Habituación del reflejo acústico-palpebral en la enfermedad de Parkinson / Habituation of the acoustic-blink reflex in Parkinson's disease

La oclusión palpebral ante un estímulo auditivo sorpresivo es una respuesta refleja [RAP] polisináptica de integración mesencefálica que tiende a desaparecer frente a estímulos repetidos. Este reflejo transcurre a través del núcleo coclear, cuerpo trapezoide, collículo inferior y sus conexiones, y está sujeto a influencias supramesencefálicas. En el estudio presente, se evaluaron electrofisiológicamente 6 individuos normales y 6 pacientes con enfermedad de Parkinson de edades similares. Se aplicaron estímulos tonales registrándose la actividad refleja en el orbicular de los párpados. Se midieron latencia [L], duración [D], amplitud [A] y fases [F] de las respuestas reflejas obtenidas por aplicación de estímulos auditivos a intervalos randomizados, y luego de un período de reposo, se midió el número de respuestas obtenidas [R] aplicando los estímulos a una frecuencia fija de 0,2 Hz. No se observaron diferencias significativas en L,D,A y F, viéndose en cambio, un mayor número de R en los enfermos de Parkinson. Esta observación sugiere una alteración en la habituación a los estímulos auditivos posiblemente debida a fallas en la inhibición de este reflejo por compromiso de estructuras supramesencefálicas

Habituación del reflejo acústico-palpebral en la enfermedad de Parkinson / Habituation of the acoustic-blink reflex in Parkinsons disease

La oclusión palpebral ante un estímulo auditivo sorpresivo es una respuesta refleja [RAP] polisináptica de integración mesencefálica que tiende a desaparecer frente a estímulos repetidos. Este reflejo transcurre a través del núcleo coclear, cuerpo trapezoide, collículo inferior y sus conexiones, y está sujeto a influencias supramesencefálicas. En el estudio presente, se evaluaron electrofisiológicamente 6 individuos normales y 6 pacientes con enfermedad de Parkinson de edades similares. Se aplicaron estímulos tonales registrándose la actividad refleja en el orbicular de los párpados. Se midieron latencia [L], duración [D], amplitud [A] y fases [F] de las respuestas reflejas obtenidas por aplicación de estímulos auditivos a intervalos randomizados, y luego de un período de reposo, se midió el número de respuestas obtenidas [R] aplicando los estímulos a una frecuencia fija de 0,2 Hz. No se observaron diferencias significativas en L,D,A y F, viéndose en cambio, un mayor número de R en los enfermos de Parkinson. Esta observación sugiere una alteración en la habituación a los estímulos auditivos posiblemente debida a fallas en la inhibición de este reflejo por compromiso de estructuras supramesencefálicas

Reflex and dilatation: a clinical epidemiological evaluation.

The recent controversy surrounding the use of the reflex anal dilatation (RAD) sign in cases of suspected sexual abuse is a general illustration of the difficulties clinicians face in determining which symptoms, signs or laboratory tests to use in their daily practice. The evidence required fully to evaluate RAD is incomplete. The specificity in particular is uncertain. Sufficient evidence is, however, available to permit a quantitative examination of the test's performance under various circumstances. Our analysis suggests that, at the prevalence of anal abuse reported in one large series of children referred to paediatricians with suspected sexual abuse (13%), only if the specificity of the test is 99% or greater, may the positive predictive value of RAD be as high as 90%. At the likely prevalence of anal abuse in the general child population (less than 0.5%), however, an even higher specificity of 99.99% would be necessary to achieve a similar positive predictive value.

Abnormalities of the blink reflex in Gilles de la Tourette syndrome.

The blink reflex and it's recovery cycle were studied in 26 patients with Gilles de la Tourette syndrome and 10 controls. There was a significant increase in the mean duration of the R2 response. The amplitude of the R2 response following paired shocks (mean R2[T]/R2[C]%) was 11%, 40% and 52% of the conditioning stimulus with intervals of 200 ms, 500 ms and 1 second in the patients, compared with 10%, 17% and 32% respectively in the controls. Half the patients, however, had normal recovery cycles and voluntary suppression of tics and blinks reduced the amplitude of R2 in all patients. These results suggest increased excitability of brainstem interneurons in Gilles de la Tourette syndrome.

