[Neurologic diagnostics in general practice].
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Cornea↗
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Results for “REFLEX, ABNORMAL”
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[Hyperekplexia -- a treatable neuropediatric disease].
Hyperekplexia (OMIM 138491) is primarily an autosomal dominant disease characterized by exaggerated startle reflex and neonatal hypertonia. If untreated it can be associated with sudden infant death from apnea or aspiration pneumonia and serious injuries. Different mutations of the alpha1-subunit of inhbitory glyzine receptor (GLRA1) could be found. Clonazepame, a gammaaminobutyric acid (GABA) receptor agonist is the therapy of choice. An early diagnose will lead to appropriate treatment and genetic counseling.
Amino Acid Sequence↗
[Combination big-toe stretch reflex for the detection of latent pyramidal signs].
The stretch-reflex of the extensor hallucis muscle will only become apparent when in case of an upper motor neuron lesion the extensor hallucis response is stimulated simultaneously. This extrinsic-intrinsic combinative reflex may be useful to elicit a latent extensor response or to prove a doubtful one.
Humans↗
Elevation of cerebrospinal fluid substance P concentrations in spina bifida.
Concentrations of substance P, a peptide believed to have neurotransmitter and possible trophic functions, were determined by radioimmune assay in the cerebrospinal fluids of ten babies and one foetus with spina bifida, and compared to those of five normal babies and ten normal foetuses. The results (mean +/- S.E.M.) were: spina bifida babies (864 +/- 357.6 fmol ml-1), normal babies (141 +/- 14.2 fmol ml-1), spina bifida foetuses (150,000 fmol ml-1), normal foetuses (22,673 +/- 8,340 fmol ml-1). Hence, in spina bifida cerebrospinal fluid substance P concentrations were grossly elevated both pre- and post-natally. The significance of these results can be considered from two aspects: there is the possibility that substance P plays a role in the development of the spinal cord which is disturbed in spina bifida; as substance P has been shown to be involved with sensory perception and autonomic reflexes, abnormal concentration of substance P in cerebrospinal fluid may aggravate the neurological deficit in spina bifida. Possibly, therapeutic manipulation of substance P, when available in the future, may be considered in these patients.
Female↗
Role of cholinergic mossy fibers in vestibular nuclei in the development of vestibular compensation.
Several lines of evidence have suggested that acetylcholine is a possible neurotransmitter/neuromodulator involved in vestibular compensation. However, details of cholinergic effective sites during vestibular compensation remain unclear. In this study, we selectively damaged the rat vestibulo-floccular cholinergic mossy fibers using ethylcholine mustard aziridinium ion. In these animals, unilateral labyrinthectomy caused more severe vestibulo-ocular deficits, especially in the initial stage. These findings suggest that the vestibulo-floccular cholinergic mossy fibers serve to restore the balance between intervestibular nuclear activities in order to induce vestibular compensation in the initial stage.
Animals↗
The vertical linear vestibulo-ocular reflex in patients with a hyperactive response during horizontal angular acceleration.
OBJECTIVE: In clinical routine, some patients show a bilateral hyperactive response of the angular vestibulo-ocular reflex (AVOR). The aim of this prospective study was to determine whether these patients also show hyperactivity of the linear VOR (LVOR). MATERIAL AND METHODS: In 10 patients with a hyperactive AVOR (total amplitude of post-rotatory nystagmus > 400 degrees per 30 s) and 10 healthy subjects the AVOR (stopped after 180 s of rotation at 90 degrees/s) and vertical LVOR (amplitude 5 cm, frequency 1.2 Hz) were tested with eyes open in the dark. During vertical linear acceleration, each subject was instructed to look at an earth-fixed target and they performed vertical smooth pursuit as stationary observers. RESULTS: The mean eye velocity of the AVOR was significantly higher in the patients than the healthy subjects (19 vs 5 degrees/s; p = 0.00016). During vertical linear acceleration in darkness (49 vs 23 degrees/s; p = 0.004) and combined maculo-visual stimulation (88 vs 52 degrees/s; p = 0.007) the patients showed a significantly higher mean vertical eye velocity. When vertical smooth pursuit was performed, no significant differences were registered. All 20 subjects showed a significant (p = 0.01) positive Spearmnan correlation (rs = 0.79) between the eye velocities of AVOR and LVOR. CONCLUSION: Patients with a hyperactive AVOR also showed hyperactivity of the LVOR. Because two different sensory end organs and neuronal pathways are involved in these responses, a central rather than a peripheral vestibular lesion must be held responsible.
