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Biomedical subjects

D R Ayyar

Publications and source records attributed to D R Ayyar.

At least 37 records · Page 2Linked to original sources
PubMed1985

Myasthenia gravis complicating Charcot-Marie-Tooth disease: report of a case.

Generalized myasthenia gravis developed in a 61 year old man with the hypertrophic form of Charcot-Marie-Tooth disease (CMT). While ocular abnormalities mimicking myasthenia gravis have been reported in CMT, and two patients with atypical CMT have had features consistent with ocular myasthenia, this is the first report of generalized myasthenia gravis complicating CMT. The estimated prevalence for the concurrence of these two disorders suggests that it is an extremely rare event.

Adult↗
PubMed1984

Medial plantar sensory response. Sensitive indicator of peripheral nerve dysfunction in patients with diabetes mellitus.

The effects of near-normal glucose control on nerve conduction results were studied in 10 patients with insulin-dependent diabetes mellitus who underwent a six-month program of intensification of therapy. The most striking electrophysiologic abnormality was the medial plantar sensory nerve conduction response. A sensory nerve action potential could not be elicited in seven of the 10 patients at the baseline evaluation. Over the six-month period of near-normal glucose control, there was a return of sensory nerve action potential in all 10 patients. Medial plantar sensory nerve conduction responses appear to be a sensitive and early electrophysiologic indicator of peripheral nerve dysfunction in patients with diabetes mellitus. Near-normalization of plasma glucose levels by intensification of diabetes management may be accompanied by correction of this early abnormality.

Adult↗
PubMed1984

Early electrodiagnosis of the ulnar entrapment neuropathy at the elbow.

Reliable, technically not demanding, electrophysiological tests make it possible to diagnose the ulnar entrapment neuropathy at the elbow. Ulnar nerve was stimulated supramaximally at the wrist, below and above the elbow, and in the upper arm, and the sensory nerve action potential (SNAP) and compound muscle action potential (CMAP) were recorded. Sensory and motor nerve conduction velocities (SNCVs, MNCVs) were calculated in each segment. In 12 of 64 symptomatic extremities of 44 patients with a presumptive diagnosis of the ulnar neuropathy at the elbow MNCVs of all segments were within normal limit and only SNCV across the elbow was significantly slowed (p less than 0.001). In 25 extremities of the patients SNAP was not obtained. Evidence of denervation in the first dorsal interosseous and abductor digiti minimi muscles was detected in about 50% hands tested. This percentage was higher in the hands with absence of SNAP than those with presence of SNAPs. It would appear that measurement of SNCV across the elbow is a more sensitive parameter to detect abnormal conduction across the cubital tunnel in patients with the ulnar neuropathy.

Elbow Joint↗
PubMed1984

Sensory nerve conduction study in the medial antebrachial cutaneous nerve.

Sensory nerve conduction in the medial antebrachial cutaneous nerve was studied in 40 normal subjects utilizing both antidromic and orthodromic methods. Using the antidromic method the distal sensory latency to the take-off point of the sensory action potential (SNAP) was 1.54 +/- 0.17 msec, latency to the peak of the SNAP was 2.11 +/- 0.16 msec, the amplitude of the SNAP was 18.8 +/- 7.1 mu v and the nerve conduction velocity was 65.9 m/sec. Using the orthodromic method the values were 1.55 +/- 0.17 msec, 2.10 +/- 0.15 msec, 15.7 +/- 6.3 mu v and 65.5 +/- 8.5 m/sec, respectively. Amplitude of the medial antebrachial cutaneous SNAP was usually smaller than that of the lateral antebrachial cutaneous nerve (p less than 0.01). This technique should be useful in the electrodiagnostic differentiation between eighth cervical or first thoracic root involvement and postganglionic lesions including the lesions of the inferior trunk or the medial cord of the brachial plexus and also in confirming involvement of this peripheral nerve due to other focal causes.

Action Potentials↗
PubMed1984

The Eaton-Lambert myasthenic syndrome and long-term treatment with prednisolone.

A 34-year-old women with the Eaton-Lambert myasthenic syndrome was treated with prednisolone for over a year. Proximal muscle weakness and breathing difficulty due to weakness in the respiratory muscles showed improvements after long-term administration of prednisolone. Electrophysiological studies before treatment revealed decreased amplitudes of the compound muscle action potential (CMAP), a decrement in CMAP to low frequency nerve stimulation, an increment on high frequency stimulation and posttetanic facilitation over 300%. Following administration of prednisolone, these electrophysiological parameters became almost normal. This case suggests that immunosuppressive drugs such as prednisolone may have a place in the management of the patients with myasthenic syndrome, especially of those who has no evidence of malignant tumor.

Action Potentials↗
PubMed1983

Edrophonium test in Eaton-Lambert syndrome: quantitative oculography.

