ABSTRACT
Introducción. Los enfermos críticos pueden desarrollar cuadros de debilidad importante en la Unidad de Cuidados Intensivos (UCI). Debido a la diversidad de criterios diagnósticos utilizados, existe desacuerdo sobre el origen miopático o neuropático de este cuadro. Objetivos. Describir las alteraciones neurofisiológicas de enfermos críticos, establecer grupos de pacientes según los datos electrofisiológicos de miopatía y determinar su correspondencia con los resultados de la biopsia muscular. Pacientes y métodos. Se estudiaron prospectivamente 33 pacientes en UCI con debilidad importante, mediante electromiografía, electroneurografía y biopsia muscular percutánea. En nueve casos se amplió el estudio con estimulación muscular directa y en 14 con estimulación repetitiva. Resultados. Aplicando criterios neurofisiológicos de miopatía, se describieron tres grupos de pacientes: miopatía definida (33%), miopatía probable (46%) y miopatía incierta (21%). En la biopsia muscular, las alteraciones miopáticas más intensas, con atrofia y necrosis fibrilar, vacuolas y alteraciones miosínicas y mitocondriales, se observaron en los grupos con miopatía definida y probable (26 casos). En 17 de ellos, los potenciales de acción muscular compuestos fueron de baja amplitud y los potenciales de acción del nervio sensitivo normales. Once pacientes mostraron polineuropatía axonal sensitivomotora, que en siete de ellos se asociaba con datos de miopatía. Conclusiones. En enfermos críticos con debilidad intensa, las alteraciones miopáticas en el estudio neurofisiológico son mucho más frecuentes que la afectación neuropática. En concordancia con estos hallazgos, las alteraciones miopáticas en la biopsia muscular son manifiestas y abundantes. Los datos histopatológicos y neurofisiológicos de esta serie no sustentan una hipotética neuropatía axonal motora pura (AU)
Introduction. Critical illness patients may show marked weakness acquired in the Intensive Care Unit (ICU). There are some disagreements about the myopathic versus neuropathic damage in this condition, presumably due to the lack of reliable diagnostic criteria. Aims. To report the neurophysiological findings in critical patients, to classify them in groups according to the electrophysiological data of myopathy, and to ascertain the rapport between the neurophysiological classification of myopathy and the muscle biopsy results. Patients and methods. A prospective assessment of 33 ICU patients with marked weakness by means of needle electromyography, electroneurography, and percutaneous muscle biopsy was carried out. Direct muscle stimulation was performed in 9 patients and repetitive nerve stimulation in 14 cases. Results. According to neurophysiological criteria, patients were classified in 3 groups: definite (33%), probable (46%), and uncertain (21%) myopathy. The most conspicuous myopathic pathological findings including fibrillar atrophy and necrosis, vacuoles, and myosin and mitochondrial anomalies, were observed in both, definite and probable groups (26 patients). In 17 of these cases, low amplitude of the compound motor action potentials and normal sensory nerve action potentials were found. Axonal sensory-motor neuropathy was present in 11 patients, concomitant with neurophysiological data of myopathy in 7 cases. Conclusions. Based on the neurophysiological criteria for the assessment and classification of acquired weakness in critically ill patients, myopathy is highly predominant over the neuropathic impairment. Histopathological findings are closely related to the electrophysiological diagnosis of myopathy. Neither neurophysiological nor pathological data support a hypothetic motor axonal neuropathy in this series (AU)
Subject(s)
Humans , Muscular Diseases/diagnosis , Critical Illness , Neuromuscular Diseases/diagnosis , Biopsy , Electromyography , Electric Stimulation , Polyneuropathies/diagnosis , Muscular Diseases/etiology , Neurologic ExaminationABSTRACT
Auditory P300 event-related potential (ERP) and performance on Sustained Attention were evaluated in 24 euthymic bipolar patients and 38 healthy volunteers. There were no significant differences between groups, and performance in sustained attention had no significant influence in the P300 responses. P300 response might be driven by the presence of mood symptoms.
