Painless electrodiagnostic current perception threshold and pain tolerance threshold values in CRPS subjects and healthy controls: a multicenter study.

The purpose of this study is to evaluate both painless and painful sensory transmission in patients with Complex Regional Pain Syndrome (CRPS) using the automated electrodiagnostic sensory Nerve Conduction Threshold (sNCT) test. This test generates reliable, painless Current Perception Threshold (CPT) and atraumatic Pain Tolerance Threshold (PTT) measures. Standardized CPT and PTT measures using constant alternating current sinusoid waveform stimulus at 3 different frequencies 5 Hz, 250 Hz, and 2 kHz (Neurometer CPT/C Neurotron, Inc. Baltimore, MD) were obtained from CRPS subjects at a distal phalange of the affected extremity and at an ipsilateral asymptomatic control site. Matched sites were tested on healthy subjects. Detection sensitivities for an abnormal PTT and CPT test were calculated based on specificity of 90% as determined from data obtained from healthy controls. A Spearman rank correlation was used to test for a significant association between presence of allodynia and an abnormal PTT or CPT at any frequency tested. Thirty-six CRPS subjects and 57 healthy controls were tested. The highest detection sensitivity of the PTT test from symptomatic test sites was 63% for the finger and 71% for the toe. PTT abnormalities were also detected, to a lesser degree, at the asymptomatic control site (41% finger control site, 16% toe control site). The highest CPT detection sensitivity at the symptomatic site was 37% for the finger site and 53% for the toe site. CPT abnormalities were also detected at the asymptomatic control site (29% finger control site, 37% toe control site). Eighty-six percent of the CRPS subjects had either a PTT or CPT abnormality at any frequency at the symptomatic site. There was a significant correlation between presence of allodynia and presence of an abnormal CPT and PTT, respectively (P < .01). The correlation coefficient was lower for CPT than for PTT, ie, 0.34 versus 0.6 for the finger and 0.48 versus 0.67 for the toe, respectively. In studied CRPS patients an abnormal PTT was detected with higher sensitivity than an abnormal CPT. Assessing PTT may become a useful electrodiagnostic quantitative sensory test for diagnosing and following the course of neuropathic pain conditions.

Minor traumatic brain injury: review of clinical data and appropriate evaluation and treatment.

The clinical entity of minor traumatic brain injury (MTBI) is secondary to signs and symptoms encompassing neuropathological, neurochemical, neurobehavioral, neuropsychological and behavioral deficits. The patients who suffer this disorder are often given little help, medically, secondary to issues regarding the perceived reality of the disorder. A few individuals deny the existence of MTBI. Some believe the symptom complex to be strictly functional, while others believe that spontaneous recovery will occur and no treatment is necessary. When discussing traumatic brain injury the descriptors, "mild, moderate, and severe," are used to describe the severity of the acute injury. These labels do not describe the severity of the sequelae nor are they indicative of the intensity of specific treatment. A clear understanding of MTBI, its sequelae and necessary treatment is imperative to insure timely intervention. Delay or lack of early intervention appears to be responsible for "persistent sequelae" in MTBI. This paper will describe various aspects of the etiology of MTBI, with recommended evaluation and treatment guidelines. A functional assessment scale specifically for persons with MTBI is also presented. Several case histories are included for illustration purposes.

The effectiveness of physical therapy in the treatment of chronic daily headaches.

We investigated the adjunctive use of physical therapy, with the more standard modalities of medication and/or biofeedback-enhanced neuromuscular re-education, in patients with chronic daily headaches who had palpable muscle spasm in the neck and shoulder regions. Patients in group one received medication detoxification (when necessary), amitriptyline and (in some cases), biofeedback. Patients in group two received detoxification (when necessary), amitriptyline (in some cases) and physical therapy, including TENS (transcutaneous electrical nerve stimulation). Patients in group three received detoxification (when necessary), amitriptyline in (some cases), and TENS without other modalities of physical therapy. Patients in groups two and three, as judged by changes in Headache Index, showed a significantly faster and greater decline in headaches than patients in group one, and maintained this excellent relief through the six month follow-up period. From a biochemical perspective, this improvement may be related to the demonstrable increase in serotonin levels that attends TENS. From a behavioural perspective, improvement may be related to the change in "locus of control" from the headache to the patient that attends the more "active" modalities of TENS and physical therapy, as opposed to the more "passive" modality of medication alone.

Sudden unexpected death associated with seizures: analysis of 66 cases.

We have analyzed 66 cases of sudden unexpected death (SUD) in persons with seizure disorders, which were examined by the Office of the Medical Examiner, Cook County (Chicago), Illinois. The individuals ranged in age from 10 months to 60 years (mean age, 28 years). Autopsy findings were insufficient to explain death, and there was no evidence of major systemic pathology. Approximately 40% of victims were found dead in bed, and the remainder in some other room at home, apparently having been engaged in normal activity. Several died in an emergency room following a seizure at home. Cardiopulmonary resuscitation was attempted but was ineffective. Neuropathological examination revealed brain lesions, which probably caused the seizures, in 60% of the cases. In 68% the anticonvulsant blood level was subtherapeutic or below detectable levels. The prevalence of seizure-associated SUD may be between 1:525 and 1:2,100 among epileptics. The mechanism of death in these cases probably involves cardiac arrhythmias mediated by sympathetic autonomic events occurring during the seizure.

The anesthetic effect of air at atmospheric pressure.

Nitrogen has recognized narcotic potential at hyperbaric pressures. No narcotic effect of helium has been demonstrated at any pressure. We evaluated the effect of nitrogen in air at one atmosphere on human performance by comparing it with helium-oxygen using a four-alternative divided-attention task that requires rapid response to auditory and visual signal changes. There was a 9.3 per cent decrease in response time when subjects breathed helium-oxygen, a signigicant change (P less than 0.001). This change could not be ascribed to practice since the order of presentation of gases did not have a significant effect. It concluded that the nitrogen in ambient air slightly but measurable impairs human performance compared with a non-anesthetic gas such as helium.