Biomedical subjects

Vera Bril

Publications and source records attributed to Vera Bril.

24 records · Page 2Linked to original sources

PubMed2002

Symmetry of nerve conduction studies in different stages of diabetic polyneuropathy.

Nerve conduction studies (NCS) in diabetic sensorimotor polyneuropathy (DSP) are sensitive, noninvasive, and associated with small coefficients of variation, and correlate well with underlying peripheral nerve morphological change. For these reasons, the current reference standard for DSP involves multivariate instruments that emphasize NCS results. However, the interside symmetry of NCS findings in different stages of DSP are unknown, although requirement for symmetry has been suggested in clinical trials of DSP. We therefore aimed to determine the degree of symmetry of NCS findings in DSP of differing severity stages. A cohort of diabetic patients, including patients without neuropathy and those with mild to severe DSP, was studied. We also studied a series of nondiabetic, healthy subjects. A variation of stratified sampling by means of a clinical neuropathy score ensured that a broad spectrum of neuropathy was studied. A total of 478 subjects was ascertained; patient accrual was discontinued when the smallest clinical group consisted of 50 subjects. Nerve conduction studies were conducted prospectively and in a blinded fashion using surface recordings, averaging for sensory action potentials, control of limb temperature, and standardized techniques. Median and ulnar motor and sensory, peroneal and tibial motor, and sural NCS were performed. Interside symmetry, independent of neuropathy severity, was observed for all investigated nerves, except for the median sensory nerve action potential amplitude, which was lower on the right side. These results confirm that abnormal NCS findings consistent with DSP are reliably symmetrical with the exception of the amplitude of the median sensory nerve action potential. Thus, unilateral evaluation of NCS in DSP is sufficient as a reference standard in clinical trials. We also conclude that great degrees of asymmetry in NCS results are reason to question inclusion of DSP patients in clinical trials.

Adult↗

PubMed2002

Diagnosis and management of diabetic neuropathy.

Diabetic sensorimotor polyneuropathy (DSP) remains the most common microvascular complication of both type I and type 2 diabetes, and poses a unique set of management challenges in the prevention of foot complications. Although different quantitative tests are available, the preliminary diagnosis of DSP can be reliably made using simple and rapid screening tests in the family physician's office or in the diabetes clinic. The Semmes-Weinstein 10-g monofilament examination is a popular, simple clinical modality for the prediction of early DSP, foot ulceration, and amputation, and, in turn, a predictor of mortality in patients with diabetes. The management of DSP is centered on optimal glycemic control, diligent foot care, and pain control as a means of preventing the progression of DSP and reducing the morbidity associated with foot complications.

Diabetic Neuropathies↗

PubMed2002

Prognostic significance of thymomas in patients with myasthenia gravis.

BACKGROUND: The presence of thymoma may be a negative prognostic factor with respect to the outcome of myasthenia gravis (MG). METHODS: Of 122 consecutive patients with MG undergoing thymectomy between August 1994 and September 2000, 37 had a thymoma. Postoperative radiation was administered to all patients with stage II thymoma and higher. To determine differences in presentation and outcome, thymoma patients were compared with patients with atrophic (n = 49) or hyperplastic (n = 36) thymus gland on final pathology. RESULTS: Thymoma patients were significantly older (52 +/- 14 vs 36 +/- 15 years, p < 0.0001) and included a significantly higher proportion of males (54% vs 28%, p = 0.006) than patients without thymoma. However, the preoperative Osserman grade and the duration of symptoms before surgery were not significantly different between groups. Mean follow-up after thymectomy was not significantly different between patients with or without thymoma (32 +/- 23 vs 37 +/- 19 months, respectively, p = 0.3). At last follow-up, the proportion of asymptomatic patients (63% vs 70%, respectively, p = 0.5) and the mean Osserman grade (0.6 +/- 0.9 vs 0.5 +/- 0.9, respectively, p = 0.6) were similar in both groups. In addition, the rate of complete remission reached 36% at 5 years in patients with or without thymoma (p = 0.8). CONCLUSIONS: Although myasthenic patients with thymoma are significantly older and include a greater proportion of males, the overall outcome, including the rate of complete remission, was similar between patients with or without thymoma. Therefore, the presence of a thymoma should not necessarily be viewed as a negative prognostic factor regarding recovery from myasthenia gravis.

Adult↗

PubMed2002

Comparison of vibration perception thresholds obtained with the Neurothesiometer and the CASE IV and relationship to nerve conduction studies.

