Combining cutaneous silent periods with quantitative sudomotor axon reflex testing in the assessment of diabetic small fiber neuropathy.

OBJECTIVE: Routine electrophysiological testing is often normal in the evaluation of painful diabetic neuropathy, as it is unable to detect dysfunction of thinly myelinated (Aδ) and unmyelinated (C) small fibers. Although cutaneous silent periods (CSP) and quantitative sudomotor axon reflex testing (QSART) respectively evaluate these fiber types in the extremities, these two tests have yet to be assessed together. METHODS: 26 patients with a clinical diagnosis of small fiber neuropathy (SFN) and 26 age-matched controls were assessed. Nine patients had Type I diabetes, nine had Type II diabetes, and eight had impaired glucose tolerance. The CSP onset latency and duration were recorded in each extremity. QSART was performed on the right side. RESULTS: 58% (15/26) of patients had abnormal sweat volumes obtained from QSART, while 50% (13/26) of patients had abnormal CSP responses. Combining these two tests increased the sensitivity of testing to 77% (20/26). Abnormalities were seen equally across all patient groups. CONCLUSIONS: Combining CSP with QSART significantly increases the sensitivity of testing when assessing patients with SFN related to diabetes, or prediabetes. SIGNIFICANCE: For clinically suspected SFN, it is preferable to test more than one small fiber type, as each possess different structural and functional properties and may be heterogeneously affected between patients.

Clinical experience with using lacosamide for the treatment of epilepsy in a tertiary centre.

OBJECTIVE: Lacosamide is approved for the adjunctive treatment of partial-onset seizures in adults. Phase II/III clinical trials suggest that it is a safe, effective and well-tolerated medication. However, there is little post-marketing information available about this medication. METHODS: We report our clinical experience from a tertiary referral epilepsy centre, which has been using lacosamide for the past 18 months, with 128 patients treated during this time. RESULTS: Fifty-three patients (41%) achieved at least a 50% reduction in seizure frequency, with 14 patients (11%) achieving seizure freedom for a mean time of 35 weeks. This 50% responder rate matches, and the seizure free rate outperforms that seen in previous pooled trials. The efficacy of lacosamide did not vary with concurrent sodium channel blocking agent (SCB) use, and a statistically significant dose-dependent response was not shown, which is in contrast to previous trials. Treatment emergent adverse effects (TEAEs) were noted in 52 patients (41%), with 24 patients (19%) discontinuing the medication. TEAEs were more frequent in patients on concurrent SCBs, affecting 51% vs. 28% of patients not on other SCBs. This increased risk of TEAEs from concurrent SCB use was of statistical significance (P = 0.01). The most frequently noted TEAEs from lacosamide were dizziness, sedation and diplopia, which all appeared to be dose-related. CONCLUSION: This post-marketing analysis suggests that lacosamide in clinical practice at least mirrors, and possibly outperforms the results seen in previous phase II/III trials.