A task for assessing vertigo elicited by repetitive head movements

OBJECTIVE: We developed a simple, inexpensive test for assessing vertigo in persons with peripheral vestibular disorders. METHOD: The test was administered to 16 asymptomatic adults and 16 patients with chronic vertigo caused by peripheral vestibular disorders. Participants sat in a chair and as rapidly as possible transferred 25 beanbags one at a time from a basket placed on the floor to a basket held .91 m up in the air. The task was timed, and the participants rated the level of vertigo elicited on a 10-point scale. RESULTS: Patients took significantly more time to perform the task and reported significantly greater levels of vertigo than did the asymptomatic adults. Test scores did not differ significantly across test sessions or raters. CONCLUSION: Performance on this task reliably differentiated patients with vestibular disorders from asymptomatic adults. The test is inexpensive, takes less than 1 min to perform, and has minimal technical requirements, making it suitable for a variety of facilities and levels of staff expertise.     

On the Stability of Exponential Backoff

Random access schemes for packet networks featuring distributed control require algorithms and protocols for resolving packet collisions that occur as the uncoordinated terminals contend for the channel. A widely used collision resolution protocol is the exponential backoff (EB). New analytical results for the stability of the (binary) EB are given. Previous studies on the stability of the (binary) EB have produced contradictory results instead of a consensus: some proved instability, others showed stability under certain conditions. In these studies, simplified and/or modified models of the backoff algorithm were used. In this paper, care is taken to use a model that reflects the actual behavior of backoff algorithms. We show that EB is stable under a throughput definition of stability; the throughput of the network converges to a non-zero constant as the offered load N goes to infinity. We also obtain the analytical expressions for the saturation throughput for a given number of nodes, N. The analysis considers the general case of EB with backoff factor r, where BEB is the special case with r = 2. We show that r = 1/(1 − e⁻¹) is the optimum backoff factor that maximizes the throughput. The accuracy of the analysis is checked against simulation results.     

Vitiligo and juvenile diabetes mellitus

Five juvenile diabetics had vitiligo. In two children, the vitiligo preceded the onset of diabetes. Four of the five patients had thyroid, adrenal, or gastric antibodies or a combination of these. In three children HLA-B8 antigens were detected, and one additional patient had HLA-Bw15. Of eight nondiabetic children with vitiligo, one had abnormal glucose tolerance. To the evidence supporting an autoimmune form of diabetes mellitus we add another observation: the association of insulin-dependent diabetes and childhood vitiligo.     

Reservoir competence of the meadow vole (Rodentia: Cricetidae) for the Lyme disease spirochete Borrelia burgdorferi

The reservoir competence of the meadow vole, Microtus pennsylvanicus Ord, for the Lyme disease spirochete Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner was established on Patience Island, RI. Meadow voles were collected from 5 locations throughout Rhode Island. At 4 of the field sites, M. pennsylvanicus represented only 4.0% (n = 141) of the animals captured. However, on Patience Island, M. pennsylvanicus was the sole small mammal collected (n = 48). Of the larval Ixodes scapularis Say obtained from the meadow voles on Patience Island, 62% (n = 78) was infected with B. burgdorferi. Meadow voles from all 5 locations were successfully infected with B. burgdorferi in the laboratory and were capable of passing the infection to xenodiagnostic I. scapularis larvae for 9 wk. We concluded that M. pennsylvanicus was physiologically capable of maintaining B. burgdorferi infection. However, in locations where Peromyscus leucopus (Rafinesque) is abundant, the role of M. pennsylvanicus as a primary reservoir for B. burgdorferi was reduced.     

The local addition of tenoxicam reduces the incidence of low back pain after lumbar epidural anesthesia

BACKGROUND: Postepidural backache is a common postoperative complaint after lumbar epidural anesthesia. Useful interventions to decrease the incidence of postepidural backache would be helpful. METHODS: We performed a prospective, randomized, double-blind study to compare the effect of local addition of tenoxicam on the incidence of postepidural backache after nonobstetric surgery. One thousand unpremedicated ASA physical status I or II patients scheduled for hemorrhoidectomy were assigned randomly to tenoxicam or control groups. Patients in the control group received 25 ml lidocaine, 2%, with epinephrine 1:200,000 epidurally and 4 ml lidocaine, 1%, for local skin infiltration. Patients in the tenoxicam group received 25 ml lidocaine, 2%, with epinephrine 1:200,000 epidurally and 4 ml lidocaine, 1%, with tenoxicam (2 mg) 1:2,000 for local skin infiltration. Patients were interviewed at 24, 48, and 72 h postoperatively using a standard visual analog scale for evaluation of postepidural backache. A patient was considered to have postepidural backache when the postoperative visual analog scale score was higher than the preoperative score. RESULTS: The incidence of postepidural backache in patients in the control group for the 3 days were 22.8%, 17.4%, and 9.2%, all of which were significantly more frequent than observed in the patients in the tenoxicam group (6.8%, 4.0%, and 1.2%, P < 0.01). There was a significant association between backache and multiple attempts at epidural needle insertion. CONCLUSION: In summary, the local addition of tenoxicam reduced the incidence and severity of postepidural backache.     

Treatment of hypertrophic cardiomyopathy

The medical management of hypertrophic cardiomyopathy is reviewed. Four cases of hypertrophic cardiomyopathy are presented, and serve to describe the currently available invasive treatment modalities, i.e. septal myectomy, dual chamber pacing, cardioverter defibrillator implantation and heart transplantation. These different invasive treatments all seem to be symptomatically effective in carefully selected patients, but studies of prognostic effects are not available. Finally, new experimental procedures are presented.     

Risk factors for substance use disorders among inpatients with major affective disorders in Taiwan Chinese

The explanation by differential diagnosis of pathological changes of the fundus may be particularly difficult in case of diseases of sporadic occurrence. The examination findings in a 19-year-old patient with a choroidal osteoma are presented. Large arciform, atrophic areas with distinct boundaries and star-shaped vascular structures were dominant in the fundus on both sides. With peripapillar manifestation, the optic nerve head was ophthalmoscopically noncontributory. A submacular bleeding had caused sudden reduction of visual acuity and caused the patient to visit the ophthalmologist. The most important diagnostic key was supplied by echography, which established peripapillar scleral calcification. The posterior eye segment was highly reflective in ultrasonic echography (B mode), showing concave deformation and causing the sound shadow. Visually evoked potentials indicated the onset of the compression of the optic nerve by the choroidal osteoma. Diagnostic and treatment possibilities are discussed.