Accurate ocular motility recordings were made of the saccadic responses of five patients with Eaton-Lambert syndrome (ELS). It was found that, contrary to common belief, the ocular motor system is affected. The saccades of ELS patients mimicked those of patients with myasthenia gravis (MG). Both groups exhibited hypometria and multiple, closely spaced saccades. Two patients demonstrated both saccadic facilitation and positive edrophonium tests. The ELS patients had slow or normal saccadic velocities, not the "super-fast" velocities found in patients with ocular MG.

Aged↗
PubMed1983

Chronic inflammatory polyradiculoneuropathy complicated by factor VIII antibody.

A 66-year-old man with a 45-month course of chronic inflammatory polyradiculoneuropathy developed a coagulopathy due to an antibody to factor VIII. Despite clinical improvement in the neurologic disease at the onset of the coagulation disorder, antibody to peripheral nerve myelin was demonstrated in high titer. Antibodies to factor VIII and peripheral nerve myelin were both of the IgG class, but were immunologically distinct. This previously unreported association lends further credence to a disturbance in immunoregulation in chronic inflammatory polyradiculoneuropathy.

Aged↗
PubMed1983

Saphenous nerve conduction in healthy subjects.

Saphenous nerve conduction was studied in 40 healthy subjects utilizing a slight modification of the method described by Wainapel et al. The mean values obtained were as follows: distal sensory latency, 2.9 +/- 0.3 msec for 10 cm distance; conduction velocity, 46.6 +/- 3.5 m/sec; and amplitude of sensory nerve action potential, 10.7 +/- 4.3 microV. The technique should be useful in the electrodiagnostic differentiation between lumbar root (L3, L4) lesions and postganglionic lesions such as lumbar plexus and femoral nerve lesions and entrapment neuropathy of the saphenous nerve.

Action Potentials↗
PubMed1983

Electrophysiological verification of the ulnar to median nerve communications in the hand and forearm.

One hundred and fifty upper extremities of 85 unselected subjects were studied. Supramaximal nerve stimulation of the median and ulnar nerves at the wrist and elbow was used and the compound muscle action potentials (CMAPs) from the abductor pollicis brevis (APB) muscle were recorded. The ulnar to median nerve communication in the hand -- Riche-Cannieu anastomosis -- was detected in 125 out of 150 hands (83.3%). The ulnar to median nerve communication in the forearm was demonstrated in only two out of 150 extremities (1.3%). The mean ulnar nerve innervation ratio (UNIR) in the APB was 27.6 +/- 16.4% (mean +/- S.D.). In the American black population, this UNIR percentage was statistically smaller than in the American caucasian or hispanic population (p less than 0.05).

Adolescent↗
PubMed1983

Electromyographic assessment of fatiguability and recovery of orbicularis oculi in myasthenia gravis.

Orbicularis oculi fatiguability following maximal voluntary contraction and its recovery after administration of Tensilon (edrophonium chloride) were studied in 13 patients with myasthenia gravis (MG) and 8 normal controls. The number of EMG pulses per sec (C) was calculated using an experimentally manufactured EMG pulse counting system and the mean amplitude of the motor unit potentials per sec (A) was measured using the action potential analysis module (Medelec APA-6 MK-1) during maximal voluntary contraction of the orbicularis oculi muscle. Fatiguability was estimated as percentage change of C, the pre-exercise value being taken as 100%. It was 74.4 +/- 18.2% (mean +/- S.D.) in patients and was significantly different from 110.8 +/- 8.4% found in the controls (p less than 0.01). Recovery following intravenous injection of Tensilon was estimated as percentage change in C and A, the values before Tensilon injection being taken as 100%. The change in EMG pulse per sec (C) was 360.0 +/- 90.0% in MG and 113.0 + 21.2% in controls (p less than 0.005). The mean amplitude of the motor unit potential per sec (A) increased by 180.0 +/- 95.0% in MG and 120.0 +/- 42.0% in controls (p less than 0.01). This technique is thought to be valuable to confirm the diagnosis of MG when routine electrophysiological tests fail to demonstrate abnormalities in neuromuscular transmission.

Adolescent↗
PubMed1981

Hypothyroidism presenting as muscle stiffness and pseudohypertrophy: Hoffmann's syndrome.

There is a spectrum of muscular abnormalities that occurs in patients with hypothyroidism. Alterations in deep tendon reflexes are commonly observed although more extensive muscle disease is less frequently seen. Two patients who demonstrated increased muscle mass, muscle stiffness with variable degrees of muscle weakness and low levels of serum thyroxine (Hoffmann's syndrome) are described. At the time of presentation, the serum creatinine phosphokinase level was more than 10 times greater than normal, and electromyography revealed repetitive positive waves. After therapy with thyroid hormone, there was complete resolution of the muscle abnormalities, and laboratory studies were performed. In this report, we review the clinical syndrome of muscle dysfunction that can be seen with the more severe forms of hypothyroid myopathy.

Female↗