RESUMO
Angiographic Moyamoya is a rare cerebrovascular disease most frequent in asia. Its characateristics are recurrent ischemic attacks due to progressive occlusion of ICA branches. Angiography reveals fine arterial collateralisation reminding of ascending smoke ("moyamoya" in japanese). Neurosurgical treatment strategies include direct and indirect reanastomosation procedures. Randomised trials for comparison of clinical outcome and long term survival remain missing. A 23 years old female with glycogenosis type IA was first diagnosed bilateral angiographic moyamoya with bilateral proximal stenosis of ICA after transient ischemic attack (TIA). Coincidence of both rare diseases moyamoya and glycogenosis has previously been reported in three cases, so that this metabolic dysfunction presumably is a true risk factor for moyamoya. In our case, excellent angiographic and functional results were achieved by bilateral, consecutive Enzephalo-Duro-Arterio-Myo-Synangiosis (EDAMS).
Assuntos
Doença de Depósito de Glicogênio Tipo I/complicações , Doença de Depósito de Glicogênio Tipo I/patologia , Doença de Moyamoya/complicações , Doença de Moyamoya/patologia , Procedimentos Neurocirúrgicos , Procedimentos Cirúrgicos Vasculares , Artéria Carótida Interna/patologia , Estenose das Carótidas/patologia , Angiografia Cerebral , Feminino , Doença de Depósito de Glicogênio Tipo I/cirurgia , Humanos , Ataque Isquêmico Transitório/complicações , Ataque Isquêmico Transitório/patologia , Angiografia por Ressonância Magnética , Doença de Moyamoya/cirurgia , Neovascularização Patológica/patologia , Neovascularização Patológica/terapia , Adulto JovemRESUMO
McLeod syndrome is an Xp21-linked Kell blood group variant due to lack of erythrocyte protein Kx with associated RBC membrane dysfunction such as acanthocytosis. A man with this syndrome developed chorea and slight neuropsychological impairment. He had caudate atrophy on cerebral imaging and reduced striatal dopamine D2-receptor binding on single-photon emission computed tomography. Since Xp21 was partly deleted in the patient, the missing gene product (possibly Kx) may be essential for the integrity of the striatum.
Assuntos
Encéfalo/fisiopatologia , Ligação Genética , Sistema do Grupo Sanguíneo de Kell/genética , Cromossomo X , Benzamidas , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Meios de Contraste , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Pirrolidinas , Síndrome , Tomografia Computadorizada de Emissão de Fóton Único , Tomografia Computadorizada por Raios XRESUMO
Anti-acetylcholine receptor (AChR) antibodies in myasthenia gravis (MG) can be quantitated using AChR extracted from the human rhabdomyosarcoma cell line TE671 (AChRTE671) as a practical alternative to AChR from human amputated limbs (AChRAMP). We compared the two antigen preparations using serum samples from different clinical groups of MG patients (n = 112) and various controls (n = 189). With two exceptions, both tests were positive or negative in the same patients. However, in the generalized MG group, the TE671 assay yielded significantly lower titers than the AChRAMP assay.
Assuntos
Autoanticorpos/análise , Miastenia Gravis/imunologia , Receptores Colinérgicos/imunologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Linhagem Celular , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Four patients with tumours involving or compressing the brain stem are described whose initial clinical symptoms of fluctuating paresis of the external ocular muscles and/or the pharyngeal muscles without other neurological deficits led to the primary diagnosis of focal myasthenia. The combination of an unusual clinical pattern, involvement of muscles of only one ocular nerve or severe dysphagia/dysarthria without extension of the myasthenic symptoms, should lead to further investigation to exclude other reasons of a focal myasthenic syndrome such as a brain-stem tumour.