Acceleration↗
Neurologic assessment in the first year of life.
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Child Development↗
Frontal lobe trauma in the elderly. Personality changes aren't always dementia.
Changes in personality and behavior are fairly specific when they are caused by damage to the frontal lobe of the cerebral cortex. They are characterized by changes in affect and in emotional response and may be pseudopsychopathic, pseudodepressive, or a combination of both. Cognitive ability (eg, verbal fluency, maintaining attention, achieving goals) may also be diminished. Neurologic signs may include abnormal reflexes, increased or decreased motor behavior, and loss of ability to complete purposeful movement. If the damage is caused by trauma, treatment begins with care of the acute injury. Any resulting seizures should be treated with an anticonvulsant and the patient observed carefully for side effects. Another agent (eg, a stimulant, antipsychotic, tricyclic antidepressant) may be needed as well, depending on the individual patient, to restore as much psychological function as possible. Counseling of both the patient and the family is important to help them avoid some difficulties and frustrations that may accompany the change in personality.
Aged↗
Critical review of passive muscle stretch: implications for the treatment of children in vegetative and minimally conscious states.
The efficacy of passive muscle stretch in the treatment of children in vegetative (VS) and minimally conscious (MCS) states is reviewed. Seventeen studies are critically reviewed. Study quality was evaluated using a quality filter adapted from Guyatt. Levels of evidence were assigned to each study using criteria based on Sackett's guidelines and a recent adaptation of those guidelines. Based on these levels of evidence, specific recommendations were made. These recommendations were classified as grade A, B, C or D depending on the levels of evidence used to generate them. There is limited evidence to support the efficacy of passive muscle stretch to improve range of motion and reduce spasticity in children in VS and MCS. Caution must be used when interpreting these recommendations because of the limited number of studies available and the extrapolation of study results from a different population. Further research is needed to strengthen these recommendations and establish the efficacy of passive muscle stretch in the treatment of children in VS and MCS.
Child↗
Hyperekplexia: a rare differential of neonatal fits described in a developing country.
Hyperekplexia is a rare condition in which there is an exaggerated startle response. We report how a case presented in Papua New Guinea (PNG) and was diagnosed with international support. This is the first reported case in PNG. It is an important diagnosis to make to prevent sudden death and inappropriate treatment. The case illustrates the benefit of having a link with an international specialist and we discuss the importance of communication between developing and industrialized countries.
Anticonvulsants↗
Neurophysiological methods for the assessment of spasticity: the Hoffmann reflex, the tendon reflex, and the stretch reflex.
PURPOSE: To review the literature concerning neurophysiological methods to assess spasticity with respect to mechanisms and methodology, and to describe the three most commonly used methods: the Hoffmann reflex (H-reflex), the Tendon reflex (T-reflex), and the Stretch Reflex (SR). METHOD: A systematic internet database search was performed to identify neurophysiological measurement methods of spasticity. A systematic exclusion procedure resulted in 185 included references, completed by additional informal search. For this paper, information about the H-, T- and stretch reflexes was extracted from these references. RESULTS: Although the reflexes are basically monosynaptic, there are many supraspinal pathways which modulate the responses in terms of their amplitude and latency. As a consequence the methods are sensitive to a considerable number of experimental conditions and are characterized by a moderate reliability and sensitivity. Correlations with other (i.e. biomechanical, neurophysiological or clinical) spasticity assessment parameters are moderate to poor. Standardised and broadly accepted protocols are still largely lacking preventing an effective exchange of knowledge. CONCLUSIONS: The clinical and experimental use of the three methods is restricted due to moderate reliability and sensitivity. It is recommended to perform combined neurophysiological-biomechanical assessment of spasticity during active, functional movement.
Electromyography↗
Relation between spasticity, weakness and contracture of the elbow flexors and upper limb activity after stroke: an observational study.
