Multiple session experimental pain measurement.

Experimental heat pain transients were administered to 30 normal volunteers over four weekly sessions, measuring both heat pain (HP) threshold and suprathreshold magnitude estimation through VAS. Repeatability and bias for these two factors were evaluated. Heat pain thresholds measured through the method of limits were previously shown to have inter-session bias, presumably due to a practice effect. Existence of such a bias between first and second measurement sessions casts doubt on the usefulness of this parameter for pain assessment of individuals over time. In the present study, measurements of normal HP thresholds over four sessions showed that bias exists between the first and successive sessions, but not among sessions other than the first. It is concluded that (i) HP thresholds obtained from a single session are of limited value, and should be carefully interpreted. (ii) Long-term studies that use the HP threshold should take results from the second (or later) session as their baseline. The Visual Analog Scale (VAS) is considered the 'gold standard' for assessment of clinical and suprathreshold experimental pain, and changes in VAS score are regarded as significant evidence of individual response to treatment, placebo, or experimental manipulation. Although its overall group accuracy and precision have been examined for both clinical and experimental pain, and found adequate (Price 1988), the VAS has not been rigorously assessed for repeatability. Stimuli at three pain levels, 1.5, 3 and 4.5 degrees C above each individual's heat pain threshold as determined at each session, were given. Several models of analysis of the VAS were tested and repeatabilities (r) obtained from these analyses demonstrate poor precision for each of the tested analysis models. For example, inter-session repeatabilities for the three individual pain levels ranged from r = 3.8-4.7, effectively providing a confidence interval of 7.6-9.4 for any VAS reading on a 0- to 10-point scale. An examination of intra-session VAS provided somewhat better results. Thus, use of the VAS in similar experimental settings is called into question. The use of the VAS in clinical settings, where individual assessments are necessary, is also called into question, but remains to be specifically tested.

Heat pain thresholds: normative data and repeatability.

Measurement of thresholds for heat-induced pain was performed on 106 normal subjects, at thenar eminence and foot dorsum, using the reaction time-inclusive method of limits. Tests were repeated 2 weeks following the first test for most of the subjects. After determination that there were no outlying data points and that there was no systematic relationship between magnitude and variability of test scores, data from between 72 and 76 subjects were used to define normal upper and lower ranges by age, as well as repeatability coefficients. This was done through ANOVA-based procedures that extend standard repeatability assessment methods. Normative data tables are presented, with measures of repeatability for the various sites and modalities. For the conventional test range, reaching 55 degrees C, measurement of heat pain thresholds can define both hyper- and hypoalgesia. Application of repeatability coefficients allows for intra-individual inter-session comparison in longitudinal studies.

SPECT diagnosis of Creutzfeld-Jacob disease.

SPECT with 99mTc-HMPAO was performed on a 65-yr-old patient with Creutzfeld-Jacob disease. Cerebral blood flow was heterogeneously decreased throughout the brain, differing from the pattern observed in other common types of dementia. These results suggest that HMPAO-SPECT may provide useful information in the differential diagnosis of dementia, specifically when Creutzfeld-Jacob disease is suspected.

Polyneuropathy in impotence.

Three hundred and forty-one consecutive impotent patients were evaluated for the presence of polyneuropathy (PNP) by neurophysiological and psychophysical tools, including nerve conduction and quantitative sensory tests (thermal and vibratory). PNP was present in 38% of diabetics, and 10% of non diabetics. Overall, PNP was found in 19% of impotent patients. PNP is relatively common among impotent patients, and might play a causative role. Patients judged 'neurogenic' and those judged 'vasculogenic', based on nocturnal tumescence test (NPT) and vasoactive drug injection tests, had very similar rates of PNP (21 and 23%, respectively). Thus it is suggested that the vasoactive drug injection test does not serve in discriminating neurogenic from non-neurogenic impotence. NPT, however, faithfully discriminates psychogenic from organic impotence, as far as PNP is involved, since a very low percentage of patients with normal NPT had PNP.

Variance of sensory threshold measurements: discrimination of feigners from trustworthy performers.

Sensory threshold measurements are criticized as subjective and therefore not to be relied upon in clinical diagnostic practice, particularly when deliberate deception by the patient is suspected. In an attempt to devise a method which permits dependable sensory threshold interpretation, individual variability of thresholds was examined in normal and neuropathic subjects. Normals were also instructed to feign sensory impairment resulting from hypothetical injury. For each subject, a number of threshold readings were averaged, yielding individual means and variances. Feigning normal subjects evidenced a larger variance compared to trustworthy normal and neuropathic subjects. Thus, alertness to variance reinforces the psychophysical analysis: small variance values suggest trustworthy normal or pathological results, whereas large variance calls the interpreter's attention to feigned results or inattentive test performance.

