Facioscapulohumeral dystrophy, retinal vasculature, and Sneddon's syndrome.
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Cerebrovascular Disorders↗
Biomedical subjects
D A Ingram
Publications and source records attributed to D A Ingram.
Mirror movements studied in a patient with Klippel-Feil syndrome.
1. Electromyographic (EMG) recordings have been made from upper limb muscles in a patient with well-defined congenital mirror movements occurring in association with Klippel-Feil syndrome and the results compared to those obtained in normal control subjects. 2. In the patient, liminal percutaneous electrical or magnetic brain stimulation applied over either hemisphere elicited bilateral and symmetrical short-latency muscle responses in relaxed intrinsic hand muscles. In the normal subjects unilateral brain stimulation only elicited contralateral muscle responses. 3. F response and H reflex studies for the patient's ulnar-supplied intrinsic hand muscles were normal. No crossed responses were recorded in the homologous muscles of the contralateral hand. 4. Scalp-recorded somatosensory-evoked responses following ulnar or median nerve stimulation were of normal latency and distribution in the patient. 5. In the patient, cross-correlation analysis of on-going single and multiunit needle EMGs recorded between muscles of left and right hands revealed a central peak in the cross-correlogram. No cross-correlogram peaks were found between left- and right-hand muscles in normal subjects. The magnitude and time course of the central peaks in the cross-correlograms constructed between the firing of motor units on opposite sides of the body in the patient were similar to those found in cross-correlograms constructed between the firing of motor units from muscles on the same side of the body in the patient and in normal subjects. 6. The magnitude of cross-correlogram peaks detected within a muscle and those detected between left and right homologous muscles showed a gradient in which the largest peaks were found in the intrinsic hand and forearm extensor muscles. The smallest peaks were observed in the forearm flexor muscles. No peaks were detected between left and right biceps brachii muscles. In intrinsic hand muscles, the size of the cross-correlogram peak detected between the EMGs of homologous muscle pairs was greater than that found for non-homologous muscle pairs. 7. Cutaneous reflex responses were recorded from first dorsal interosseous muscle following unilateral electrical stimulation of the digital nerves of the index finger. In the patient, this produced an early excitatory (E1) response on the stimulated side. Later excitatory (E2 and E3) responses, of approximately equal size and latency, were distributed bilaterally. In the normal subjects, reflex responses were confined to the stimulated side.(ABSTRACT TRUNCATED AT 400 WORDS)
Arm↗
On the localization of the stretch reflex of intrinsic hand muscles in a patient with mirror movements.
1. The patient studied showed the typical mirror movements of the Klippel-Feil syndrome. Earlier intensive electrophysiological analysis suggests that many of her corticospinal axons branch abnormally to supply motoneurones on both sides of the spinal cord. Thus, in her, a long-latency reflex utilizing the motor cortex should manifest itself bilaterally. 2. EMG recordings were made simultaneously from the first dorsal interosseous (FDI) muscles of both hands while they were being voluntarily activated by the subject. The FDI of one hand was then briefly stretched by forcibly adducting the index finger. Similar but more limited studies were made using flexor pollicis brevis. 3. The reflex response of the stretched muscle consisted of a typical mixture of early (M1) and late (M2) components, with mean latencies of 32 and 49 ms respectively. 4. Unlike normal controls, the contralateral muscle responded on stretch of the ipsilateral muscle. However, its response consisted solely of a long-latency reflex. This was comparable in size, latency and waveform to the ipsilateral late component. (Mean size, 84% of the ipsilateral M2 response; mean latency 46 ms, or 3 ms less than the ipsilateral response due to the absence of M1). 5. The short-latency response did not spread to the homologous contralateral muscle even when it was large ipsilaterally. The long-latency response elicited from FDI did not spread to the abductor digiti minimi muscle of either hand. 6. Reducing the duration of the stretch reduced the duration of the crossed response by an equivalent amount. Unloading the ipsilateral muscle produced a delayed reduction of EMG activity contralaterally. Thus her long-latency pathway can act tonically as well as phasically. 7. These findings strongly support the hypothesis that delayed components of the human stretch reflex are relayed via the motor cortex and the corticospinal tract.
