[Bilateral vitreous haemorrhage associated with pontomesencephalic haemorrhage: an extreme case of Terson syndrome]. / Hemorragia vitrea bilateral asociada a hemorragia pontomesencefalica: un caso extremo de sindrome de Terson.

TITLE: Hemorragia vitrea bilateral asociada a hemorragia pontomesencefalica: un caso extremo de sindrome de Terson.

Miopatía del enfermo crítico. Valoración neurofisiológica y biopsia muscular en 33 pacientes / Critical illness myopathy. Neurophysiological and muscular biopsy assessment in 33 patients

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)

[Modified aspiration needle muscular biopsy in neuromuscular diseases. Use and advantages over open surgical biopsy]. / Estudio de las enfermedades neuromusculares por biopsia percutánea mediante aguja con aspiración modificada. Utilidad y ventajas sobre la biopsia quirúrgica.

OBJECTIVE: To evaluate aspiration needle muscular biopsy as an alternative to surgical open biopsy, so we focus on its results and tolerance. PATIENTS AND METHODS: We studied 150 patients with muscular pathology of every kind, and aged between 10 and 86 years, using a modified Allendale/Liverpool needle which by our indication has a built-in lateral funnel that provides faultless aspiration in 100% of cases. Percutaneous biopsy neuromuscular disorders study with modified aspiration Allendale needle: use and advantages over surgical biopsy. RESULTS: The biopsy, which was very well tolerated by the patients, children in particular, left no scar and produced fine samples for standard, immunohistochemical, ultrastructural, biochemical and genetic investigation. In children beyond 10 years of age no general anesthetics was required and in many 4-10 years neither. A number of unsuspected cases of mitochondrial or inflammatory myopathy were detected. Patients with cramps or unclearly defined clinical picture did, however, show frequent morphological pathology. In just three cases samples were defective; all others produced changes of diagnostic or prognostic value with 8% without morphologically abnormal changes. CONCLUSIONS: Modified aspiration needle biopsy is the choice method to study muscle. The samples are of excellent quality allowing for any kind of morphological, biochemical or genetic investigation. The procedure is routinely very well tolerated by patients so is very superior to open surgical biopsy, that we still use for infants in selected cases.

Estudio de las enfermedades neuromusculares por biopsia percutánea mediante aguja con aspiración modificada. Utilidad y ventajas sobre la biopsia quirúrgica / Modified aspiration needle muscular biopsy in neuromuscular diseases. Use and advantages over open surgical biopsy

Introducción. La biopsia muscular percutánea es una alternativa a la biopsia quirúrgica abierta; intentamos evaluar sus ventajas y resultados. Pacientes y métodos. Se estudiaron 150 pacientes entre 10 y 86 años empleando de una aguja con aspiración de tipo Allendale/Liverpool, con una embocadura lateral para efectuar la aspiración. Los pacientes presentaban cuadros diversos de patología muscular. Resultados. La tolerancia es muy buena, y en niños de edad inferior a 10 años, muy a menudo, no se requiere anestesia general. No queda cicatriz y el material es suficiente para el estudio morfológico, histoquímico, citoarquitectural, bioquímico y genético. De todos los casos, solamente en tres las tomas no fueron valorables; el resto de las tomas aportaron información diagnóstica y pronóstica, o no específica pero pronóstica, y en un 8 por ciento fueron normales. Se han detectado numerosos casos de miopatía inflamatoria o mitocondrial no sospechados clínicamente. Los grupos de pacientes con sintomatología mal definida y calambres muestran una elevada tasa de patología subyacente. Conclusión. Los resultados muestran que la biopsia por aguja con aspiración con la modificación sugerida por nosotros es el procedimiento de elección para el estudio del músculo; produce un material que permite un estudio morfológico completo y fiable, así como estudios bioquímicos y genéticos, con una mínima molestia, y, en conjunto, es claramente ventajosa sobre la biopsia quirúrgica, que nosotros reservamos para casos aislados en niños muy pequeños (AU)

