and adaptational ability of the organism.

Action Potentials↗
PubMed1994

Complaints of neuropathy related to the clinical and neurophysiological assessment of nerve function in patients with diabetes mellitus.

To determine the value of a detailed evaluation of neuropathic sensory complaints in assessing diabetic polyneuropathy, a questionnaire listing different sensory symptoms was compared with a clinical and neurophysiological examination of the peripheral nerves. Thirty-seven insulin dependent and thirty-one non-insulin dependent diabetic patients who were consecutively referred because of suspected polyneuropathy were investigated. In all patients both clinical and neurophysiological examination confirmed the diagnosis of polyneuropathy. Only the scores of the clinical examination were significantly correlated with the scores of the sensory symptoms (r = 0.31, P < 0.01). Using a factor analysis, a dimension of complaints of sensory alteration could be distinguished from a dimension of complaints of neuropathic pain (alpha coefficients 0.88 and 0.86, respectively). Tingling sensations turned out to be an expression of the dimension of complaints of sensory alteration. The scores of clinical and neurophysiological examinations were only significantly correlated with the dimension of sensory alteration (r = 0.38, P < 0.002; r = 0.37, P < 0.02, respectively). We conclude that only symptoms of numbness and tingling sensations in hand and feet are associated with objectively assessed diabetic polyneuropathy.

Diabetes Mellitus, Type 1↗
PubMed1984

Neurophysiological and psychological disorders and occupational exposure to organic solvents.

A number of reports, particularly from Scandinavian countries, claim that painters and workers in other trades in which prolonged occupational exposure to organic solvents may occur develop a type of mental illness characterized principally by impairment of memory and co-ordination and some deterioration of personality. The condition, called 'organic solvent disease', is recognized as a cause of premature retirement and is classed as an occupational disease in certain countries. The conclusions of these reports have been contested and the existence of such a disease entity has been questioned. The publications reporting adverse neurological, neurophysiological and psychological disorders in solvent-exposed workers, and the methods used to determine adverse effects, have therefore been evaluated. In addition, data from animal behavioural studies have been examined but were found to have little or no to have little or no relevance to the reported human disease. The human data indicate that, of the solvents studied, only CS2 provided clear evidence of neurotoxic damage detectable by clinical and pathological examination as well as by neurophysiological measurements (e.g. nerve conduction velocity and nerve action potentials) or neuropsychological techniques (e.g. Rorschach inkblot test and WAIS intelligence tests). In the case of several other solvents and mixtures of solvents commonly used in industry, the evidence of CNS impairment, based principally on the response to questionnaires and the results of neuropsychological and neurophysiological examinations was questionable. A critical evaluation of the reliability of these methods in detecting minor deviations from normal and of their ability to provide acceptable evidence of CNS dysfunction or damage leaves little doubt that these methods are of value in investigating personality, intelligence and memory in the clinical examination of individual patients. However, evidence indicates that they are not suitable for use in epidemiological studies, principally because the variability of response in normal individuals is ill-defined and insufficiently investigated. The same conclusion was arrived at in evaluating the contribution of electroencephalography, computerized axial tomography scanning and other electrophysiological examinations to the diagnosis of brain changes in groups of solvent-exposed and unexposed workers. Furthermore, the personality changes identified (by neuropsychological tests) in painters and other workers exposed to solvents could well be produced by ageing, exposure to lead or mercury, excessive alcohol intake, psychoactive drugs or the ordinary stresses of everyday life.(ABSTRACT TRUNCATED AT 400 WORDS)

Aging↗
PubMed1992

Integration of behavioral and neurophysiological approaches in neurotoxicology.

The validity of behavioral and neurophysiological models can only be assessed with respect to the type of the modelled effect: for acute changes in activation level as well as for chronic motor or sensory deficits both approaches are equally prone to misinterpretation. Validation of behavioral criteria supported by neurophysiological correlates and vice versa is the best protection. In the cognitive and emotional sphere, a shift to testing of the readiness ("fluidity") dimension seems to be promising both in human and animal studies, permitting also more reliable extrapolations and efficient cooperation of behavioral and neurophysiological approaches.

Animals↗
PubMed1988

Comparisons of psychophysical and neurophysiological studies of cochlear implants.

This paper compares psychophysical and neural studies of electrical stimulation of the auditory nerve with the goal of evaluating the relevance of single-unit animal models for the development of cochlear prostheses for profoundly deaf humans. Comparative psychophysical studies with implanted deaf subjects indicate that animal models, at least nonhuman primates, provide a close match to humans, though this is not always true for acoustic stimulation of normal-hearing subjects. However, the human-animal comparisons, especially those involving electrical stimuli, need further study using more carefully matched conditions. Comparisons of psychophysical and neurophysiological thresholds for electrical stimulation in animals reveal consistently higher thresholds in the neural studies. A number of factors which may account for these differences are discussed. A partial resolution of the problem could result from conducting neurophysiological and behavioral studies in the same animal. Finally, comparison of psychophysical and neurophysiological studies of temporal encoding suggest that there may be more information encoded in the auditory nerve than is used by the system, at least for nonspectral frequency discrimination. This points to a need for further analysis of the processing of this information at higher levels in the auditory pathway.