Diphtheritic neuropathy, an analysis based on muscle and nerve biopsy and repeated neurophysiological and autonomic function tests.

A patient with diphtheritic neuropathy was investigated with repeated tests of parasympathetic and sympathetic vasomotor and sudomotor functions for one year after the onset of symptoms. Somatic nerve function was tested with nerve conduction studies and an index based on ten variables was used to follow the course of the neuropathy. Sural nerve and anterior tibial muscle biopsies were performed. A severe but shortlasting impairment of the parasympathetic vagal reflex arc was found. The recovery of this function paralleled the clinical course. Sympathetic functions were normal. The neurophysiological variables of somatic nerve function showed signs of a mainly demyelinating mixed sensory/motor neuropathy. The recovery of these variables was slow. The nerve and muscle biopsies demonstrated mild changes consistent with a mixed, demyelinating, non-inflammatory neuropathy.

[The endonasopalpebral reflex]. / Ob éndonazopal'pebral'nom reflekse.

The authors describe the endonasopalpebral reflex which is evoked from the nasal mucosa. Reduction of this reflex may be used as a fine index of involvement of the trigeminus in patients with acoustic neuromas. This makes it possible to differentiate this tumour at early stages of its development from neuritis of the acoustic nerve. This is of great importance for this pathological situation.

Hand muscle reflexes following electrical stimulation in choreatic movement disorders.

Thenar reflexes following electrical stimulation of the median nerve (containing proprioceptive and cutaneous afferents) and the radial superficial nerve (cutaneous afferents only) were investigated in 23 patients with manifest Huntington's disease (HD) at an early stage, in 17 clinically healthy descendants of HD-patients and in 18 patients with choreatic hyperkinesia due to various aetiologies other than HD. In 61% of the patients with early HD the long-latency reflexes (LLR) were uni- or bilaterally absent in response to both median nerve and radial superficial nerve stimulation. The remaining patients had a diminished mean amplitude and mean duration of their LLR. In contrast, offspring and patients with symptomatic chorea had preserved LLR which did not differ in amplitude or duration from normal controls. Additionally, the mean amplitude and mean duration of the Hoffmaan-reflex (HR) was found to be increased in patients with HD and their offspring but not in patients with other aetiologies. It is concluded (1) that the loss of LLR is not related to the choreatic hyperkinesia itself but to the degeneration of a hitherto poorly defined neuronal circuit in HD; (2) that among a variety of diseases presenting with chorea, the loss of LLR seems to be specific for HD; (3) that the testing of hand muscle reflexes in choreatic movement disorders is helpful for the differential diagnosis of early HD but not for the detection of gene carriers among offspring of patients with HD.

Anorectal abnormalities in progressive systemic sclerosis.

Seventeen patients with progressive systemic sclerosis (PSS) were evaluated with manometry for anorectal function, and an additional 36 age-matched normal subjects were collected as a control group. The study group had a significant decrement of maximum basal pressure (MBP), 42.6 +/- 27.0 mm Hg, in PSS as compared with the control group, 71.2 +/- 24.9 mm Hg (P = .0004). The difference in the functional length (FL) of the anal canal, PSS:control = 2.4 +/- 1.0 cm:3.7 +/- 0.5 cm (P = .0001); the volume of first defecating sensation, PSS:control = 66.3 +/- 35.2 ml:125.1 +/- 43.8 ml; the voluntary component, the difference between maximum squeeze pressure (MSP) and MBP, PSS:control = 116.6 +/- 73.6 mm Hg:61.8 +/- 35.9 mm Hg (P = .0087), were also found to be statistically significant. Nevertheless, the MSP and maximal tolerable capacity (Vmax) showed no difference in these two groups (MSP, PSS:control = 159.3 +/- 88.1 mm Hg:132.9 +/- 44.9 mm Hg, P = .259), (Vmax, PSS:control = 193.1 +/- 67.7 ml:230.0 +/- 60.9 ml, P = .0526). Twelve (71 percent) of 17 patients did not have rectoanal inhibitory reflex, and paradoxical contraction during rectal balloon inflation was noted in ten patients. Nine patients had different degrees of anal incontinence and abnormal anometric profiles were found in six of eight asymptomatic patients. Therefore, only two patients (12 percent) had neither symptoms nor anometric evidence of anorectal involvement in PSS. Two patients with long-standing disease received posterior anal repair for stool incontinence, the postoperative results were satisfactory both subjectively and objectively. The average MBP increased from 0 to 20 mm Hg, average FL from 0 to 1.5 cm. Patients complained less frequently about stool incontinence or soiling, and their daily life is now more comfortable. The analysis indicates that anorectal function in PSS is affected much more frequently and earlier than thought. Anorectal manometry can be used as an adjuvant in diagnosing controversial cases. Once anal incontinence occurs, posterior anal repair can achieve good results after six months of follow-up.