PURPOSE: Understanding the relationship between the motor impairments and their impact on physical activity will allow rehabilitation after stroke to be based on scientific principles. The aims of this study were to determine: (i) the relative contribution of weakness and spasticity to contracture, and (ii) the relative contribution of all three impairments to limitations in physical activity during the first 12 months after stroke. METHOD: This longitudinal observational study charted the evolution of weakness (loss of maximal force), spasticity (stretch-evoked EMG) and contracture (loss of joint range) of the elbow flexors and limitations in upper limb activity (Motor Assessment Scale) for a year after stroke in 27 subjects who had suffered a first stroke. Spasticity was measured as abnormal reflex activity, weakness was measured as loss of maximum isometric torque, contracture was measured as the difference in range of motion between the affected and intact side, and limitations in physical activity were measured on a clinical scale. RESULTS: The major independent contributors to contracture were spasticity for the first four months after stroke (p = 0.0001 - 0.10) and weakness thereafter (p = 0.01 - 0.05). However, the major and only independent contributor to limitations in physical activity throughout the year was weakness (p = 0.0001 - 0.05). CONCLUSIONS: For the first time, from a longitudinal study, the findings show that spasticity can cause contracture after stroke, consistent with the prevailing clinical view. However, weakness is the main contributor to activity limitations.
Adult↗
Deep tendon reflexes: a study of quantitative methods.
OBJECTIVE: The deep tendon reflex (DTR) is routinely used by clinicians to evaluate the nervous system. Depressed and hyperactive DTRs suggest peripheral and central nervous system compromise, respectively. Limitations of DTRs are: qualitative nature of the assessments based upon subjective grading, and limited inter-rater reliability. This preliminary study was undertaken to quantify the tendon tap used by clinicians to elicit DTRs and the reflex response elicited. METHODS: Tendon taps were applied to a force transducer in hypo-, normo-, and hyperreflexic ranges by 2 clinicians, using 3 different tendon hammers (Babinski, Queen Square, and Taylor). Patellar DTRs, measured as joint angle excursion with an electrogoniometer, were compared in hyper- and normoreflexic individuals. RESULTS: Median peak tap force was 1 2.8, 38.0, and 85.2 Newtons (Nt), respectively, for eliciting hyper-, normo-, and hyporeflexic DTRs. Peak tap force was similar in the hyper- and normoreflexic ranges for all 3 hammers; in the hyporeflexic range, peak tap forces with the Taylor hammer were lower. A good distinguishing feature between hyper- and normoreflexic patellar DTRs was briskness, measured as the quotient of knee excursion divided by peak tendon tap force. Knee excursion is a non-linear patellar DTR response, when measured sitting. CONCLUSIONS: Peak tap forces used by clinicians fall into 3 ranges: 0-20 Nt for hyperreflexia, 21-50 Nt for normoreflexia, and >50 Nt for hyporeflexia. The Taylor hammer, with small mass and short handle, has a ceiling effect in the hyporeflexic range. We propose a systematic method for DTR testing.
Central Nervous System Diseases↗
Role of positive anorectal feedback in rectal evacuation: the concept of a second defecation reflex: the anorectal reflex.
BACKGROUND/OBJECTIVE: The present study investigated the hypothesis that rectal contraction is maintained by positive anorectal feedback elicited by continuous passage of stools through the rectal neck (anal canal), and that cessation of stool passage aborts rectal contraction. METHODS: Anal and rectal pressures were measured in 18 healthy volunteers (mean age = 38.6 years; 10 men, 8 women) during evacuation of saline infused into the rectum. Residual fluid volume was calculated. The test was repeated after separate application of lidocaine or bland gel to the rectal neck. RESULTS: On evacuation, fluid emanated from the rectal neck in continuous flow with no, or mild, straining. No residual saline was collected from 16 of 18 participants. After anal anesthetization, evacuation occurred in gushes induced with excessive straining; residual fluid was huge. Repetition of the test 2 hours after anesthetization produced the same results as before anesthetization. Bland gel applied to the rectal neck yielded results similar to those before gel application. CONCLUSION: Rectal contraction at defecation is suggested to be maintained by positive anorectal feedback evoked by continuous passage of stool through the rectal neck. This feedback appears to be affected through an anorectal excitatory reflex (ARR), which produces rectal contraction upon stimulation of anal stretch receptors. Abortion of this reflex by anal anesthetization seems to result in failure of the rectum to contract and in excessive straining to achieve rectal evacuation. ARR thus is suggested to be a second defecation reflex necessary to continue defecation, whereas the rectoanal inhibitory reflex is the primary reflex. The role of the ARR in pathogenesis of constipation and its utility in spinal cord injury need to be investigated.