Assuntos
Neoplasias Encefálicas/diagnóstico , Tronco Encefálico , Oftalmopatias/etiologia , Miastenia Gravis/diagnóstico , Adulto , Idoso , Astrocitoma/diagnóstico , Neoplasias Encefálicas/complicações , Tronco Encefálico/diagnóstico por imagem , Tronco Encefálico/patologia , Diagnóstico Diferencial , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Papiloma/diagnóstico , Tomografia Computadorizada por Raios XRESUMO
A case of complete bilateral internal ophthalmoplegia as the sole clinical sign of botulism is reported. Diagnosis was immediately confirmed by single-fibre electromyography (SFEMG), which revealed abnormally high blocking (14.3%), contrasting with moderately increased jitter (mean consecutive difference in the extensor digitorum communis muscle, 43.9 microseconds). After giving equine botulinum antitoxin and simultaneous forced emptying of the bowels, ocular symptoms completely disappeared within 2 days. Six days, 5 weeks and 6 months after the first SFEMG study, the jitter was still abnormal, even becoming more so with time. Blocking, however, was only rarely observed in the follow-up studies. It is concluded that SFEMG may serve as a useful and sensitive method for the rapid diagnosis of botulinum intoxication, even in cases where no clinical signs of general muscular weakness are apparent.
Assuntos
Botulismo/diagnóstico , Oftalmoplegia/fisiopatologia , Adulto , Eletromiografia/métodos , Humanos , MasculinoRESUMO
McLeod syndrome was originally described on the basis of a specific blood group phenotype with weak expression of Kell antigens. This erythrocyte abnormality also causes acanthocytosis. The haematological findings are associated with abnormalities in other organ systems, including neuromuscular manifestations. A 51-year-old patient was followed up for 11 years. He presented with persistent muscle creatine kinase elevation and progressive heart disease and later developed a slowly progressive neuropathy and choreic movements. His younger brother presented with grand mal seizures, involuntary movements and high muscle creatine kinase when aged 43 years. Clinical myopathy was absent in both, yet muscle biopsy showed mild myopathic changes. The presence of a motor axonopathy was supported by electrophysiological findings. One brother also showed sensory axonopathy. The movement disorder suggested accompanying basal ganglia dysfunction. Earlier reports of McLeod syndrome are reviewed with respect to neuromuscular involvement. Absence of the Kx membrane protein seems to be the cause of this multi-system disorder.
Assuntos
Sistema do Grupo Sanguíneo de Kell/genética , Transtornos dos Movimentos , Doenças Neuromusculares , Taquicardia , Acantócitos , Adulto , Creatina Quinase/análise , Família , Ligação Genética , Humanos , Masculino , Pessoa de Meia-Idade , Transtornos dos Movimentos/sangue , Músculos/química , Doenças Neuromusculares/sangue , Síndrome , Taquicardia/sangue , Cromossomo XRESUMO
The purpose of the study was to describe typical MRI findings in various types of idiopathic inflammatory myopathies in adulthood and to correlate the MRI with histopathological and electromyographic findings, and the serum creatine kinase (CK) activity. A third goal was to assess the diagnostic value of the use of gadolinium-DTPA (Gd-DTPA). Fifty-eight patients (35 women, 23 men), aged 21-83 years (median age 59 years), suffering from idiopathic myositides (13 with acute and 45 chronic diseases; 25 with polymyositis, 14 with dermatomyositis, 8 with granulomatous and 11 with inclusion body myositides) were examined with MRI. Seventeen of them received an intravenous infusion of Gd-DTPA. Histopathological and MRI findings of 21 muscles of 18 patients were compared. MRI of skeletal muscles showed abnormal signal intensities in 56 (96.6%) of the 58 patients. MRI abnormalities were found more often than elevated CK activity (P < 0.001). The hyperintensity of T2-weighted images was more conspicuous than on T1-weighted images in 26 (44.8%) patients, indicating oedema-like abnormalities. MRI of 50 (86.2%) patients showed fat replacement. In acute myositides, oedema-like abnormalities were more often visible and in muscle lipomatosis less often visible than in chronic diseases (P < 0.05 each). In dermatomyositis oedema-like abnormalities were more and lipomatosis less frequent than in the other types of myositis (P < 0.005) and correlated with the acuteness of the disease.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Imageamento por Ressonância Magnética , Músculos/patologia , Miosite/diagnóstico , Adulto , Idoso , Idoso de 80 Anos ou mais , Creatina Quinase/sangue , Dermatomiosite/diagnóstico , Edema/patologia , Eletromiografia , Feminino , Gadolínio DTPA , Granuloma/diagnóstico , Humanos , Corpos de Inclusão/ultraestrutura , Lipomatose/diagnóstico , Masculino , Pessoa de Meia-Idade , Compostos Organometálicos , Ácido Pentético/análogos & derivados , Sensibilidade e EspecificidadeRESUMO
