Quantitative measurement of pain sensation in patients with Parkinson disease.

BACKGROUND: Pain is common in patients with Parkinson disease (PD) and can precede the diagnosis of the disease. Experimental studies and clinical evidence indicate involvement of basal ganglia and dopaminergic pathways in central pain processing. OBJECTIVE: To quantitatively assess and compare pain perception in patients with unilateral PD with and without pain and in patients with response fluctuations. METHODS: Thirty-six patients with PD (mean age, 61.8 +/- 11.2 years) with predominantly unilateral disease, 15 patients with response fluctuations (mean age, 65.3 +/- 10.4 years), and 28 age-matched healthy control subjects participated in the study. Subjective pain was assessed using the visual analog scale with von Frey filaments for tactile thresholds and contact thermode for warm sensation (WS) and heat pain thresholds (HPTs). RESULTS: Tactile and WS thresholds did not differ between patients in both patient groups and control subjects nor between sides. HPT was lower in patients with PD who experienced pain (n = 21) compared with those who did not (42.6 +/- 3.0 degrees C vs 45.6 +/- 2.8 degrees C; p < 0.01) and those who experienced pain in the more affected side (41.4 +/- 2.6 degrees C vs 43.7 +/- 3.3 degrees C; p < 0.0001). In patients with fluctuations there were no side differences in WS and HPT or between "on" and "off" periods. CONCLUSION: Endogenous pain in patients with Parkinson disease is accompanied by increased sensitivity to some painful stimuli, suggesting that basal ganglia abnormality also involves pain encoding.

Electrical activity from rat corpora is affected by pharmacological but not mechanical intracorporal manipulation.

Smooth muscle electromyographic (EMG) recording from the corpora cavernosa is a potentially useful clinical tool for the diagnosis of impotence. Controversy still exists regarding the nature of this signal, which could be resolved using animal models. The signal recorded from denuded rat corporal surface was Fourier transformed, and power at 0.01-1 Hz was calculated. Measurements were taken in the flaccid state and during erection induced by intracorporal injection of smooth muscle relaxants [the phosphodiesterase inhibitors papaverin and isobutylmethylxanthine (IBMX)]. Recorded activity decreased significantly during the pharmacologically evoked erection: the mean square root power of 250.7+/-137.1 microV decreased to 49.8+/-14.1 microV (P<0.0001) after papaverin, and IBMX caused it to decrease from 222.8+/-132.0 microV to 58.1+/-40.8 microV (P<0.0001) (mean +/- SD). Intracorporal injection of adrenaline partially reversed the response, increasing activity to 135.3+/-72.3 microV (P=0.01) and 137.5+/-122.6 microV (P=0.015), respectively, in parallel with detumescence. In order to rule out a mechanical artefactual explanation for these results, recording was also performed before and during artificial erection induced by the intracorporal infusion of saline. This manipulation did not cause any change in corporal activity, despite corporal engorgement and increased pressure. In conclusion, the signal indeed reflects changes in the tone of corporal smooth muscle, and therefore should be regarded as a genuine EMG recording.

DC photoplethysmography in the evaluation of sympathetic vasomotor responses.

The d.c. component of the photoplethsmographic signal was used to determine the response of the finger vasculature to three standard tests of vasomotor function: (1) an inspiratory gasp (IG), (2) immersion of the contralateral hand in ice water (IW), and (3) the Valsalva manoeuvre. The vasoconstrictor response to the first two of these stimuli could be measured in all of 25 normal subjects. The response to the Valsalva manoeuvre could not be detected consistently. Seven patients with known sympathetic autonomic dysfunction showed no response to either IG or IW. In 30 patients with diabetes mellitus of over 10 years duration, 46.7% had no response to IG, and 20% had no response to IW. Absent responses correlated with abnormal autonomic cardiovascular reflexes, with absent sympathetic skin responses and with the severity of peripheral somatic neuropathy. The d.c. photoplethysmographic determination of the vasoconstrictor response in the finger after a deep inspiratory gasp and after ice water immersion offers an additional measure of the function of small (2 mu-6 mu) peripheral nerve fibres. Because of variability in the amplitude of the responses in normals, only an absent response should be accepted as abnormal.