Electromyography↗
Electrophysiology of motor pathways for sphincter control in multiple sclerosis.
The central and peripheral motor pathways serving striated sphincter muscle function were studied using cortical and lumbar transcutaneous electrical stimulation, pudendal nerve stimulation and sphincter electromyography in 23 patients with multiple sclerosis (MS), and sphincter disturbance, including incontinence of urine or faeces, urinary voiding dysfunction, or constipation. The central motor conduction time was significantly increased in the MS group compared to controls (p less than 0.05). Damage to both the upper and lower motor neuron pathways can contribute to sphincter disturbance in MS. The latter may be due to coexisting pathology or to involvement of the conus medullaris by MS.
Adult↗
Polysaccharide storage myopathy.
In a woman with a slowly progressive adult onset proximal myopathy, muscle biopsy showed storage of PAS positive material in type 1 fibers. This material consisted of a branched chain polysaccharide associated with a mucoprotein. No abnormality of glycogen-pathway enzymes was detected. This suggested that this polysaccharide accumulation occurred because the polysaccharide was laid down in a non-bioavailable form. The clinical and histochemical features in this patient and in the few similar reported cases indicate that polysaccharide storage myopathy is a distinct entity that is allied to the glycogen storage myopathies.
Electromyography↗
Jitter correction: a computer algorithm for reduction of the velocity recovery function artifact.
The measurement of neuromuscular jitter in single fiber electromyography may be artifactually raised by a component of interdischarge interval (IDI)-dependent jitter caused by the velocity recovery function (VRF) in muscle fibers. We have developed a computer algorithm for on-line mathematical correction for this artifact, thus improving the reliability of neuromuscular jitter estimates. The method, based on a modeling technique, was validated using intramuscular stimulation in order to either exclude an IDI-dependent component (using regular stimulation) or to include an IDI-dependent component (using pseudorandom stimulation). In 10 normal subjects the distribution of 106 corrected jitter values obtained using voluntary activity showed no difference from the measured values. This finding implies that previously published values for normal jitter are not likely to have been influenced by the VRF effect.
Action Potentials↗
Patterns of selective involvement of thigh muscles in neuromuscular disease.
In 14 patients with limb girdle muscular dystrophy, polymyositis, and type 3 spinal muscular atrophy, CT scans of the thigh muscles were correlated with single fiber EMG studies in vastus lateralis, semimembranosus and biceps femoris muscles. There was a relation between the extent of CT scan abnormality and increased fiber density in the three muscles studied, except in the most severely affected muscles in which in some muscles the fiber density values were lower than expected. These results were independent of the underlying pathology. Correlative CT/SFEMG studies provide insights into the pattern of selective involvement of certain muscles in neuromuscular disorders.
Adult↗
Central motor conduction in multiple sclerosis: evaluation of abnormalities revealed by transcutaneous magnetic stimulation of the brain.
Magnetic stimulation of the brain and spinal column was used to assess conduction in the descending central motor pathways controlling arm and leg muscles of 20 patients with multiple sclerosis, and 10 normal subjects. The multiple sclerosis patients had relapsing and remitting disease but all were ambulant and in stable clinical remission. Increased central motor conduction times (CMCTs), up to three times normal, were frequently encountered in multiple sclerosis patients and in leg muscles these correlated closely with clinical signs of upper motor neuron disturbance; in the upper limb muscles a higher proportion of subclinical lesions was present. Weak muscles were almost invariably associated with abnormal central conduction but increased CMCTs were also found for 52 of the 104 muscles with normal strength. CMCTs for lower limb muscles were directly related (p less than 0.005) to functional motor disability (Kurtzke and Ambulatory Index Scales). No patient developed clinical evidence of relapse during follow-up of at least 8 months. Magnetic brain stimulation is easy to perform, painless, and safe, and provides clinically relevant information in the diagnosis and monitoring of multiple sclerosis patients.