Subject(s)
Affect , Attention , Bipolar Disorder/physiopathology , Event-Related Potentials, P300 , Adult , Bipolar Disorder/psychology , Evoked Potentials, Auditory , Female , Humans , Male , Middle AgedABSTRACT
AIM: Two patients suffering from congenital insensitivity to pain were studied. They corresponded to types IV and V of the 'hereditary sensory and autonomic neuropathies' (HSAN) classification. CASE REPORTS: The first case showed important autonomic dysfunctions, such as anhidrosis, hyperthermia, skin and bone trophic impairment, and mental retardation; the second one only exhibited alterations in pain and temperature sensibilities. In both, chronic indolent corneal ulcers were also present. Conventional neurophysiological evaluation of the neuromuscular system was normal, but an afferent disturbance of the blink reflex (BR) was evident in both. The sympathetic skin response was absent in the HSAN type IV case and normal in the HSAN type V. Notable reduction of the small myelinated fibres, associated to almost no unmyelinated fibres in the first case, were found in the sural nerve biopsies. CONCLUSIONS: So far there haven't been described BR abnormalities in patients with congenital insensitivity to pain, which should be related to a trigeminal sensory impairment, which could explain the corneal ulcers that suffered these cases. BR studies should be included in the neurophysiological evaluation of the suspected small fibre neuropathies even when there are no facial symptoms shown.
Subject(s)
Hereditary Sensory and Autonomic Neuropathies , Pain Insensitivity, Congenital , Adolescent , Blinking/physiology , Corneal Ulcer/pathology , Female , Hereditary Sensory and Autonomic Neuropathies/classification , Hereditary Sensory and Autonomic Neuropathies/pathology , Hereditary Sensory and Autonomic Neuropathies/physiopathology , Humans , Male , Neurologic Examination , Pain Insensitivity, Congenital/pathology , Pain Insensitivity, Congenital/physiopathology , Pain MeasurementABSTRACT
Introducción. Se estudian dos casos de insensibilidad congénita al dolor que correspondían, en la clasificación de las neuropatías sensitivas autonómicas hereditarias (NSAH), a los tipos IV y V. Casos clínicos. El primer caso asociaba trastornos autonómicos muy importantes, con anhidrosis, hipertermia, lesiones tróficas cutáneas y óseas y retraso mental; el segundo sólo presentaba alteraciones muy intensas de la sensibilidad dolorosa y térmica; ambos mostraban úlceras corneales recurrentes graves. La valoración convencional neurofisiológica del sistema neuromuscular fue normal, pero en ambos casos existían anomalías en la aferencia del reflejo de parpadeo (RP); la respuesta simpática cutánea estaba abolida en el caso de la NSAH tipo IV y era normal en la NSAH tipo V. Las biopsias de nervio sural mostraban una deficiencia marcada de fibras mielínicas finas, que se asociaba a una ausencia casi completa de las amielínicas en el primer caso. Conclusiones. La alteración no descrita hasta el momento del RP en casos de insensibilidad congénita al dolor debería relacionarse con una afectación sensitiva del territorio trigeminal que, a su vez, en los casos actuales, explicaría la presencia de las úlceras corneales. El estudio del RP debería considerarse sistemáticamente en la valoración neurofisiológica de las neuropatías de fibras finas y de mediano calibre, incluso sin afectación clínica del segmento facial (AU)
Introduction. Two patients suffering from congenital insensitivity to pain were studied. They corresponded to types IV and V of the hereditary sensory and autonomic neuropathies (HSAN) classification. Case reports. The first case showed important autonomic dysfunctions, such as anhidrosis, hyperthermia, skin and bone trophic impairment, and mental retardation; the second one only exhibited alterations in pain and temperature sensibilities. In both, chronic indolent corneal ulcers were also present. Conventional neurophysiological evaluation of the neuromuscular system was normal, but an afferent disturbance of the blink reflex (BR) was evident in both. The sympathetic skin response was absent in the HSAN type IV case and normal in the HSAN type V. Notable reduction of the small myelinated fibres, associated to almost no unmyelinated fibres in the first case, were found in the sural nerve biopsies. Conclusions. So far there havent been described BR abnormalities in patients with congenital insensitivity to pain, which should be related to a trigeminal sensory impairment, which could explain the corneal ulcers that suffered these cases. BR studies should be included in the neurophysiological evaluation of the suspected small fibre neuropathies even when there are no facial symptoms shown (AU)
Subject(s)
Male , Humans , Adolescent , Female , Hereditary Sensory and Autonomic Neuropathies , Pain Insensitivity, Congenital , Neurologic Examination , Blinking , Pain Measurement , Corneal UlcerABSTRACT
INTRODUCTION: Neurophysiological monitoring in spine surgery can be performed by a number of methods, although there is no general agreement about which is the best. AIM: The aim of this study was to evaluate our experiences using the method of spinal cord stimulation with recording carried out on the peripheral nerve. PATIENTS AND METHODS: We studied 51 patients with scoliosis who were submitted to surgical correction. Stimuli were administered with the cathode located in the dorsal epidural space, two levels above the curve to be corrected, and recording was performed on the posterior tibial nerve in the popliteal fossa. RESULTS: Potential was obtained in 78% of cases, with a very low number of averages and the maximum reduction in the amplitude of the potential was found to be 33%. Spinal cord stimulation evokes muscular responses in several muscles and sensory responses in the sural nerve. None of the patients who were monitored using this method presented postoperative neurological deficits added to their previous pathology. CONCLUSIONS: The neurogenic potentials obtained by epidural spinal cord stimulation are very useful for monitoring spine surgery because they are very stable, they can be obtained quickly, they avoid the need to interfere with the anaesthetist's field and because, albeit to a small extent, they may contain information about motor pathways. The main drawback is that it is not always possible to place the electrode and that in 22% of cases we have not managed to obtain the motor component and we have therefore had to be cautious in evaluating it, since its disappearance would only give rise to a partial reduction in the potential.