Reflex inhibition of thigh muscles in knee injury. Causes and treatment.

There are several common findings and contradictions noted in the research related to thigh muscle reflex inhibition and sequelae that occur with knee joint injury. Reflex inhibition may be measured directly by electromyography, or the sequelae of reflex inhibition may be measured, as commonly occurs in the clinic setting. Electromyography is useful in determining the causes of reflex inhibition. The most frequently cited causes of thigh muscle reflex inhibition in knee injury are pain, joint effusion and knee immobilisation. The other measurement methods described vary from thigh circumference measurement to muscle biopsy. These methods are useful in determining the magnitude and duration of the deleterious sequelae that affect the thigh muscles after reflex inhibition. Finally, there is selectivity of reflex inhibition after knee joint injury: the quadriceps versus the hamstrings, the different components of the quadriceps muscle group, and the different types of muscle fibres. In light of these findings, several suggestions have been offered for prevention of reflex inhibition and for techniques that can be applied to rehabilitate the most affected muscle group: the quadriceps femoris. Techniques used to prevent or limit the amount of reflex inhibition include cryotherapy, transcutaneous electrical nerve stimulation, iontophoresis, phonophoresis, joint mobilisation, rest and proper positioning of the knee in rest and exercise. Electromyostimulation, electromyographic biofeedback and traditional exercise training are 3 methods used to rehabilitate the quadriceps.

Multi-beat clonus in a patient without an upper motor neuron lesion. A case report.

The authors present a case of five-beat clonus in the absence of a central nervous system pathologic condition. As data obtained from the literature demonstrate, clinicians should be aware that multi-beat clonus is not always associated with upper motor neuron lesions.

Whole body autoregulation in conscious areflexic rats during hypoxia and hyperoxia.

We have previously shown whole body autoregulation during normoxia in conscious areflexic rats in response to an acute increase and decrease in blood volume. In this study we used this technique to determine the effect of hypoxia and hyperoxia on whole body autoregulation. Rats with an arterial catheter for blood pressure measurement and an electromagnetic flow probe for cardiac output measurement were placed in a chamber with a controlled oxygen environment. Neurohumoral blockade was achieved with chlorisondamine (10 mg/kg), methscopolamine (0.5 mg/kg), captopril (1 mg/kg), and [d(CH2)5Tyr(Me)]arginine vasopressin (10 micrograms/kg). Hemodynamic variables were restored to normal with a constant norepinephrine infusion. Group 1 (n = 7) underwent a 6-min infusion of donor blood (0.9 ml) during hypoxia (Po2 = 52 +/- 3 mmHg) and hyperoxia (Po2 = 296 +/- 12 mmHg). Group 2 (n = 8) was subjected to a 6-min withdrawal of blood (0.9 ml) during hypoxia (72 +/- 2 mmHg) and hyperoxia Po2 = 258 +/- 8 mmHg). The slope of the pressure-flow relationship was used as an index of autoregulation so that a slope of 0 indicated complete autoregulation and a slope of 1 represented no autoregulation. The pressure-flow slopes with volume expansion were 0.54 during hypoxia and 0.15 during hyperoxia, while the slopes with volume contraction were 0.29 during hypoxia and 0.54 during hyperoxia. Thus, when arterial pressure was raised above normal, the autoregulatory capacity was greater during hyperoxia than with hypoxia. Conversely, when arterial pressure was lowered below normal, the autoregulatory capacity was greater during hypoxia than with hyperoxia.(ABSTRACT TRUNCATED AT 250 WORDS)

Behavioral characteristics and early temperament of premature infants with intracranial hemorrhage.