Adult↗
Selective and asymmetric vulnerability of corticospinal and spinocerebellar tracts in motor neuron disease.
The spinal cords of 10 cases of motor neuron disease were compared with those of six age-matched controls using myelin and silver impregnation methods, and the Marchi reaction for myelin degradation products. These studies revealed striking asymmetry in involvement of the lateral and anterior corticospinal tracts, without concordance in the pattern of involvement of these crossed and uncrossed corticospinal pathways. In addition there was prominent involvement of the posterior and anterior spinocerebellar tracts, but less marked abnormality was seen in the reticulospinal pathways. These findings highlight the asymmetrical involvement of the upper and lower motor neuron components of the motor system that is a characteristic feature of the disease, and demonstrate that involvement of the spinocerebellar system is a frequent finding.
Anterior Horn Cells↗
Effect of diazepam on sleep in patients with chronic airflow obstruction.
The effect of a single dose of diazepam on sleep and respiration was studied in nine patients with chronic airflow obstruction with moderate arterial hypoxaemia but no hypercapnia. Diazepam improved sleep duration without exacerbating nocturnal hypoxaemia and there was no change in the number of apnoeic events after a single 5 mg dose at night.
Aged↗
Juvenile-onset bulbospinal muscular atrophy with deafness: Vialetta-van Laere syndrome or Madras-type motor neuron disease?
A girl with rapid-onset, bulbospinal muscular atrophy and deafness is described. The patient's mother and brother showed EMG features consistent with subclinical involvement. T is bulbospinal form of spinal muscular atrophy associated with deafness described by Vialetto and van Laere closely resembles the Madras type of motor neuron disease, also associated with deafness, described by Jagganathan and colleagues.
Adolescent↗
The double collision technique: a new method for measurement of the motor nerve refractory period distribution in man.
A new, double collision, technique is described for non-invasive measurement of the motor nerve refractory period distribution for human peripheral nerves. In contrast to previous collision techniques, this method is independent of the transient changes in nerve and muscle fibre conduction which can distort test muscle responses. The end-point of the distribution is determined by a null response; this permits accurate identification of those nerve fibres with the longest refractory periods. We have used the double collision technique to measure the refractory period distributions for the median nerve at the wrist in 20 normal subjects aged between 22 and 58 (mean 35) years. 150% maximal stimuli were used with a controlled limb temperature of 35 degrees C. Following a conditioning stimulus, the mean latencies for recovery of 5%, 50%, 95% and 99% of motor nerve fibres were 0.94, 1.03, 1.12 and 1.23 msec respectively. Data are also presented for the ulnar and peroneal nerves. The results show that the human motor nerve refractory period distribution is much less dispersed than has been previously supposed.
Adult↗
Motor nerve conduction velocity distributions in man: results of a new computer-based collision technique.
A new computer-based collision technique for direct measurement of the human motor nerve conduction velocity distribution is described. In contrast to previous collision techniques, the test muscle response is progressively cancelled to a null using an arrangement of proximal and distal stimuli which eliminates distortion of the test response caused by transient changes in nerve and muscle fibre conduction. The increased sensitivity of this new technique permits accurate measurement of the slowest 1% of alpha motor nerve fibres. We have used our modified collision technique to determine motor nerve conduction velocity distributions for the median nerve in 20 normal subjects aged between 19 and 59 (mean 35) years. 150% maximal stimulus intensities were used, with a controlled limb temperature of 35 degrees C. Group mean velocities (+/- S.D.) for the fastest (95%), mean (50%) and slowest (5% and 1%) motor fibres were 59.1 +/- 3.0, 56.9 +/- 2.9, 52.7 +/- 3.1 and 51.2 +/- 3.7 m/sec respectively. Data are also presented for the ulnar and peroneal nerves.
Action Potentials↗
Central motor conduction is abnormal in motor neuron disease.
