Journal of the neurological sciences
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Comparative Study Clinical Trial
Home mechanical ventilation for amyotrophic lateral sclerosis: nasal compared to tracheostomy-intermittent positive pressure ventilation.
People with amyotrophic lateral sclerosis (ALS) usually die from respiratory failure unless they use mechanical ventilation (MV). Many die of respiratory failure without being adequately informed about the available options, such as MV that can provide symptomatic relief and prolong survival. The traditional method of MV used for persons with ALS has been tracheostomy-intermittent positive pressure ventilation (IPPV). ⋯ In conclusion, home mechanical ventilation with nasal or tracheostomy-IPPV are options for selected people with ALS. Nasal-IPPV offers may advantages; it was only used when MV was planned and desired. Nasal-IPPV can be used unless bulbar impairment is severe.
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For the bulbar ALS/MND patient with dysphagia, the accumulation of oral secretions is a distressing problem. The control of these secretions, particularly the thick mucus form, is very difficult. In approaching this problem it is important to realise that the source of these secretions is not just from the oral salivary glands. ⋯ Stimulation of cholinergic receptors produces thin serous secretions whereas beta adrenergic receptors produce thick protein and mucus-rich secretions. Therefore 16 bulbar ALS/MND patients were treated with beta antagonists after maximising other therapy. 75% of this group had fast and significant relief from their thick secretions. It is therefore proposed to perform a large controlled trial of beta blockers in the control of thick oral secretions in ALS/MND based on these promising pilot data.
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Following magnetic transcranial stimulation, motor-evoked potentials (MEPs) from the abductor digiti minimi muscle, and evoked spinal cord potentials (ESCPs) from the cervical epidural space were recorded simultaneously in 9 subjects in the awake and anesthetized condition. In the awake condition, during voluntary contraction, one (n = 5) or two (n = 4) components of the ESCPs were elicited at the threshold stimulus intensity of the MEPs. As the stimulus intensity increased, an early response (n = 7) and multiple late components were recorded. ⋯ These results suggest that transcranial magnetic stimulation generates I-waves preferentially when the stimulus intensity was set at just the threshold level of the MEPs during voluntary contraction in the awake condition. At high stimulus intensity, transcranial magnetic stimulation can elicit both D- and I-waves, but most spinal cells require I-wave activation to fire. Facilitatory effects of voluntary contraction on the muscle response following transcranial magnetic stimulation mainly originates at a spinal level.
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Autonomic dysfunction is a common complication of peripheral neuropathies. It is often of little clinical importance, but some conditions may cause profound disturbance of autonomic function. ⋯ A wide range of neuropathies are associated with lesser degrees of autonomic dysfunction. These include hereditary neuropathies, and neuropathies associated with metabolic disturbances, alcohol abuse, malignancy, medications, infections, and connective tissue disorders.
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Neuropathic pain in rats is associated with altered nitric oxide synthase activity in neural tissue.
Peripheral nerve injury may lead to a chronic neuropathic pain state that results from an increase in excitability of central neurons. This central sensitization is mediated via an N-methyl-D-aspartic acid (NMDA) receptor and may involve the production of nitric oxide (NO). As NO is suggested to play a role in nociceptive transmission following nerve injury, we examined for altered NO synthase activity at multiple levels of peripheral and spinal neural tissue in a rat model of neuropathic pain. ⋯ An increase in NOS activity in the DRG may be an early mechanism for inducing more central changes. The bilaterally decreased NOS activity in the lumbar spinal cord may be secondary to a negative feedback mechanism resulting from increased NO production in the spinal dorsal root ganglia. Multiple alterations in expression of NOS activity that occur in both peripheral and central processing may play a role in the pain behavior resulting from peripheral nerve injury. (Preliminary results of these studies have been presented in abstract form at the annual meetings of the Society for Neuroscience, 1994, and the American Society of Anesthesiologists, 1994).