Objective. To evaluate aspiration needle muscular biopsy as an alternative to surgical open biopsy, so we focus on its results and tolerance. Patients and methods. We studied 150 patients with muscular pathology of every kind, and aged between 10 and 86 years, using a modified Allendale/Liverpool needle which by our indication has a built-in lateral funnel that provides faultless aspiration in 100% of cases. Percutaneous biopsy neuromuscular disorders study with modified aspiration Allendale needle: use and advantages over surgical biopsy. Results. The biopsy, which was very well tolerated by the patients, children in particular, left no scar and produced fine samples for standard, immunohistochemical, ultrastructural, biochemical and genetic investigation. In children beyond 10 years of age no general anesthetics was required and in many 4-10 years neither. A number of unsuspected cases of mitochondrial or inflammatory myopathy were detected. Patients with cramps or unclearly defined clinical picture did, however, show frequent morphological pathology. In just three cases samples were defective; all others produced changes of diagnostic or prognostic value with 8% without morphologically abnormal changes. Conclusions. Modified aspiration needle biopsy is the choice method to study muscle. The samples are of excellent quality allowing for any kind of morphological, biochemical or genetic investigation. The procedure is routinely very well tolerated by patients so is very superior to open surgical biopsy, that we still use for infants in selected cases (AU)

[Hereditary sensory and autonomic neuropathies. The neurophysiological and pathological aspects of two cases with congenital insensitivity to pain]. / Neuropatías sensitivas autonómicas hereditarias. Dos casos con insensibilidad congenita al dolor; aspectos neurofisiológicos y patológicos.

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.

Neuropatías sensitivas autonómicas hereditarias. Dos casos con insensibilidad congénita al dolor: aspectos neurofisiológicos y patológicos / Hereditary sensory and autonomic neuropathies. The neurophysiological and pathological aspects of two cases with congenital insensitivity to pain

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 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 (AU)

Long term follow up of a hemimasticatory spasm.

OBJECTIVES: To describe the clinical and neurophysiological findings in a case of hemimasticatory spasm (HMS) followed during 14 years of evolution. MATERIAL AND METHODS: A woman suffered from very frequent paroxysmal episodes of painful involuntary occlusion of the jaw. Neurophysiological studies were performed at the 3, 12 and 14 years after the onset of symptoms. They included a needle electromyographic (EMG) evaluation of the main jaw closing and opening muscles, the jaw reflex (JR), the masseteric silent period (MSP) and the masseteric inhibitory reflex (MIR). RESULTS: Clinical symptoms remained unchanged throughout the period of observation. Conventional EMG never disclosed neurogenic signs. Voluntary closure of the jaw systematically provoked an abnormal activity with muscle cramps characteristics, restricted to the left masseter muscle. Left JR response was normal in the first evaluation and became delayed and of reduced amplitude in the second. The MSP and MIR were abolished on the left side during the spasmodic episodes whereas they were strictly normal out of them. The MIR abnormalities showed the characteristic pattern of an efferent lesional type. CONCLUSIONS: Hemimasticatory spasm probably is the consequence of an abnormal trigeminal hyperexcitability likely induced by the demyelinating lesion of its peripheral motor pathway. The main neurophysiological abnormalities may persist unmodified over a long course of the disease and allow the differential diagnosis of HMS from oromandibular dystonia and temporomandibular dysfunction (TMD).

[Segmental motor paralysis caused by the varicella zoster virus. Clinical study and functional prognosis]. / Parálisis motora segmentaria por virus varicela-zoster. Estudio clínico y pronóstico funcional.

INTRODUCTION: Segmental motor paralysis of the limbs (SMP) complicates 2-3% of the cases of cutaneous herpes zoster. Viral invasion and inflammation of the motor neurons of the anterior horn cells by the varicella-zoster virus (VVZ) causes clinical weakness at the same time and site as the cutaneous eruption. OBJECTIVES: To analyze the clinical findings, complementary investigations and functional prognosis of patients with SMP at brachial plexus and lumbosacral levels. PATIENTS AND METHODS: We made a retrospective study of 10 patients with SMP admitted to the Hospital Universitario Gregorio Maranon de Madrid during 1989-1999, aged between 38 and 84 years (6 women, 4 men). Neurological examination was done, including muscle balance, complementary studies including microbiology (serum and CSF serology, viral PCR-ADN), neurophysiology using MNR of the spine and plexuses and functional prognosis on the NDS, NSS and RANKIN scales. RESULTS: There is a close relationship between dermatome and myotome involvement (90%). The brachial and lumbosacral plexuses were equally affected (50%). Plasma and CSF VVZ serology was positive in 50% of the cases, permitting diagnosis of a patient with no cutaneous lesions (zoster sine herpete). Denervation of the myotomes involved and the paraspinal muscles was shown on neurophysiological studies. In most cases there was functional improvement, with complete functional recovery in 80% of the cases after 12 months. CONCLUSIONS: VVZ should be considered amongst the aetiologies of SMP, even in the absence of cutaneous lesions (zoster sine herpete). The SMP coincides in time and place with the dermatome lesions. In most patients there is complete functional recovery within 12 months.