Adult↗
Quantification of hyperreflexia in amyotrophic lateral sclerosis (ALS) by the soleus stretch reflex.
UNLABELLED: The aim of this study was to quantify upper motor neuron (UMN) involvement in amyotrophic lateral sclerosis (ALS) by the soleus stretch reflex. METHODS: In a group of 24 ALS patients and ten healthy controls the soleus stretch reflex was elicited by a four degree rotation at the ankle joint. Amplitude of the short-latency stretch reflex, threshold, and sensitivity were determined. Peripheral excitation/contraction properties were evaluated by supramaximal stimulation of the tibial nerve. Clinical scores of upper motor neuron involvement were applied. RESULTS: A highly significant correlation between threshold and sensitivity of the stretch reflex and clinical score of upper motor neuron involvement was found; patients with a low threshold and a high sensitivity in general had a high upper motor neuron score. CONCLUSION: It is suggested that upper motor neuron involvement in ALS can be evaluated by using the soleus stretch reflex. This may be useful in monitoring progression of the disease and evaluating new therapies.
Adult↗
Re-examination of the possible role of Golgi tendon organ and muscle spindle reflexes in proprioceptive neuromuscular facilitation muscle stretching.
Literature concerning the theoretical role of spinal reflex circuits and their sensorimotor signals in proprioceptive neuromuscular facilitation (PNF) muscle stretching techniques was examined. Reviewed data do not support the assertion commonly made in PNF literature that contraction of a stretched muscle prior to further stretch, or contraction of opposing muscles during muscle stretch, produces relaxation of the stretched muscle. Further, following contraction of a stretched muscle, inhibition of the stretch reflex response lasts only 1 s. Studies examined suggested that decreases in the response amplitude of the Hoffmann and muscle stretch reflexes following a contraction of a stretched muscle are not due to the activation of Golgi tendon organs, as commonly purported, but instead may be due to presynaptic inhibition of the muscle spindle sensory signal. The current view on the complex manner by which the spinal cord processes proprioceptive signals was discussed. The ability of acute PNF stretching procedures to often produce a joint range of motion greater than that observed with static stretching must be explained by mechanisms other than the spinal processing of proprioceptive information. Studies reviewed indicate that changes in the ability to tolerate stretch and/or the viscoelastic properties of the stretched muscle, induced by PNF procedures, are possible mechanisms.
Elasticity↗
Alteration in rate modulation of reflexes to lumbar motoneurons after midthoracic spinal cord injury in the rat. I. Contusion injury.
This study investigated the regulation of reflex excitability in normal and midthoracic contusion-injured animals. Recent observations revealed that rate depression, a rate-modulatory process that decreases reflex excitability, was significantly decreased following experimental midthoracic contusion injury. The present experiments were performed to extend those studies and to determine if posttetanic potentiation (PTP), a rate-modulatory process that increases reflex excitability, also was altered in lumbar monosynaptic reflexes (MSRs) following midthoracic contusion injury. In normal animals, a mean PTP of 160% of the pretetanus control was observed at 30 sec following tetanus of the tibial MSR. The decay of the PTP in normal animals followed a rapid initial, then a more gradual pattern, before returning to pretetanus values by 5 min posttetanus. Following midthoracic contusion injury, the maximal (unpotentiated) MSRs were significantly increased in amplitude, whereas the percent potentiation of the PTP of the tibial MSRs was significantly decreased. PTP decay in postcontusion animals was significantly more gradual than observed in normal animals and followed a single decay process. Further analysis of rate depression of tibial MSRs in normal animals revealed that the attenuation pattern produced by stimulation within the lower range of test frequencies was different from that produced by stimulation at the higher test frequencies. Following contusion, rate depression of tibial MSRs was significantly reduced at all test frequencies. These physiological changes in the stretch reflex neural pathway are discussed relative to the development of spasticity.
Animals↗
Audiogenic startle reflex of man and its relationship to startle syndromes. A review.
The normal human audiogenic startle reflex is defined from a review of the literature, substantiated by a current investigation of normal subjects, and clarified pathophysiologically by a discussion of animal experimentation. The basic information is used to evaluate critically a variety of syndromes loosely termed 'startle' in the past. A new classification of startle syndromes is proposed.
Adult↗