Calf hypertrophy is a typical clinical feature in neuromuscular diseases such as X-linked muscular dystrophies of Duchenne and Becker type and can be seen as an atypical feature in numerous other diseases. The diagnosis of calf hypertrophy usually is based on subjective visual assessment. The aim of this prospective study was to examine the prevalence of calf hypertrophy in a large number of patients with various neuromuscular diseases based on quantitative ultrasound measurement of calf muscle thickness. Additionally, true and pseudohypertrophy should be distinguished according to the absence or presence of abnormal muscle echointensities caused by infiltration of fat tissue. Fifty adult normal controls and 350 patients with various neuromuscular diseases were investigated. Absolute calf hypertrophy was diagnosed if the combined thickness of the gastrocnemius and soleus muscles exceeded the mean value of the control persons by at least 3.0 standard deviations (SD). Relative calf hypertrophy was diagnosed when the ratio of the combined thicknesses of the gastrocnemius and soleus muscles divided by the combined thicknesses of the rectus femoris and vastus intermedius muscles lay at least 3.0 SD below the mean value of the controls. Pseudohypertrophy was present if the echointensities of the gastrocnemius and soleus muscles reached or exceeded 3.0 SD above the mean value of the controls. An absolute hypertrophy of the calves was detected in 80 patients (= 22,9%; 64 true and 16 pseudohypertrophies), 16 patients exhibited a relative hypertrophy of the calves (= 4.6%; 12 true and 4 pseudohypertrophies). A significantly increased portion of both absolute calf hypertrophies and pseudohypertrophies as compared to the control group were found in juvenile proximal spinal muscular atrophy type 3, central core disease, centronuclear myopathy, benign X-linked muscular dystrophy of Becker type, autosomal recessive limb girdle muscular dystrophy, acid maltase deficiency, polymyositis, and granulomatous myositis. A significantly increased number of relative calf hypertrophies was present in juvenile proximal spinal muscular atrophy type 3, facioscapulohumeral muscular dystrophy, and inclusion body myositis. In the majority of the diseases included in the study, calf hypertrophy occurred in at least some patients. In conclusion, calf hypertrophy is a frequent and unspecific clinical feature in many neuromuscular diseases. Ultrasound is a convenient method for the exact definition of calf hypertrophy.
Assuntos
Músculo Esquelético/diagnóstico por imagem , Músculo Esquelético/patologia , Doenças Neuromusculares/diagnóstico por imagem , Doenças Neuromusculares/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Hipertrofia , Perna (Membro) , Masculino , Pessoa de Meia-Idade , UltrassonografiaRESUMO
To evaluate the value of myosonography in inflammatory myopathies ultrasound of skeletal muscles was performed in 70 patients, aged 21-82 years, suffering from histologically proven polymyositis (n = 30), dermatomyositis (n = 18), granulomatous myositis (n = 9), inclusion body myositis (n = 13), and in 102 control persons. The sensitivity of muscle ultrasound in detecting histopathologically proven disease (82.9%) was not significantly different from electromyography (92.4%) or serum creatine kinase activity (68.7%). The positive predictive value of ultrasound was 95.1%, the negative predictive value 89.2%, and the accuracy 91.3%. The different types of inflammatory myopathies presented with typical, but not specific ultrasound features. Polymyositis showed atrophy and increased echointensity predominantly of lower extremity muscles, whereas in dermatomyositis clear muscle atrophy was rare and echointensities were highest in forearm muscles. Echointensities were lower in dermatomyositis compared to poly- and granulomatous myositis. Granulomatous myositis was characterized by the highest echointensities and a tendency towards muscle hypertrophy. Severe muscle atrophy was the most impressive feature in the majority of patients with inclusion body myositis. Comparison of ultrasound and histopathological findings indicates that muscle lipomatosis has a much greater impact on muscular echointensity than does muscle fibrosis. Ultrasound of myositis improved clinical assessment of patients by supplying differential diagnostic clues based on precise muscle size measurements and identification of mesenchymal abnormalities, particularly muscle lipomatosis.