AIMS: Vibration perception thresholds (VPTs) are used frequently to assess somatosensory pathways in clinical trials. Different equipment, testing paradigms, and stimulation sites produce varying results which make comparisons between trials and patient populations challenging. Information comparing the VPT obtained with the Neurothesiometer with that with the Vibratron is available, but not for a similar comparison with the CASE IV (computer-assisted sensory examination device). METHODS: Subjects (n = 478) including reference, non-neuropathic subjects with diabetes mellitus (DM), and diabetic patients with mild, moderate and severe diabetic sensorimotor polyneuropathy (DSP) had VPTs measured with the CASE IV and Neurothesiometer, as well as standard sural nerve conduction studies (NCS), all performed during the same half-day. The dorsum of the foot was used as the site of stimulation for the CASE IV VPT determination and the distal phalanx of the first toe for the Neurothesiometer. RESULTS: VPTs by the CASE IV and the Neurothesiometer compared moderately by linear regression analyses (R2 = 0.547, P < 0.0001), and by 95% confidence intervals. Sensitivity for the diagnosis of mild DSP was 70% with the Neurothesiometer and 49% with the CASE IV. VPTs determined by either the Neurothesiometer or the CASE IV correlated with similar agreement to the sural nerve action potential amplitude as determined by nerve conduction studies (NCS) (R2 = 0.456 and 0.461, respectively, P < 0.0001). CONCLUSIONS: The results demonstrated a significant correlation of VPT values in different stages of DSP obtained by the two methods. The Neurothesiometer was more sensitive for the diagnosis of DSP, particularly in those with mild neuropathy. Similar correlations between VPTs and electrophysiological parameters were observed, indicating that both methods are valid, and thus the Neurothesiometer may be preferable due to the ease and rapidity of testing by this method.

Adult↗

PubMed2002

Validation of the Toronto Clinical Scoring System for diabetic polyneuropathy.

OBJECTIVE: The aim of the current study was to determine the validity of the Toronto Clinical Scoring System (CSS) in reflecting the presence and severity of diabetic peripheral sensorimotor polyneuropathy (DSP) as determined by myelinated fiber density (FD) on sural nerve biopsy. RESEARCH DESIGN AND METHODS: Eighty-nine patients with both type 1 and type 2 diabetes, ascertained from a large therapeutic randomized controlled trial, were included in this cross-sectional, observational cohort study. Morphological severity of DSP was expressed as the FD in the sural nerve biopsy. The Toronto CSS was applied to all patients to determine a clinical neuropathy score. General linear regression models were used to assess the relationship between the morphological severity of DSP and the Toronto CSS. RESULTS: The Toronto CSS showed a significant negative correlation with sural nerve FD (R(2) = 0.256, P < 0.0001). The Toronto CSS was lower in those with better glycemic control (HbA(1c) </=8%). Sural nerve FD and the Toronto CSS showed strong correlations with electrophysiology, by both summed amplitude and summed conduction velocity values. CONCLUSIONS: The Toronto CSS is a valid instrument to reflect the presence and severity of DSP as measured by sural nerve morphology and electrophysiology. The results of the current study underscore the interrelationships between clinical deficits, electrophysiological findings, and morphological changes in DSP. This evidence suggests that the Toronto CSS may prove useful in documenting and monitoring DSP in the clinic and in clinical research trials.

Analysis of Variance↗

PubMed2002

Carpal tunnel syndrome in patients with diabetic polyneuropathy.

OBJECTIVE: Carpal tunnel syndrome (CTS) and diabetic polyneuropathy (DPN) are common conditions in patients with diabetes and therefore frequently occur concomitantly. Diagnosis of CTS in patients with DPN is important, as therapeutic interventions directed toward relief of CTS may be effective irrespective of diffuse neuropathy. The prevalence of clinical CTS and the most efficient electrodiagnostic discriminators of CTS from diffuse neuropathy are uncertain. RESEARCH DESIGN AND METHODS: A total of 478 subjects, including reference subjects (without diabetes and without neuropathy), nonneuropathic subjects with diabetes, and diabetic subjects with mild, moderate, and severe neuropathy, were evaluated in a cross-sectional design for clinical features of CTS. In the ascertainment of the cohort, a clinical stratification method was used to ensure a broad spectrum of neuropathy severity. All subjects underwent nerve conduction study determinations of median, ulnar, and sural nerve parameters. RESULTS: The prevalence of clinical CTS was 2% in the reference population, 14% in diabetic subjects without DPN, and 30% in those with DPN. Multiple linear regression analysis revealed that mean electrodiagnostic parameters are not significant predictors of clinical CTS in patients with diabetes. Generally, the parameters worsened with severity of neuropathy, but none reliably distinguished diabetic patients with and without CTS. CONCLUSIONS: Given the high prevalence of CTS in patients with DPN and that electrodiagnostic criteria cannot distinguish those with clinical CTS, it is recommended that therapeutic decisions for CTS be made independently of electrodiagnostic findings.

Adult↗