Monitoring of the extracranial and intracranial course of single emboli of cardiac origin: a preliminary report.

Simultaneous monitoring of emboli in extracranial and intracranial arteries recorded with identical probes, in a patient with an artificial cardiac valve, allowed the identification and characterization of pairs of signals, which most likely represent single emboli flowing through the common carotid artery into the middle cerebral artery. This technique offers new insight into emboligenesis with obvious therapeutic implications.

Coronary artery bypass grafting (CABG) after initially successful percutaneous transluminal coronary angioplasty (PTCA): a review of 17 years experience.

OBJECTIVE: Patients who undergo successful percutaneous transluminal coronary angioplasty (PTCA) may subsequently require operative myocardial revascularization. This review examines whether prior successful PTCA alters outcomes following subsequent coronary artery bypass grafting (CABG). The costs of interventional cardiology procedures and definitive surgery were also examined. METHODS: From January 1981 through December 1997, 361 patients underwent CABG following initially successful PTCA (interval group). This group was compared with 11,909 patients who underwent CABG as the primary intervention for coronary artery disease (control group). RESULTS: The average time interval to CABG following initial PTCA was 13.7 months. The post-CABG myocardial infarction rate was 4% for patients in the interval group and 3% for patients in the control group. The 30-day mortality was similar for both patient groups (2%). For the interval group, the average cost of total interventional management was 24,220 dollars per patient. This included average costs of 13,873 dollars for CABG and 10,347 dollars for all preoperative interventional cardiology procedures. CONCLUSION: There is little doubt that PTCA procedures may provide successful myocardial revascularization. However, these procedures often need to be repeated over time and may serve only to delay coronary surgery, at substantial financial and personal cost.

Ludwig's angina: report of a case and review of management issues.

Ludwig's angina, although uncommon, remains a potentially life-threatening condition because of the risk of impending airway obstruction. Effective treatment is based on early recognition of the clinical process, with the appropriate use of parenteral antibiotics, airway protection techniques, and formal surgical drainage of the infection. We present a case of Ludwig's angina together with a brief review of the relevant literature.

Autonomic consequences of cerebral hemisphere infarction.

BACKGROUND AND PURPOSE: Recently, supraventricular tachycardia has been reported following right hemisphere stroke, suggesting a reduction in parasympathetic cardiac innervation after stroke of the right hemisphere. We performed power spectrum analysis of fluctuations in RR interval duration in the electrocardiogram in an attempt to determine how ischemic stroke influences autonomic cardiac innervation. METHODS: Power spectrum analysis of the variation in 256 consecutive electrocardiographic RR intervals was performed using the fast-Fourier transformation. The area under the spectral curve from 0 to 0.5 Hz and the area under the portion of the curve produced by parasympathetically mediated respiratory variations were determined in 20 patients with right-hemisphere and 20 patients with left-hemisphere ischemic stroke confirmed by computerized tomography. Data were compared with 40 age- and sex-matched healthy controls. RESULTS: Total cardiac autonomic innervation was reduced after a stroke of either hemisphere without regard to laterality. Cardiac parasympathetic innervation was reduced after stroke of either hemisphere with a significantly greater reduction after stroke on the right (P = 2.9 x 10(-5). CONCLUSIONS: Power spectral analysis of heart rate variability can detect autonomic consequences of stroke. The spectral data predict that, to the degree that cardiac arrhythmia is produced by unbalanced cardiac autonomic activity favoring the sympathetic system, such arrhythmias could be seen after stroke of either hemisphere and would be more common after cerebral infarction on the right. This is consistent with evidence from the recent literature.

Two mutated HEXA alleles in a Druze patient with late-infantile Tay-Sachs disease.

Two affected HEXA alleles were found in an Israeli Druze Tay-Sachs child born to first-cousin parents. His paternal allele contained two adjacent changes in exon 5: delta496C, which resulted in a frameshift and premature termination codon 96 nucleotides downstream, and 498C-->G, a silent mutation. The maternal allele had a 835T-->C transition in exon 8 (S279P). Phosphoimaging quantitation of the parents' RNAs showed that the steady-state levels of mRNAs of the mutant exons 5 and 8 were 5% and 50%, respectively, of normal levels. The exon 5 mutated allele with the premature translation termination resulted in severe deficiency of Hex A. Transient expression of the exon 8 mutated alpha-chain cDNA in COS-1 cells resulted in deficiency of enzymatic activity. The child exhibited a late-infantile-type disease.

Brain abscesses: the lung connection.