Subject(s)
Electric Stimulation , Monitoring, Intraoperative/methods , Scoliosis/surgery , Spinal Cord , Adolescent , Adult , Child , Child, Preschool , Electric Stimulation/methods , Evoked Potentials , Female , Humans , Male , Middle Aged , Neurophysiology , Reaction Time , Scoliosis/physiopathologyABSTRACT
Introducción. Existen varios métodos de monitorización neurofisiológica de la cirugía de la columna, si bien no hay consenso en cuál es el mejor método para realizarla. Objetivo. Evaluar nuestra experiencia con el método de la estimulación medular con registro en el nervio periférico. Pacientes y métodos. Hemos estudiado 51 pacientes con escoliosis sometidos a corrección quirúrgica. Se aplica el estímulo con el cátodo situado en el espacio epidural dorsal, dos niveles vertebrales por encima de la curva que se va a corregir y se registra en el nervio tibial posterior en el hueco poplíteo. Resultados. Se ha obtenido un potencial en el 78 por ciento de los casos, con un número muy bajo de promedios y una disminución máxima de la amplitud del potencial del 33 por ciento. La estimulación medular evoca respuestas motoras en varios músculos, y sensitivas en el nervio sural. Ninguno de los pacientes monitorizados con este método ha presentado déficit neurológicos posoperatorios sobreañadidos a su patología previa. Conclusiones. Los potenciales neurogénicos que se obtienen mediante estimulación medular epidural son muy útiles en la monitorización de la cirugía espinal por su alta estabilidad, rapidez en su obtención, ausencia de interferencia en el campo del anestesista y porque, aun en una pequeña porción, contienen posiblemente información de vías motoras. Las desventajas son que no siempre es posible la colocación del electrodo, que en el 22 por ciento de los casos no hemos logrado obtener un registro y que hay que ser cautelosos en la valoración del componente motor, ya que su desaparición únicamente daría lugar a una reducción parcial del potencial (AU)
Introduction. Neurophysiological monitoring in spine surgery can be performed by a number of methods, although there is no general agreement about which is the best. Aim. The aim of this study was to evaluate our experiences using the method of spinal cord stimulation with recording carried out on the peripheral nerve. Patients and methods. We studied 51 patients with scoliosis who were submitted to surgical correction. Stimuli were administered with the cathode located in the dorsal epidural space, two levels above the curve to be corrected, and recording was performed on the posterior tibial nerve in the popliteal fossa. Results. Potential was obtained in 78% of cases, with a very low number of averages and the maximum reduction in the amplitude of the potential was found to be 33%. Spinal cord stimulation evokes muscular responses in several muscles and sensory responses in the sural nerve. None of the patients who were monitored using this method presented postoperative neurological deficits added to their previous pathology. Conclusions. The neurogenic potentials obtained by epidural spinal cord stimulation are very useful for monitoring spine surgery because they are very stable, they can be obtained quickly, they avoid the need to interfere with the anaesthetists field and because, albeit to a small extent, they may contain information about motor pathways. The main drawback is that it is not always possible to place the electrode and that in 22% of cases we have not managed to obtain the motor component and we have therefore had to be cautious in evaluating it, since its disappearance would only give rise to a partial reduction in the potential (AU)
Subject(s)
Male , Adolescent , Middle Aged , Humans , Adult , Child, Preschool , Child , Female , Spinal Cord , Electric Stimulation , Scoliosis , Reaction Time , Neurophysiology , Evoked Potentials , Monitoring, IntraoperativeABSTRACT
UNLABELLED: Minimal hepatic encephalopathy is often present in patients with chronic liver disease. The aim of this work was to determine changes in the dynamics of sleep electroencephalogram (EEG) in cirrhotic patients without overt encephalopathy. Twenty such cirrhotic subjects included in the protocol of hepatic transplantation of our hospital were studied and compared with 20 age-matched healthy volunteers. Spectral analysis of all-night EEG was estimated by computing the fast-Fourier transform in 2-second epochs, and averaging every 60 seconds. Artifacts were off-line suppressed, sleep stages (stage 2, stage 3-4 and REM) were determined, and the EEG mean dominant frequency (MDF) was calculated in each of these stages. Results show that in cirrhotic patients, nocturnal MDF evolution discloses a clear alteration of the ultradian EEG frequency oscillations present in controls. Also, the mean value of MDF in REM episodes was larger in cirrhotics than the corresponding value in controls. CONCLUSIONS: 1) sleep EEG evidences the existence of minimal hepatic encephalopathy; 2) the spectral analysis of EEG in minimal hepatic encephalopathy showed that the changes of MDF during sleep are an early marker of cerebral dysfunction in cirrhotic patients.
