Second lumbrical-interossei latency difference: A strong predictor of median neuropathy at the wrist in uremic patients.

PURPOSE: Hand symptoms in uremic patients on dialysis can occur due to peripheral neuropathy, median neuropathy at wrist (carpal tunnel syndrome) or a combination. Routine electrophysiological parameters for diagnosing carpal tunnel syndrome do not differentiate median neuropathy at wrist in cases with concomitant peripheral neuropathy. Measuring 2L-INT latency difference has been described as the most sensitive test in establishing median neuropathy at wrist in cases with severe carpal tunnel syndrome and concomitant peripheral neuropathy. This study tested the significance of 2L-INT latency difference as a predictor of median neuropathy at wrist in uremic patients on dialysis. METHODS: 80 consecutive cases (158 hands) of end-stage renal failure on either hemodialysis or peritoneal dialysis were subjected to routine electrophysiological studies for carpal tunnel syndrome. 2L-INT latency difference was measured in all cases. RESULTS: 132/158 hands (83.5%) had abnormal electrophysiological studies. Routine tests were consistent with neurophysiological carpal tunnel syndrome in 66 (41.8%) hands and 63 of these 66 (95.5%) had prolonged 2L-INT latency difference. Peripheral neuropathy was found in 66 (41.8%) hands but 59 out of these 66 (89.4%) had prolonged 2L-INT latency difference suggesting a concomitant median neuropathy at wrist. Routinely performed tests would have missed median neuropathy at wrist with concomitant peripheral neuropathy in 59 (37.3%) hands. Overall, the incidence of median neuropathy at the wrist in our uremic patients on maintenance dialysis using standard nerve conduction parameters was 41.8%, however the incidences increased substantially to 79.1% if 2L-INT latency difference is included in the criteria for the diagnosis. CONCLUSIONS: Median neuropathy at wrist is common in patients with end-stage renal failure patients on dialysis. Diagnosis of median neuropathy at wrist is difficult in the presence of peripheral neuropathy when using the routine electrophysiological tests. Second Lumbrical-Interossei latency difference is a sensitive electrophysiological test to predict median neuropathy at wrist in presence of peripheral neuropathy.

Headaches and the N95 face-mask amongst healthcare providers.

BACKGROUND: During the 2003 severe acute respiratory distress syndrome epidemic, healthcare workers mandatorily wore the protective N95 face-mask. METHODS: We administered a survey to healthcare workers to determine risk factors associated with development of headaches (frequency, headache subtypes and duration of face-mask wear) and the impact of headaches (sick days, headache frequency and use of abortive/preventive headache medications). RESULTS: In the survey, 212 (47 male, 165 female) healthcare workers of mean age 31 years (range, 21-58) participated. Of the 79 (37.3%) respondents who reported face-mask-associated headaches, 26 (32.9%) reported headache frequency exceeding six times per month. Six (7.6%) had taken sick leave from March 2003 to June 2004 (mean 2 days; range 1-4 days) and 47 (59.5%) required use of abortive analgesics because of headache. Four (2.1%) took preventive medications for headaches during this period. Multivariate logistic regression showed that pre-existing headaches [P = 0.041, OR = 1.97 (95% CI 1.03-3.77)] and continuous use of the N95 face-mask exceeding 4 h [P = 0.053, OR = 1.85 (95% CI 0.99-3.43)] were associated with development of headaches. CONCLUSIONS: Healthcare providers may develop headaches following the use of the N95 face-mask. Shorter duration of face-mask wear may reduce the frequency and severity of these headaches.

The NORSE (new-onset refractory status epilepticus) syndrome: defining a disease entity.

INTRODUCTION: To characterise a homogeneous group of patients with new-onset refractory status epilepticus (NORSE syndrome). MATERIALS AND METHODS: This is a descriptive, semiprospective review of all cases of NORSE syndrome seen between 2000 and 2004 at a tertiary care public hospital in Singapore. A review of the literature was performed to identify possible additional similar cases for comparison. RESULTS: Seven patients with NORSE syndrome were identified. Characterising features were female gender, young age, previous good health, cerebrospinal fluid pleocytosis (in 4), antecedent febrile illness (in 5), extraordinarily prolonged status epilepticus (average 32 days), failure of extensive investigations to reveal an underlying cause, catastrophic outcome as well as temporal lobe and leptomeningeal abnormality on brain magnetic resonance imaging. A review of the literature identified 12 similar patients, comprising both adults and children. CONCLUSIONS: Based on our patients and those described in the literature, we characterise the NORSE syndrome. Increased recognition of this clinical entity is needed to help delineate the underlying aetiology of this unique severe illness.

An auditory vigilance task for mental fatigue detection.

An Auditory Vigilance Task (AVT) as a validation criterion for monitoring mental fatigue was proposed in this study. The biological basis of this task design is on the understanding that mental fatigue is a cortical deactivation. This AVT is simple to perform, free of learning curve and independent on acquired skills (aptitude, knowledge). The validity and sensitivity of this task was verified by a scientifically controlled 25-hour fatigue experiment recorded by Electroencephalogram (EEG). Results showed that this AVT is highly sensitive to changes during fatigue process. The effectiveness of this AVT was compared to one subjective rating scale (FSS). The 5-level fatigue EEG datasets (labeled by AVT and FSS respectively) were fed into Support Vector Machines (SVM). SVM test accuracy indicated that AVT is more effective than subject's own estimation. The results demonstrate conclusively that this AVT is suitable for fatigue detection study as a reliable validation criterion.