Assuntos
Músculos/diagnóstico por imagem , Miosite/diagnóstico por imagem , Adulto , Idoso , Creatina Quinase/sangue , Dermatomiosite/diagnóstico por imagem , Dermatomiosite/fisiopatologia , Eletromiografia , Feminino , Humanos , Inflamação , Masculino , Pessoa de Meia-Idade , Músculos/fisiopatologia , Miosite/fisiopatologia , Miosite Ossificante/diagnóstico por imagem , Miosite Ossificante/fisiopatologia , Polimiosite/diagnóstico por imagem , Polimiosite/fisiopatologia , Valores de Referência , UltrassonografiaRESUMO
We present a case of late-onset acid maltase deficiency (AMD) with pronounced involvement of the liver and skeletal muscles. In addition, and in contrast to other adult cases of AMD, the case presented here shows CNS pathology with hypodense and hyperintense white matter areas on CT and MRI scans, and myelin changes ranging from focal areas of demyelination to necrosis. Neuropathologic changes seem to be related to unusual vascular pathology consisting of vacuolar degeneration of small and large arterial blood vessels. Vacuoles of varying size, partly filled with granular PAS-positive material, were found in pericytes and smooth muscle cells of arterial vessel walls. Electron microscopy revealed lysosomal and cytoplasmic free glycogen in smooth muscle cells in the intima of large cerebral arteries as well as in pericytes of arterioles and capillaries. Accumulation of glycogen locally was associated with severe cellular damage and necrosis. The formation of a great number of small aneurysms of intracerebral arteries is thought to be the result of cell damage in the vessel walls.
Assuntos
Artérias Cerebrais/patologia , Glucana 1,4-alfa-Glucosidase/deficiência , Aneurisma Intracraniano/etiologia , Vacúolos/ultraestrutura , Adulto , Encéfalo/patologia , Endotélio Vascular/ultraestrutura , Humanos , Aneurisma Intracraniano/patologia , Masculino , Microscopia Eletrônica , Músculos/patologiaRESUMO
Limb and trunk muscles of 57 patients with the juvenile or adult form of myotonic dystrophy were studied by imaging techniques (ultrasound, computed tomography, magnetic resonance imaging). Typical findings were atrophy of the tibialis anterior and triceps brachii muscles and fatty degeneration of the vastus intermedius, sartorius, tibialis anterior and soleus muscles as well as of medial head of the gastrocnemius muscle. Magnetic resonance imaging was the most sensitive technique in depicting mesenchymal muscle alterations, followed by computed tomography and ultrasound. The data support that imaging is more sensitive in detecting the myopathy than measurement of the creatine kinase activity.
Assuntos
Diagnóstico por Imagem , Músculos/patologia , Distrofia Miotônica/diagnóstico , Adolescente , Adulto , Idoso , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Músculos/diagnóstico por imagem , Distrofia Miotônica/diagnóstico por imagem , Distrofia Miotônica/patologia , Sensibilidade e Especificidade , Tomografia Computadorizada por Raios X , UltrassonografiaRESUMO
The temporal variation of at least two muscle fibers of the same motor unit was recorded with the single fiber EMG technique (SFEMG) by means of special needles and filter settings. In the normal musculus extensor digitorum communis (EDC) the mean variation (jitter) is not longer than 37 microseconds, the fiber density not higher than 1.7 fibers in a 10 ms window. To determine whether these parameters are affected by repeated SFEMG recordings, we measured jitter and fiber density in 20 fiber pairs in the left extensor digitorum communis muscle on day 0, 3, 6, 9 and 30 in 5 healthy volunteers. The mean jitter and the fiber density did not change significantly from day 0 (30.1 +/- 3.6 microseconds; 1.4 +/- 0.07) to day 30 (34.5 +/- 2.7 microseconds; 1.6 +/- 0.13). We conclude that repeated SFEMG recordings do not influence jitter and fiber density.