Animals↗
PubMed2004

Clinical features of 1039 patients with neurophysiological diagnosis of carpal tunnel syndrome.

PURPOSE: To describe the clinical features of patients with a neurophysiologic diagnosis of carpal tunnel syndrome (CTS) in the state of Rio Grande do Sul, Brazil. METHODS: We prospectively studied 1039 patients with a neurophysiologic diagnosis of CTS in southern Brazil. All patients completed a clinicoepidemiological questionnaire which included a drawing of the arm and hand, in which they were asked to paint the areas in which paresthesia and pain occurred. In part of the sample, we also investigated the presence of clinical signs such as Tinel's, Phalen, and tenar atrophy. The diagnosis of CTS was performed using a predetermined neurophysiological protocol. RESULTS: A total of 1528 hands were diagnosed with CTS. The severity of CTS was mild in 42% of cases, moderate in 18% and severe in 40%. Patients had a mean age of 48.3 +/- 12.4 years old, and a ratio of 5.6 females to 1 male was observed. Symptoms restricted to the hand and wrist was observed in 51.8% of cases with paresthesia and in 18.5% of cases with pain. In 92.5% of the partially affected hands, paresthesia was present in at least one of the first three fingers, while pain affected the three first fingers in 78.8% of these hands. Pain with a distribution which did not involve the hand occurred in 18.5% of cases, while paresthesia without involvement of the hand occurred in only 1.9%. Distribution of symptoms, according to Katz's hand diagram, showed a classic pattern in 12.6% of affected hands, a pattern classified as probable CTS in 66.3%, and an unlikely CTS pattern in 4.1%. Tinel's and Phalen's sign were observed in 34.2 and 56.3% of the hands, respectively. CONCLUSION: The clinical presentation of CTS is pleomorphic, ranging from the absence of symptoms to very severe cases. This variation probably is dependent on coexistent diseases, such as tendinitis and fibromyalgia, as well as on subjective aspects of the patients.

Adolescent↗
PubMed2004

F-waves: neurophysiology and clinical value.

This review deals with F responses, which are late responses obtained by supramaximal stimulation of virtually all the motor and mixed peripheral nerves. They are recorded over a muscle innervated by the stimulated nerve. The first description of F-waves was published in the fifties. Their neurophysiological mechanisms have been abundantly discussed in the literature leading to a current consensus, whereby F-waves are considered as antidromic responses produced by a pool of motoneurons activated by peripheral nerve stimulation. In the first part of this review, the neurophysiological mechanisms of F-waves as well as the distinction between these and H reflexes are described from a historical point of view. Other late responses are intentionally not reported; nevertheless A-waves are discussed since they are frequently ill-described in a number of conditions. Stimulation and recording procedures as well as F-wave parameters analysis are detailed, with emphasis on measures most useful for clinical purposes. A rigorous F-wave recording method is mandatory for reliable and meaningful analyses. Physiological factors, which influence F-waves such as ageing, drugs and sleep, must be known and their effects discussed. Also, as maturation is an important factor in clinical neurophysiology, data on F-wave ontogenesis are reviewed and discussed. Finally, the different F-wave alterations described so far in the literature, in either peripheral or central disorders, are listed and commented. It is emphasised that F-waves are particularly useful for the diagnosis of polyneuropathies at a very early stage and for the diagnosis of proximal nerve lesions. F-wave recording is indeed one of the rare methods in routine examination allowing at the same time the functional assessment of motor fibres on their proximal segment, and contributing to the evaluation of motoneuronal excitability.

Aging↗
PubMed2005

Neurophysiologic and quantitative sensory testing in the diagnosis of trigeminal neuropathy and neuropathic pain.

This study investigated the utility of neurophysiologic examination and thermal quantitative sensory testing (QST) in the diagnosis of trigeminal neuropathy and neuropathic pain. Fifty-eight patients (14 men), 34 with sensory deficit within the inferior alveolar nerve (IAN) and 24 within the lingual nerve (LN) distribution, were included. Twenty-six patients (45%) reported neuropathic pain. Patients underwent blink reflex (BR) test and thermal QST; sensory neurography was done to the IAN patients. Results of clinical sensory testing were available from the charts of 48 patients revealing abnormal findings in 77% of the IAN and in 94% of the LN patients. The BR test was abnormal in 41%, neurography in 96%, and QST in 91% of the IAN patients. In the LN group, BR was abnormal in 33%, and QST in 100% of the patients tested. Neurophysiologic tests and QST verified the subjective sensory alteration in all but 2 IAN patients, both with old injuries, and 4 LN patients who did not undergo QST. When abnormal, thermal QST showed elevation of warm and cold detection thresholds (hypo/anesthesia), hypoalgesia was less marked, and heat allodynia was only occasionally present. Contralateral thermal hypoesthesia after unilateral injury was found in 14 patients. It was associated with the occurrence of neuropathic pain (P=0.016). Axonal Abeta afferent damage was less severe in the IAN patients with pain than in those without pain (P=0.012). Neurophysiologic tests and thermal QST provide sensitive tools for accurate diagnosis of trigeminal neuropathy and study of pathophysiological features characteristic to human neuropathic pain.

Adult↗