Subject(s)
Electroencephalography/methods , Hepatic Encephalopathy/physiopathology , Sleep Stages/physiology , Humans , Liver Cirrhosis/physiopathologyABSTRACT
There are no studies on event-related cognitive potentials in frontotemporal dementia (FTD). In order to evaluate the aptitude and usefulness of the event-related P300 potential in this disease, we prospectively examined 60 cases: 11 patients with FTD diagnosed according to the Lund and Manchester criteria and Neary consensus criteria, 33 patients with a probable Alzheimer's disease diagnosis following NINCDS-ADRDA criteria, and 16 normal controls. P300 latency, amplitude and reaction time were recorded using an auditory oddball paradigm. In this sample, P300 potential could be reliably performed by 10/11 FTD patients, notwithstanding their language or executive function deficiencies. The FTD group P300 mean latency was midway between the normal controls and the Alzheimer's disease group (ANOVA F(2, 74199) = 16.5; p = 0.00003). The latency range of the FTD patients were within normal values (average plus 1.96 standard deviation of the values of the control group), except for one case with a latency of 448 ms. Post hoc Newman-Keuls analysis showed that the P300 latencies of the control and FTD groups did not differ significantly (p = 0.15) and that the Alzheimer's disease group had a delayed P300 latency that differed significantly from that of the FTD (p = 0.002) and control group (p = 0.0002). However, there was overlapping in P300 latency values of the three groups. Despite these differences in latencies, the reaction time was significantly increased in the FTD and the Alzheimer's disease groups. These findings indicate that the P300 potential is less affected in patients with FTD than those with Alzheimer's disease. This fact could aid in FTD diagnosis, differential diagnosis with Alzheimer's disease and possibly its clinical management.
Subject(s)
Alzheimer Disease/physiopathology , Dementia/physiopathology , Event-Related Potentials, P300 , Evoked Potentials, Auditory , Aged , Aged, 80 and over , Alzheimer Disease/diagnosis , Analysis of Variance , Case-Control Studies , Dementia/diagnosis , Female , Humans , Male , Middle Aged , Neuropsychological Tests , Predictive Value of TestsABSTRACT
INTRODUCTION: The incidence of associate pathologies has been studied during the sleep, as well as the diagnostic efficiency of the clinical history. PATIENTS AND METHODS: Patients (n = 136) remitted by diverse services, have been studied. It has been carried out a complete polysomnography, as well as other supplementary studies (anxiety and depression tests, excessive daytime sleepiness Epworth's test, EEG and sleep notebook). RESULTS: The most common symptom turned out to be the primary snores, followed by the excessive daytime sleepiness and apneas. The results of the excessive daytime sleepiness Epworth's test and the anxiety and depression tests were not useful to differ among pathologies, not even between pathologies and patients with normal sleep. The percentage of diagnosis of suspicion confirmed by the polysomnography was of 39.7%, while in 11% of the total of patients it was observed the existence of more than a pathology of the sleep. In 49.3% of the cases the polysomnographic diagnosis was completely different from the diagnosis of suspicion. Among the patients with clinic suspicion of apnoea, in 48.3% of the cases the existence of the same one was verified, although in 14.6% it was associated with other pathologies. In 51.7% of the patients it was not possible to confirm this pathology. CONCLUSIONS: The clinical history is not enough for the diagnosis of the pathologies of the sleep. On the other hand, the existence of associate pathologies diminishes the value of several 'screening-methods'. Therefore, it is fundamental to carry out a complete polysomnography in all the patients that present any sleep disorder on the part of doctors that approach the problem of the sleep in a global way and not only thinking in the possible existence of syndrome of sleep apnoea.