Conduction in the central motor pathways of the brain and spinal cord was studied in 12 patients with motor neuron disease. Six healthy volunteers served as controls. Transcutaneous electrical stimulation of the cortex, cervical cord, thoracic cord and conus medullaris was used to determine motor latencies to the biceps brachii, thenar eminence and tibialis anterior muscles. Prominent, and often asymmetrical, slowing of central motor conduction was demonstrated in seven of the 12 patients; these findings were most marked in the spinal cord and in most cases correlated with clinical features of corticospinal involvement. In general it was more difficult to excite motor pathways in the central nervous system in the patients with motor neuron disease than in control subjects. Evidence of subclinical involvement of central motor pathways was found in five patients. The central lesion in motor neuron disease may thus contribute more significantly to the clinical deficit than has been realised, since the clinical signs of the upper motor neuron lesion are often masked by the more obvious lower motor neuron features.
Adult↗
Brain-stem auditory evoked responses in diagnosis of central pontine myelinolysis.
Central pontine myelinolysis (CPM) developed in association with acute adrenocortical insufficiency during correction of severe hyponatraemia in a 58-year-old woman. Repeated CT scanning and NMR imaging were normal from the onset of the illness. Electroencephalography and brain-stem auditory evoked responses showed abnormalities consistent with a brain-stem lesion, which resolved as the patient made a gradual but incomplete recovery. Our observations illustrate the value of electrophysiological monitoring in CPM and support the proposed association between this condition and the rapid correction of an electrolyte imbalance.
Adrenal Insufficiency↗
Evoked potentials during isoflurane anaesthesia.
Somatosensory, visual and brainstem auditory evoked potentials were recorded in 10 unpremedicated patients anaesthetized with isoflurane in oxygen. Recordings were made at 0.5%, 1.1% and 1.65% (six patients) end-tidal isoflurane concentration. There were statistically significant increases in the latencies of the somatosensory (N20), visual and brainstem auditory potentials (waves III and V) with increasing concentrations of isoflurane. The central conduction time was prolonged. Amplitudes of the somatosensory and visual potentials were reduced with increasing concentrations of isoflurane. The effects of isoflurane on evoked potentials are similar to those of halothane and enflurane. It is possible that changes in evoked potential measurements may be useful as a neurophysiological indicator of anaesthetic depth.
Anesthesia, Inhalation↗
Nocturnal hypoxia and sleep apnoea in asymptomatic obese men.
A disorder of breathing during sleep with a fall in arterial oxygen saturation (%SaO2) and apnoea is reported in association with obesity. In obese women an increased severity of oxygen desaturation and the appearance of sleep apnoea is often seen after the menopause whereas the factors influencing sleep-breathing patterns in obese men are uncertain. We investigated this by studying respiration during sleep in 20 asymptomatic obese men (mean wt 125 kg, age range 18-59 y) and 20 control men of normal weight (mean wt 67 kg, age range 19-67 y). In the obese men the mean awake %SaO2 measured in the supine position was significantly less than controls (obese 95 +/- 0.4, controls 97 +/- 0.2, P less than 0.01) and a greater fall in %SaO2 occurred in this group during sleep (mean asleep %SaO2 obese 90.5 +/- 0.9, controls 96 +/- 0.2, P less than 0.01). In addition, the minimum asleep %SaO2 was significantly less in the obese (mean minimum %SaO2 obese 75 +/- 3, controls 93 +/- 0.9, P less than 0.001). Sleep apnoea was uncommon and infrequent in the controls but was seen in nine obese men and was frequent throughout the night in seven of them. In the obese group increasing age and increasing obesity were not significantly correlated with an increased severity of nocturnal oxygen desaturation. We conclude that disordered sleep-breathing with marked oxygen desaturation and apnoea is a common finding in extremely obese men of all ages and suggest that this results from the mechanical impedence of breathing due to abdominal adipose tissue combined with abnormal central respiratory control.
Adolescent↗
Human corticospinal tract conduction velocity.
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Evoked Potentials, Somatosensory↗