Increased electrode impedance as an indicator for early detection of deep brain stimulation (DBS) hardware Infection: Clinical experience and in vitro study.

BACKGROUND: When deep brain stimulation (DBS) infections are identified, they are often too advanced to treat without complete hardware removal. New objective markers to promptly identify DBS infections are needed. We present a patient with GPi (globus pallidus interna) DBS for dystonia, where the electrode impedance unexpectedly increased 3-months post-operatively, followed by serologic and hematologic markers of inflammation at 6-months, prompting explantation surgery. We recreated these conditions in a laboratory environment to analyze the pattern of changing of electrical impedance across the contacts of a DBS lead following Staphylococcus biofilm formation. METHODS: A stainless-steel culture chamber containing 1 % brain heart infusion agar was used. A DBS electrode was dipped in peptone water containing a strain of S. aureus and subsequently introduced into the chamber. The apparatus was incubated at 37 °C for 6 days. Impedance was measured at 24hr intervals. A control experiment without S. Aureus inoculation was used to determine changes in impedance over a period of 6-days. RESULTS: The mean monopolar impedance on day-1 was 751.8 ± 23.8 Ω and on day-3 was 1004.8 ± 68.7 Ω, a 33.7 % rise (p = 0.007). A faint biofilm formation could be seen around the DBS lead by day-2 and florid growth by day-3. After addition of the linezolid solution, a 15.9 % decrease in monopolar impedance was observed from day 3-6 (p = 0.003). CONCLUSION: This study gives insight into impedance trends following a hardware infection in DBS. Increased impedance outside expected norms may be valuable for early prediction of infection. Furthermore, timely management using antibiotics might reduce the frequency of infection-related explant surgeries.

Prevalence of ultrasonography proved polycystic ovaries in North Indian women with type 2 diabetes mellitus.

BACKGROUND: Polycystic ovaries (PCO) and their clinical expression (the polycystic ovary syndrome [PCOS]) as well as type 2 diabetes mellitus (T2DM) are common medical conditions linked through insulin resistance. We studied the prevalence of PCO and PCOS in women with diet and/or oral hypoglycemic treated T2DM and non-diabetic control women. DESIGN: Prospective study. METHODS: One hundred and five reproductive age group women with diet and /or oral hypoglycemic treated T2DM were the subjects of the study. Sixty age-matched non-diabetic women served as controls. Transabdominal ultrasonographic assessment of the ovaries was used to diagnose PCO. Clinical, biochemical and hormonal parameters were also noted. RESULTS: Ultrasonographic prevalence of PCO was higher in women with diabetes than in non-diabetic subjects (61.0% vs. 36.7%, P < 0.003) whereas that of PCOS was 37.1% in diabetic subjects and 25% in non-diabetic controls (P > 0.1). Diabetic women with PCO had diabetes of significantly longer duration than those without PCO (4.19+/-2.0 versus 2.9+/-1.6 yrs; p < 0.05). Among both diabetic and non-diabetic women, those with PCO had significantly higher plasma LH, LH/FSH ratio, total testosterone and androstenedione levels. CONCLUSION: This study demonstrates a higher prevalence of PCO in women with T2DM as compared to non-diabetic subjects.