Parálisis motora segmentaria por virus varicela-zoster. Estudio clínico y pronóstico funcional / Segmental motor paralysis due to varicella-zoster virus. A clinical and functional prognosis study

Introducción. La parálisis motora segmentaria en miembros (PMS) complica el 2-3 por ciento de los casos de herpes zoster cutáneo.La invasión vírica y la inflamación de las motoneuronas del asta anterior por el virus varicela-zoster (VVZ) provoca un cuadro de debilidad coincidente en tiempo y distribución con la erupción cutánea.Objetivos. Analizar los hallazgos clínicos, exploraciones complementarias y pronóstico funcional en los pacientes con PMS en plexos braquial y lumbosacro. Pacientes y métodos. Se han estudiado retrospectivamente 10 pacientes afectados de PMS, ingresados en el Hospital General Universitario Gregorio Marañón de Madrid (España) entre 1989 y 1999, con edades comprendidas entre 34-84 años (6 mujeres y 4 varones). Se realizó exploración neurológica con balance muscular, estudios complementarios con microbiología (serología en suero y líquido cefalorraquídeo (LCR), reacción en cadena de la polimerasa-ADN vírico), neurofisiología, neuroimagen con resonancia magnética espinal y de plexos, y pronóstico funcional mediante las escalas Neurological Disability Scale (NDS), Neurological Symptom Score (NSS) y Rankin. Resultados. Existió una estrecha relación entre la afectación dermatómica y la miotómica (90 por ciento). La afectación fue proporcional en plexos braquial y lumbosacro (50 por ciento). La serología para VVZ fue positiva en suero y LCR en el 50 por ciento de los casos; este hecho permitió el diagnóstico en un paciente sin lesiones cutáneas (zoster sine herpete). En el estudio neurofisiológico existía desnervación en miotomas afectos y musculatura paraespinal. La evolución funcional fue favorable en la mayoría de los pacientes, con recuperación funcional completa en el 80 por ciento de los casos en 12 meses.Conclusiones. Debemos considerar al VVZ dentro de las etiologías de la PMS, incluso en ausencia de lesiones cutáneas (zoster sine herpete). La PMS coincide en tiempo y localización con las lesiones dermatómicas. La recuperación funcional es completa en la mayoría de los pacientes al cabo de 12 meses (AU)

[Multifocal motor neuropathy]. / Neuropatía motora multifocal.

INTRODUCTION: The multifocal motor neuropathy is an immunological disease that courses with an asymmetrical distal weakness, usually predominant in the upper limbs. DEVELOPMENT AND CONCLUSIONS: It is not rarely misdiagnosed as a motoneurone disease because of the frequent occurrence of fasciculations and cramps and the absence of sensory symptoms. Neurophysiological studies are essential for the proper diagnosis, disclosing the presence of conspicuous alterations of the nerve conduction that are mainly of demyelinating type and occur exclusively in the motor fibers. The nerve conduction blocks characteristically found in this disease are long lasting, multifocal but preferentially proximal, and they are out of the typical levels of the compression neuropathies. High titers of IgM antibodies, mainly anti-GM1, are frequently observed although their pathogenetic significance has not still been completely established. In many cases, even in those with very prolonged evolutions, treatment with high doses of parenteral immunoglobulins has been effective.