Assuntos
Eletromiografia , Músculos/fisiologia , Adulto , Humanos , Masculino , Valores de Referência , Fatores de TempoAssuntos
Encéfalo/fisiologia , Epilepsia/fisiopatologia , Magnetismo , Eletroencefalografia , HumanosRESUMO
BACKGROUND: Among radicular lesions, those affecting the T1 root are rare. Together with the similarity of symptoms to C8 syndrome, which is more common, this makes the diagnosis of T1 radiculopathy complicated. The clinical and diagnostic specifics of T1 syndrome are shown here based on three cases. MATERIALS AND RESULTS: We report on three patients with T1 syndrome. Clinical diagnostics (clinical investigation, electrophysiology, MRI) showed in two cases lateral intraforaminal disc herniae at the T1-2 level, and the third patient had metastasis of a cervix carcinoma being responsible for the radiculopathy. In all cases surgery was performed. The patients with disc herniae were immediately pain-free after surgery; in the third patient the neurological symptoms and pain clearly improved. CONCLUSIONS: These three cases show that by thorough analysis of clinical symptoms and functional (electrophysiology) and morphological (MRI) diagnostics, T1 radiculopathy can be differentiated from C8 lesions. All of the patients benefited from decompressive surgery.
Assuntos
Vértebras Cervicais/patologia , Deslocamento do Disco Intervertebral/diagnóstico , Imageamento por Ressonância Magnética , Mielografia , Síndromes de Compressão Nervosa/diagnóstico , Neoplasias da Coluna Vertebral/secundário , Raízes Nervosas Espinhais/patologia , Vértebras Torácicas/patologia , Tomografia Computadorizada por Raios X , Neoplasias do Colo do Útero/diagnóstico , Idoso , Braço/inervação , Vértebras Cervicais/cirurgia , Feminino , Dedos/inervação , Seguimentos , Humanos , Deslocamento do Disco Intervertebral/cirurgia , Laminectomia , Masculino , Pessoa de Meia-Idade , Síndromes de Compressão Nervosa/cirurgia , Exame Neurológico , Implantação de Prótese , Escápula/inervação , Neoplasias da Coluna Vertebral/diagnóstico , Neoplasias da Coluna Vertebral/cirurgia , Vértebras Torácicas/cirurgia , Neoplasias do Colo do Útero/cirurgiaRESUMO
Among the non-traumatic lesions of peripheral nerves the compression syndromes occupy a numerically leading position. After mentioning the common characteristics the individual compression syndromes of the brachial plexus and peripheral nerves of the upper extremity are described: the compression of the brachial plexus in the posterior triangle of the neck, in the costoclavicular passage and on hyperabduction. The suprascapular notch syndrome ist mentioned. The distal compression syndrome of the median nerve, the carpal tunnel syndrome is described in detail as the most common of the compression syndromes. The proximal compression syndrome of the ulnar nerve, the cubital tunnel syndrome, ist also described as are the distal compression syndrome of this nerve, Guyon's recess syndrome and the ramus profundus nervi ulnaris lesion. The supinator recess syndrome of the radial nerve is briefly mentioned.
Assuntos
Síndromes de Compressão Nervosa/patologia , Braço , Plexo Braquial/patologia , Síndrome do Túnel Carpal/patologia , Humanos , Condução Nervosa , Dor/etiologia , Nervo UlnarRESUMO
UNLABELLED: Electrodiagnostic and histometric investigations have been carried out on 56 adult male rabbits following unilateral paralysis of the recurrent laryngeal nerve. Exponential current impulses were externally applied. The excitation threshold was determined endoscopically and also described graphically in terms of the excitation intensity as a function of time (I/t-curves). The diagnostic results thus obtained permit determination of the corresponding excitation parameters for therapy. The success of the therapy was evaluated from histometric data on type I and type II fibres of the vocalis and the posterior cricoarytenoid muscles. RESULTS: 1. The stimulation of denervated laryngeal muscles by external application of exponential current impulses is selective. 2. The extent of the neurogenous atrophy of denervated muscles following paralysis of the recurrent nerve can be diagnosed electrically. 3. This atrophy could be significantly reduced by proper choice of stimulation parameters within the time span of the experiment (28 days).