The effects of long-term lead intoxication on the nervous system of the chicken.

In order to study the possible etiologic role of lead in human motor neuron disease we produced chronic lead intoxication in the chicken by daily administration of lead acetate. Control animals received sodium acetate. During life, periodic measurements were made of motor function, motor nerve conduction velocity and response amplitude. After sacrifice, histologic analysis was performed on spinal cord, peripheral nerve and muscle. A syndrome was produced characterized by a fall in motor response amplitude, spinal motor neuron degeneration, motor axonal loss and atrophy of muscle, similar to that seen in human motor neuron diseases.

Automatic scoring of polygraphic sleep recordings: midazolam in insomniacs.

Midazolam in doses of 0.21-0.46 mg/kg was given to four insomniacs for 27 days, and to a fifth insomniac for an additional 124 days, to assess its short, intermediate, long-term and long-standing efficacy. Automatic analysis of the polygraphic sleep recordings was carried out employing real-time signal processing (based on linear prediction), and an off-line sequential fuzzy clustering. Total sleep length did not vary significantly during medication, whereas other efficacy parameters such as sleep onset latency, wake time after sleep onset and number of nightly awakenings decreased significantly throughout the period of active medication. In one patient, midazolam was still effective after 151 days of administration. The ultrashort action (probably 3-4 h) of midazolam could be demonstrated by the distribution of the efficacy parameters, dividing the night into 2-h periods, by the unchanged total sleep length during medication compared with baseline and by the lack of any subjective clinical symptoms of hangover. The quantitative analysis of the signals showed that, although a decrease in the total amount of slow-wave sleep during long-term medication and withdrawal was detected, the total relative power in the delta band increased during drug administration. This was interpreted as redistribution of the delta activity during active medication. A lengthening of REM sleep was found during active medication probably attributable to intranight rebound. This was not followed by any clinical symptom of clinical REM rebound.(ABSTRACT TRUNCATED AT 250 WORDS)

Analog delay line artifact rejector for evoked potential studies.

A true artifact rejector which utilizes a bucketbrigade delay line is described. The delay line enables scanning of all the data in the analysis period prior to its inclusion in the average. The device is small in size, independent of the averager, and the total cost of components is under $100. This artifact rejector is compatible with any averager. Artifact rejection can be according to excessive amplitude, as described in this version, or according to externally applied signals. In addition, by a minor change in the interference detector module, rejection could be according to other criteria, such as frequency contents. The utility of the device is demonstrated on records of auditory brain stem evoked potentials.

Computerized analysis of sleep recordings applied to drug evaluation: midazolam in normal subjects.

Computerized analysis of polygraphic sleep recordings was carried out for the evaluation of midazolam, a benzodiazepine hypnotic. The analysis was carried out in real time on a small laboratory computer, and the output included the hypnogram and relative power profiles for the main electroencephalogram activities. Analysis showed a slight "intranight rapid eye movement rebound" during medication and reduction of sleep stage IV after withdrawal. The relative power of the delta frequency band did not change during medication or withdrawal.

On the prediction of epileptic seizures.

In 12 epileptic patients suffering from "absences" 8-channel EEG was recorded by telemetry. The autoregressive model was applied to the signal and the prediction coefficients being the basis for calculation of the poles of the predictor. The location of the poles in the z- and s-planes was described as a function of time for 0.1 s steps along the pre-seizure EEG. In 10 of the 12 patients, and in 25 of the 28 recorded seizures this presentation of the poles of the predictor showed specific pattern linked with the occurrence of the seizure. The trajectory of the "most mobile pole" during the pre-seizure period could aid in the prediction of the seizure by several seconds.