Behavioral characteristics of 12 full-term and 44 premature infants with and without intracranial hemorrhage (ICH) were studied. Cranial ultrasonography prospectively documented Grade I-II ICH in 14, Grade III-IV in 19 and no ICH in 11 premature infants. Examination at corrected age of 40 +/- 2 weeks using the Neonatal Behavioral Assessment Scale showed that infants in the ICH groups had lower levels of arousal and more abnormal reflexes than full-terms. Infants with ICH III-IV displayed less optimal motor responses than full-term infants and diminished orientation responses, especially to visual stimuli. Thus, lower level of arousal, immature motoric processes, and poor visual orientation differentiated premature with ICH from full-term infants, although premature infants without these sequelae, did not differ significantly from full-term infants. The above may represent early manifestations of visual-perceptual and motor problems noted in the follow-up of ICH infants. Further, neonatal behavior was found to affect parent ratings of infant temperament (via the Bates Infant Characteristics Questionnaire) at 3 months corrected age, and the relationships between neonatal behavior and parental ratings differed depending upon the infant's gestational age and severity of hemorrhage. We conclude that neonatal behaviors are less optimal in premature infants, and least optimal in premature infants with severe intracranial hemorrhage when compared to fullterm infants.

Hypoxic-ischemic spinal cord injury following perinatal asphyxia.

The role of spinal cord injury in the pathogenesis of abnormal motor signs (depressed tone and reflexes) following severe perinatal hypoxia-ischemia was prospectively evaluated by clinical, electrophysiological, and neuropathological examinations in 18 asphyxiated neonates. All infants had an abnormal mental status (lethargy or coma), and seizures were present in 12. Neuromuscular examinations revealed hypotonia or flaccidity and hyporeflexia or areflexia in all infants. Neuropathological examinations of the cerebrum and spinal cord were conducted in the 12 neonates who expired. Cerebral pathological findings included cortical neuronal necrosis in 10 of 12 and subcortical white matter injury in 5 of 12. All infants with coma or seizures displayed diffuse cortical injury, but no injury conformed to a parasagittal "watershed" distribution. Spinal cord gray matter displayed prominent ischemic necrosis in 5 patients who were typically flaccid and areflexic. Electromyographic examinations of all 6 survivors were abnormal, consistent with recent injury to the lower motor neuron above the level of the dorsal root ganglion. We conclude that ischemic injury to anterior horn cells within spinal cord gray matter is relatively common among hypotonic-hyporeflexic neonates following severe perinatal hypoxia-ischemia. Although the acute neurological syndrome of neonatal asphyxia is often overshadowed by prominent cerebral signs such as coma and seizures, the motor abnormalities may be partially attributed to concurrent spinal cord injury.

Effect of cerebellectomy on reflex micturition in the decerebrate dog as determined by urodynamic evaluation.

The effect of cerebellectomy on reflex micturition in the decerebrate dog was investigated by cystometric and striated urethral sphincter EMG studies. Before and after cerebellectomy, reflex micturition consisting of bladder contraction and spasmodic contraction of the striated urethral sphincter occurred when a critical degree of filling was reached. Cerebellectomy showed no influence on the striated urethral sphincter EMG activity. However, cerebellectomy produced a significant decrease in threshold volume and threshold pressure during the collecting phase, and also in the contraction pressure and voided volume of the emptying phase. The present study suggests that the cerebellum plays an inhibitory role in the collecting phase and a facilitatory role in the emptying phase during the entire reflex micturition cycle of the decerebrate dog. Further study will have to be done concerning the neurotransmission mechanism that causes these different effects in the collecting and emptying phases.

[Unusual pyramidal pathology syndrome]. / O svoeobraznom sindrome piramidnoi patologii.

A syndrome is described comprising: 1, impossibility to close only one eye (right or left) at a time, or each eye alternatively with intact capability of closing both eyes; 2, unvoluntary screwing up of an eye during voluntary closing of another (palpebro-palpebral synkinesia); 3, head turning to the side of an eye closed (palpebrocervical synkinesia); 4, with the hands clenched, left thumb is over the right, as is the left arm over the right when folded. The syndrome is supposed to be related with consealed lefthandedness which is presumably indicative of lateralization of the dominant speech center. If this is correct, the syndrome may have a distinct topical diagnostic value.