Subject(s)
Medical Records , Polysomnography , Sleep Wake Disorders/diagnosis , Adolescent , Adult , Aged , Anxiety , Child , Child, Preschool , Depression , Diagnosis, Differential , Disorders of Excessive Somnolence/diagnosis , Disorders of Excessive Somnolence/epidemiology , Disorders of Excessive Somnolence/etiology , Disorders of Excessive Somnolence/physiopathology , Fatigue/etiology , Female , Hospital Departments , Humans , Male , Middle Aged , Narcolepsy/diagnosis , Narcolepsy/epidemiology , Narcolepsy/physiopathology , Psychological Tests , Severity of Illness Index , Sleep Apnea Syndromes/diagnosis , Sleep Apnea Syndromes/epidemiology , Sleep Apnea Syndromes/physiopathology , Sleep Wake Disorders/epidemiology , Sleep Wake Disorders/physiopathology , Snoring/epidemiology , Snoring/physiopathology , Spain/epidemiologyABSTRACT
Objetivos. Estudiar la incidencia de enfermedades asociadas durante el sueño, así como la eficiencia diagnóstica de la historia clínica. Se ha hecho especial hincapié en el síndrome de apnea del sueño. Pacientes y métodos. Se han estudiado 136 pacientes remitidos por diversos servicios a los que se realizó estudio polisomnográfico completo, así como otros estudios complementarios (test de ansiedad y depresión, test de Epworth, EEG de vigilia y agenda de sueño).Resultados. El síntoma más común resultó ser la roncopatía, seguida por la excesiva somnolencia diurna y las apneas. Los resultados del test de Epworth y de los tests de ansiedad y depresión no resultaron útiles para diferenciar entre patologías, ni siquiera entre patologías y personas con sueño normal. El porcentaje de diagnósticos de sospecha confirmados por la polisomnografía fue del 39,7 por ciento, mientras que en un 11 por ciento del total de pacientes se observó la existencia de más de una patología del sueño. En un 49,3 por ciento de los casos el diagnóstico polisomnográfico resultó por completo distinto del diagnóstico de sospecha. Entre los pacientes con sospecha clínica de apnea, en un 48 por ciento de los casos se verificó la existencia de la misma, aunque en un 15 por ciento estaba asociada con otras enfermedades. En un 51,7 por ciento de los pacientes no se confirmó la patología. Conclusiones. La historia clínica por sí sola no resulta suficiente para el diagnóstico definitivo de las patologías del sueño. Por otro lado, la existencia de patologías asociadas disminuye considerablemente el valor de numerosos métodos de cribado. Por lo tanto, es fundamental realizar un estudio polisomnográfico completo en todos los pacientes que presenten cualquier trastorno del sueño por parte de médicos que aborden el problema del sueño de forma global, y no sólo pensando en la posible existencia de síndrome de apnea del sueño (AU)
Subject(s)
Middle Aged , Child, Preschool , Child , Adult , Adolescent , Aged , Male , Infant , Infant, Newborn , Female , Humans , Polysomnography , Magnetic Resonance Imaging , Medical Records , Sleep Wake Disorders , Snoring , Spain , Sleep Apnea Syndromes , Narcolepsy , Anxiety , Diagnosis, Differential , Depression , Hospital Departments , Disorders of Excessive Somnolence , Leukomalacia, Periventricular , Fatigue , Severity of Illness Index , Psychological TestsABSTRACT
OBJECTIVE: To evaluate lymphocyte subpopulations after a first pregnancy in women who had normal pregnancies and in those whose pregnancies terminated in spontaneous abortion. STUDY DESIGN: Sixty healthy, nonpregnant women in three groups were studied: 20 with a prior abortion, 20 with a prior normal pregnancy and 20 nulligravid. Peripheral blood lymphocytes were studied using monoclonal antibodies and flow cytometry. Women were followed for one year, and if they became pregnant again, pregnancy complications were recorded. RESULTS: The percentage of B lymphocytes was significantly decreased in the postpartum group (6% +/- 2.22) in comparison to nulligravid women (8.7% +/- 3.37) (P = .005). The percentage of CD4 lymphocytes was significantly higher in the postabortion group (44.7% +/- 7.81) in relation to the control group (39.85% +/- 6.01) (P = .03). A significantly higher CD4/CD8 ratio was found in the postabortion group in relation to the control group (1.65 vs. 1.24) (P = .01). Women with pregnancy complications in their next pregnancy had a lower absolute value for total lymphocytes (P = .02), T lymphocytes (P = .04), absolute CD8 lymphocytes (P = .01) and percentage of CD8 lymphocytes (P = .02) and a higher percentage of CD4 lymphocytes (P = .03) and higher CD4/CD8 ratio (P = .02) than women who had not experienced any pregnancy complications. CONCLUSION: The percentage of B lymphocytes was lower in normal primipara in comparison to women who had never been pregnant. Women with previous spontaneous abortions had an immunologic profile expected in a rejection phenomenon; that result was more marked if they went on to experience complications in their next pregnancies.