Assuntos
Atrofia/etiologia , Estimulação Elétrica , Músculos Laríngeos/inervação , Músculos/inervação , Animais , Atrofia/diagnóstico , Denervação , Eletrodiagnóstico , Masculino , Paralisia/complicações , Coelhos , Nervo Laríngeo RecorrenteRESUMO
A 26-year-old male patient developed a writer's cramp syndrome, the underlying cause of which was shown to be a congenital subluxation of the first metacarpophalangeal joint. The clinical symptoms are presented, the indications for surgery reviewed and the operative technique in accordance with A.N. Witt described. Post-operatively, the pathological hypermobility of the first metacarpophalangeal joint has been eliminated, and global function of the hand has normalized.
Assuntos
Articulações dos Dedos , Luxações Articulares/congênito , Articulação Metacarpofalângica , Cãibra Muscular/etiologia , Polegar , Adulto , Escrita Manual , Humanos , Luxações Articulares/complicações , Luxações Articulares/cirurgia , Masculino , Transferência Tendinosa/métodosRESUMO
Central motor conduction times were studied using transcranial magnetic stimulation in 17 patients with syringomyelia. Central motor conduction time (lower-limb pathway) was prolonged or responses were absent in 44% of stimulations. When results were compared with clinical findings and magnetic resonance tomography, only a weak correlation was found. Transcranial magnetic stimulation is thus of limited value for diagnosing and monitoring the course of syringomyelia.
Assuntos
Neurônios Motores/fisiologia , Condução Nervosa/fisiologia , Estimulação Física/métodos , Siringomielia/fisiopatologia , Potenciais de Ação/fisiologia , Adulto , Idoso , Córtex Cerebral , Feminino , Humanos , Magnetismo , Masculino , Pessoa de Meia-IdadeRESUMO
The central motor conduction time (CMCT) was measured by electrical transcranial and spinal stimulation in 70 consecutively admitted patients with definite multiple sclerosis and 26 normal volunteers. The results of the patientgroup were compared with visual and somatosensory (median and tibial nerve) evoked potentials. The mean CMCT of the volunteers was 5.4 ms versus 11.1 ms in the patient group. In 55 of the 70 patients (79%) the CMCT was delayed (p less than 0.0001). VEP showed pathologic results in 67%, SEP of tibial nerve in 51%, SEP of median nerve in 41% of the patients. In 10 of the 70 cases (15%) only CMCT was pathologic. Especially in the first attack of the disease the CMCT (79% pathologic results) was superior in comparison to the evoked potentials (VEP and SEP together 43% pathologic findings). In our cases without clinical evidence of a pyramidal tract lesion a subclinical affection of this pathway could be determined in 69% by a pathologic CMCT. We regard this method therefore as a valuable tool in the early diagnosis of multiple sclerosis.
Assuntos
Potenciais Somatossensoriais Evocados , Potenciais Evocados Visuais , Córtex Motor/fisiopatologia , Esclerose Múltipla/fisiopatologia , Transmissão Sináptica , Adulto , Diagnóstico Diferencial , Dominância Cerebral/fisiopatologia , Estimulação Elétrica , Feminino , Humanos , Masculino , Nervo Mediano/fisiopatologia , Pessoa de Meia-Idade , Esclerose Múltipla/diagnóstico , Músculos/inervação , Tratos Piramidais/fisiopatologia , Nervo Tibial/fisiopatologiaRESUMO
A 35-year-old man, previously healthy except for a grade 1 goitre, sustained a spontaneous left pneumothorax treated with a Bülau drain. When the left pneumothorax recurred 2 months later a left thoracotomy was performed. Two bullae at the lung apex were resected and a pleurodesis performed. After the operation the patient noted hypaesthesia of the dorsum of the left upper arm, mild ptosis of the left eyelid as well as reduced sweat secretion over the left half of the face and the left rib cage. The hypaesthesia improved, but the sympathetic nerve deficits remained. There were no other neurological signs. 9 months later, within one minute of eating a sour apple, the patient developed severe sweating over the left half of the face and the left chest. The reaction was confirmed by infra-red thermography which proved that the skin temperature in the sweating region had fallen to 3 degrees C. The likely cause of localized gustatory sweating is intra-operative damage of the stellate ganglion or its preganglionic nerve connections. Treatment is limited to avoidance of the precipitating gustatory stimulus.