Neuropatía motora multifocal / Multifocal motor neuropathy

Introducción. La neuropatía motora multifocal es una enfermedad de origen inmunológico, que cursa habitualmente con debilidad distal, asimétrica, de predominio en miembros superiores. Desarrollo y conclusiones. Su afectación exclusiva o muy predominante motora, con grados variables de atrofia muscular, y la presencia muy frecuente de fasciculaciones y calambres hacen que se confunda fácilmente con una enfermedad de motoneurona. Sin embargo, el estudio electrofisiológico es determinante para el diagnóstico, ya que demuestra la existencia de trastornos en las conducciones nerviosas periféricas de carácter desmielinizante, entre los que destacan los bloqueos de conducción, que afectan de forma exclusiva a los axones motores. Son además bloqueos multifocales, persistentes, localizados preferentemente en niveles proximales y fuera de los puntos típicos de compresión nerviosa. Es frecuente la presencia de anticuerpos antigangliósidos, especialmente IgM anti-GM1, aunque no se conoce con certeza el papel real que desempeñan en la patogenia de la enfermedad. El tratamiento con inmunoglobulinas intravenosas se ha mostrado altamente eficaz y ha provocado mejorías clínicas, incluso en casos de muy larga evolución (AU)

Blink reflex recovery cycle in patients with blepharospasm unilaterally treated with botulinum toxin.

To determine whether Botulinum Toxin Type A (BTXA) has an effect on the Central Nervous System, the authors studied the excitability of the blink reflex recovery cycle in 12 patients with blepharospasm before and 3 weeks after unilateral BTXA injections. To avoid recording from severely denervated muscles, the R2 response of the blink reflex was obtained from the untreated orbicularis oculi with both ipsilateral and contralateral supraorbital nerve stimulation. Baseline recovery curves were compared with a control group (n = 11) and showed an enhanced recovery of the R2 component. There were no significant differences between the recovery curves of the R2 component of the blink reflex taken before BTXA treatment and those taken after treatment. This finding confirms that BTXA does not modify the excitability of brainstem interneurons that mediate the bilateral R2 response of the blink reflex in patients with blepharospasm.

[Ischemic neuropathy with conduction blocks]. / Neuropatía isquémica con bloqueos de conducción.

We present a patient with a clinical picture of multiple mononeuropathy in which muscle and sural nerve biopsy revealed the existence of vasculitis compatible with panarteritis nodosa. Along with classical axonal lesion signs, we observed multifocal conduction blocks (CB) in all the nerves explored electrophysiologically. Topographic evolution was atypical in that distal BC disappeared earlier, whereas proximal BC appeared later and in all cases persisted longer. Ischemia may play a pathogenic role in BC along with other more well-known factors such as compression and immunological processes. BC detection would probably be less exceptional if, when ischemic neuropathy is suspected, patients were subjected to early and follow-up electrophysiological exploration that included proximal nerve segments.

Fasciculation-myokymic activity and prolonged nerve conduction block. A physiopathological relationship in radiation-induced brachial plexopathy.

Fourteen radiation-induced brachial plexus neuropathies in 12 patients suffering from cancer were studied. Neurophysiological evaluation showed a diffuse neurogenic lesion with muscular denervation signs associated with motor and sensory nerve conduction impairment of axonal type in the distal segments of the arm. Somatosensory evoked potentials were frequently abnormal, with absence of N9 in 9 out of the 10 extremities explored. The most characteristic findings were, however, the presence of fasciculation potentials--single and grouped--and myokymic discharges in 78.5% of cases (11 out of 14 plexuses), and a motor nerve conduction block on proximal stimulation, at the supraclavicular as well as cervical spine levels, in all of the cases. Both phenomena showed a high correlation when analyzed in the same neuromuscular territory. The 5 muscles with no voluntary activity and complete--or nearly complete--motor nerve conduction block were the ones with the most intense ectopic activities. The conduction blocks were present after long periods of illness in all cases and, in 2 of the cases, they persisted in successive explorations at intervals of 9 months and 2 years respectively. These data would support a probable cause-effect relationship between a persistent and prolonged motor nerve conduction block and the presence of fasciculation-myokymic type activities. One could even postulate that the infrequent neuropathies, in which both findings have been described as relevant features, have a similar physiopathological mechanism.

[Motor neuropathy with conduction blocks]. / Neuropatía motora con bloqueos de conducción.

A series of 4 patients with pure, chronic and progressive motor neuropathy whose main clinical characteristics were asymmetric and distal weakness of the upper limbs, myokymia and fasciculations is presented. There were no sensory impairment and amyotrophy was observed in only one case. This picture suggested the diagnosis of motor neuron disease (MND). However, neurophysiologic examination demonstrated the presence of multifocal conduction blocks (CB) of the motor axons which were preferentially located in the proximal nerve segments and always at points atypical to nerve compression. The peripheral sensitive conductions and the somatosensory evoked potentials were normal, even through the nerve segments where the CB were located. Since this is a treatable potentially reversible syndrome, this motor neuropathy with CB should be included in the differential diagnosis of MND.