Subject(s)
Abortion, Spontaneous/immunology , B-Lymphocyte Subsets/immunology , Adult , CD4-CD8 Ratio , Cohort Studies , Female , Humans , Parity , Pregnancy , Pregnancy OutcomeABSTRACT
INTRODUCTION: Recently a series of cases has been reported characterized by myoclonic crises similar to those occurring in benign myoclonic epilepsy of childhood. However, these crises only occurred after unexpected tactile or auditory stimuli. These clinical conditions represent a new epileptic syndrome, which is age-dependent and has been called benign myoclonic epilepsy of childhood. CLINICAL CASE: We present the case of a 12 month old girl with myoclonic crises which occurred only after auditory or tactile stimuli. The myoclonia could be set off whilst awake or asleep. No other types of crises or neurological changes were seen. A brother of the patient had had febrile convulsions. The EEG recorded during the crises showed generalized brief spike-and-wave discharges at 3 cycles/second. The intercritical EEG was normal whilst awake, but during sleep showed brief generalized discharges. After treatment with valproate was started the crises became less frequent. CONCLUSIONS: The case we describe is similar to those described by Ricci et al in 1995. We, therefore, consider it to fit the concept of reflex myoclonic epilepsy of childhood of benign character. We consider that this condition should be differentiated from other reflex epilepsies and epileptic syndromes with a predominance of myoclonia, including benign myoclonic epilepsy of childhood.
Subject(s)
Epilepsies, Myoclonic , Epilepsy, Reflex , Acoustic Stimulation , Aortic Coarctation/complications , Aortic Coarctation/surgery , Electroencephalography , Epilepsies, Myoclonic/diagnosis , Epilepsies, Myoclonic/etiology , Epilepsies, Myoclonic/genetics , Epilepsy, Reflex/diagnosis , Epilepsy, Reflex/etiology , Epilepsy, Reflex/genetics , Face , Female , Humans , Infant , Male , Seizures, Febrile/genetics , Sleep Wake Disorders/diagnosis , Sleep Wake Disorders/etiology , Sleep Wake Disorders/genetics , TouchABSTRACT
INTRODUCTION: The study of motor unit potentials (MUP) may be carried out using qualitative or quantitative methods. The considerable usefulness of quantitative methods in the diagnosis of neuromuscular disorders has led to development of new automatic techniques which permit greater speed and accuracy of clinical investigation. In this review we consider traditional electromyographic techniques and describe some automatic methods. DEVELOPMENT: Qualitative techniques are simpler but give limited information since they only permit recording of very marked alterations. The introduction of trigger and averaging permit quantitative analysis and thus the evaluation of less obvious changes. Although they do not identify all the potentials of an electromyographic signal, the new automatic techniques using partial decomposition avoid the loss of time occurring with earlier techniques, give reliable objective measurements of the MUP and also the possibility of measuring new parameters, such as the area or frequency of discharge. CONCLUSIONS: New methods of evaluation of the MUP have significant advantages over traditional methods, namely increased speed and objectivity. However, this makes it necessary to redefine normal values since different methods are used for obtaining and processing the signals, otherwise the results may not be strictly comparable.