Pulmonary arteriovenous fistulas are uncommon abnormalities of capillary development which cause right to left shunting and, if not treated, may lead to severe neurological complications, including meningitis and brain abscess. Pulmonary arteriovenous fistulas are commonly a result of hereditary haemorrhagic telangiectasia (Rendu-Osler-Weber disease) and both conditions may be readily diagnosed by careful history taking and physical examination. Two cases of brain abscess associated with hereditary haemorrhagic telangiectasia, which remained unrecognized for many years, are reported. These cases emphasize the importance of early diagnosis and treatment of pulmonary arteriovenous fistula in preventing central nervous system infections.

Bronchopulmonary sequestration supplied by the coronary circulation associated with a right-sided aortic arch.

Bronchopulmonary sequestration is an uncommon congenital anomaly. Although systemic arterial supply to the abnormal lung tissue is usually derived from the aorta, other nutrient vascular sources have also been described, including, infrequently, the coronary circulation. A right-sided aortic arch is another rare vascular abnormality, generally present in the setting of a vascular ring. We report a case of pulmonary sequestration receiving arterial supply from the right coronary artery, in the presence of a right-sided aortic arch, a constellation of anomalies not previously described.

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.

Normal-pressure hydrocephalus associated with spinal cord tumor.

While the association of spinal cord tumor and high-pressure hydrocephalus is well known, only 5 cases of spinal cord tumor associated with normotensive hydrocephalus have been reported. Two further cases are described here, discussing the possible pathophysiological mechanism. It is suggested that these patients go through a subclinical stage of high-pressure hydrocephalus and become normotensive later on, a process which might influence the surgical results.

P300 and stress in mild head injury patients.

OBJECTIVE: The P300 component of event-related potentials is affected by personal meaningfulness of the stimulus to the subject. Thus, the P300 component could provide an objective parameter in the emotional assessment of road accident mild head injury patients, when exposed to relevant stimuli. METHODS: Thirteen patients with post-traumatic symptoms and 14 healthy controls were evaluated in this study. Two word types, distinguished by color, were presented on a computer screen in active 'oddball' paradigm conditions. In the first subtest, the targets were accident-related (stressful) words; in the second subtest, the targets were non-accident-related (neutral) words. Target (20%) and non-target (80%) were defined by word color. Data recorded from Pz were analyzed for P300 parameters. RESULTS: Patients and controls differed in their reaction to word types (group x word main effect P = 0.0089), regardless of the oddball presentation. Overall, accident-related words produced a significantly larger P300 wave than neutral words in patients (P = 0.0001), but not in controls (P = 0.5741). Significant correlation was found between combined P300 amplitude difference (all stressful words vs. all neutral words) and the patient's Zung state anxiety score (r = 0.68, P = 0.01). CONCLUSION: We suggest the P300 component can provide a useful, objective tool in the assessment of mild head injury patients.

Neonatal bilateral diaphragmatic paralysis caused by brain stem haemorrhage.

We describe a neonate with severe bilateral diaphragmatic paralysis caused by haemorrhage in the lower brain stem. To our knowledge this association has not been previously reported in the English medical literature.

Guillain-Barré syndrome in three siblings less than 2 years old.

Three of five children who were born to consanguineous parents developed Guillain-Barré syndrome before they were 3 years old. The syndrome is rare in early childhood and we suggest that there may be a genetic element in the pathogenesis.

Pain-evoked potentials: what do they really measure?

Cerebral evoked potentials (EPs) in response to painful stimuli have been recorded since the 1970s. Based on the apparent relationship of the response amplitude to intensity of stimulation, these potentials are conventionally interpreted as reflecting the sensory-discriminative aspects of pain. As such, pain-EPs provide an objective measure for sensation of pain. An alternative interpretation regards the pain-EP as comprised of at least two overlapping components, one pain-specific, the other, a P300 wave. In the case of pain, the P300 may reflect the degree of discomfort or unpleasantness, thus reflecting the emotional-motivational aspect. To establish the nature of the pain-EP, mini doses of a benzodiazepine, counterbalanced with placebo, were given to 6 normal volunteers. Benzodiazepines decrease anxiety, and so diminish the emotional response to pain, but they have no analgesic effect. In all subjects, pain perception was unchanged, while the EP wave was almost completely obliterated. We conclude that the pain-EP reflects the emotional-motivational response to pain rather than the sensory-discriminative. Thus, it provides a useful neurophysiological tool for studying the emotions associated with pain.

Ultrastructural pathology with normal light microscopy of liver in Wilson's disease. A case report.

Light microscopy findings in early Wilson's disease (hepatolenticular degeneration) may be normal even when special cytochemical stains are used. We present a case of Wilson's disease in which light microscopy was negative, while electron microscopy showed the characteristic changes in the hepatocytes. Since low serum ceruloplasmin levels and high urinary copper excretion are not by themselves definite proof of Wilson's disease, and since copper content of the liver is not universally measured, electron microscopy examination of liver tissue appears to be a worthwhile additional tool for the early diagnosis of Wilson's disease.