[Brainstem lesion in multiple sclerosis, blink reflex, and brainstem auditory evoked potentials]. / Lesión troncoencefálica en la esclerosis múltiple, reflejo de parpadeo y potenciales evocados auditivos troncoencefálicos.

Blink reflex (BR) and brainstem auditory evoked potentials (BAEP) were recorded from 168 patients with several diagnostic categories of multiple sclerosis, from which 98 complained brainstem symptoms (BSS+). From the whole group, the BR showed a higher degree of abnormality (45.75%) than BAEP (27.95). This range increased in the group BSS+ (52.15% for the BR and 34.9% for the BAEP) and even more when sings or symptoms of brainstem were present at the time of exploration (BSS+P) 60.4% for the BR and 41.3% for BAEP. Among patients who never complained brainstem symptoms, the BR disclosed a subclinical lesion in the 33.3% and the BAEP in the 16.9%. The combination of BR and BAEP were more useful than an isolated test. The localization of the lesion both clinically and in the BR were mostly on the pons. Light correlation between the presence of isolated or multiple symptoms and the disorder in the BR were present. Facial myokymia and internuclear ophthalmoplegia were most often associated with disorder in the BR, in both, the commonest localization was on the pons, and in the former about the motor nucleus of the facial nerve.

[The electroretinogram and visual evoked potentials in patients with Parkinson's disease]. / Electrorretinograma y potenciales evocados visuales en pacientes con la enfermedad de Parkinson.

Whether Parkinson's disease patients have been shown to have abnormal visual evoked cortical potentials (VEPs) to flash and pattern stimulation or not, is a matter widely discussed. Actually it is said that this variability may be due to the stimulus method used and how the patients were selected. The retina is rich in dopamine and together with previous animal and human studies, this suggests that the abnormal VEPs in Parkinson's disease patients may be due to a biochemical and electrophysiological disorder in the retina. This hypothesis has been examined by studying the flash VEPs, pattern VEPs and with light electroretinogram in 29 Parkinson's disease patients and matched control subjects. We have found: a) Slower FVEPs and PEVPs latencies in Parkinson disease patients. Flash VEPS were more frequently abnormal than pattern VEPs. We have only found a significant relationship between slow flash VEPs and the patient age. b) Electroretinograms waves (a) and (b) amplitudes were smaller in Parkinson disease patients than in control subjects. b/a coefficient abnormal values must be due basically to wave (a) alterations. These values are statistically significant with respect to the number of years of L-Dopa in the evaluative stage and the evolutive stage of the illness. For all these reasons, we can deduce that an anomaly exists in the dopaminergic pathway in the retina, localized in the plexiform layer and neurophysiologically detectable by a study of the wave variations of the ERG and of the b/a coefficient.

[Post-radiation brachial plexus disease. Clinical and neurophysiological study]. / Plexopatía braquial postradiación. Estudio clínico y neurofisiológico.

Nine patients who developed 11 brachial plexopathies after a radiation therapy for cancer have been studied. They clinically showed heterogeneity in the common criteria used to establish the differential diagnosis between post-radiation and tumoral brachial plexopathies (PRBP and TBP) and specially within the period free of symptoms from the end of radiation, and the presence and intensity of pain. Neurophysiological studies showed a diffused neurogenic lesion with muscular denervation associated to motor and sensory nerve conduction impairment on proximal segments of the arm. Somatosensory evoked potentials were frequently abnormal with absence of N9 potential in 6 out of 7 explored plexuses. The most characteristic findings were, however, the presence of fasciculation potentials and myokymic discharges in 73 per cent of cases, and the motor nerve conduction blocking with proximal -supraclavicular and cervical spine- stimulation in all of them. Both of these phenomena, when analyzed in the same neuromuscular territory, were highly correlated, supporting a probable causal relationship. The neurophysiological data may contribute to the proper differentiation between brachial plexopathies of radiation or tumoral origin. The also would permit to consider a similar physiopathological basis of PRBP with some other infrequent neuropathies where they have been described as relevant features.