A Literature Review of Methodologies Used in Randomized Clinical Trials of Agitation in Alzheimer's Disease

Agitation is a common and burdensome symptom associated with Alzheimer's disease (AD). This is a narrative literature review of the designs and methods used in randomized clinical trials of agitation in patients with AD; sources range from published, to completed but not published, to ongoing studies in the past 10 years. Selection for review included blinded, randomized trials conducted to assess the effect of a pharmacological intervention for which agitation in patients with AD was among the prespecified end points. Key criteria for exclusion included open-label studies, trials of dementia not specific to AD, or mixed populations of AD and unspecified dementia. A search of PubMed and clinicaltrials.gov databases identified 36 trials for which agitation was among the prespecified end points: 18 were published trials and 18 were completed but not published or ongoing. There was significant heterogeneity among AD studies in terms of diagnostic criteria, assessment of severity of disease and agitation, sample size and powering assumptions, treatment duration, patient age and cognitive status, and outcomes measurements. Few studies used a mitigation strategy for placebo response. Accumulating evidence suggests that it is important to consider the following in trial design: thresholds for baseline severity of agitation and AD; use of prespecified accepted criteria to define agitation; and use of standardized, validated tools to measure treatment effects during a trial. Adoption of these design strategies might help improve signal detection and bring us closer to identifying the most appropriate, effective, and safe treatments for agitation in patients with AD.

Effect of a balloon-expandable intracranial stent vs medical therapy on risk of stroke in patients with symptomatic intracranial stenosis: the VISSIT randomized clinical trial

IMPORTANCE

Intracranial stenosis is one of the most common etiologies of stroke. To our knowledge, no randomized clinical trials have compared balloon-expandable stent treatment with medical therapy in symptomatic intracranial arterial stenosis.

OBJECTIVE

To evaluate the efficacy and safety of the balloon-expandable stent plus medical therapy vs medical therapy alone in patients with symptomatic intracranial stenosis (≥70%).

DESIGN, SETTING, AND PATIENTS

VISSIT (the Vitesse Intracranial Stent Study for Ischemic Stroke Therapy) trial is an international, multicenter, 1:1 randomized, parallel group trial that enrolled patients from 27 sites (January 2009-June 2012) with last follow-up in May 2013.

INTERVENTIONS

Patients (N = 112) were randomized to receive balloon-expandable stent plus medical therapy (stent group; n = 59) or medical therapy alone (medical group; n = 53).

PRIMARY OUTCOME MEASURE

a composite of stroke in the same territory within 12 months of randomization or hard transient ischemic attack (TIA) in the same territory day 2 through month 12 postrandomization. A hard TIA was defined as a transient episode of neurological dysfunction caused by focal brain or retinal ischemia lasting at least 10 minutes but resolving within 24 hours. Primary safety measure: a composite of any stroke, death, or intracranial hemorrhage within 30 days of randomization and any hard TIA between days 2 and 30 of randomization. Disability was measured with the modified Rankin Scale and general health status with the EuroQol-5D, both through month 12.

RESULTS

Enrollment was halted by the sponsor after negative results from another trial prompted an early analysis of outcomes, which suggested futility after 112 patients of a planned sample size of 250 were enrolled. The 30-day primary safety end point occurred in more patients in the stent group (14/58; 24.1% [95% CI, 13.9%-37.2%]) vs the medical group (5/53; 9.4% [95% CI, 3.1%-20.7%]) (P = .05). Intracranial hemorrhage within 30 days occurred in more patients in the stent group (5/58; 8.6% [95% CI, 2.9%-19.0%]) vs none in the medical group (95% CI, 0%-5.5%) (P = .06). The 1-year primary outcome of stroke or hard TIA occurred in more patients in the stent group (21/58; 36.2% [95% CI, 24.0-49.9]) vs the medical group (8/53; 15.1% [95% CI, 6.7-27.6]) (P = .02). Worsening of baseline disability score (modified Rankin Scale) occurred in more patients in the stent group (14/58; 24.1% [95% CI, 13.9%-37.2%]) vs the medical group (6/53; 11.3% [95% CI, 4.3%-23.0%]) (P = .09).The EuroQol-5D showed no difference in any of the 5 dimensions between groups at 12-month follow-up.

CONCLUSIONS AND RELEVANCE

Among patients with symptomatic intracranial arterial stenosis, the use of a balloon-expandable stent compared with medical therapy resulted in an increased 12-month risk of added stroke or TIA in the same territory, and increased 30-day risk of any stroke or TIA. These findings do not support the use of a balloon-expandable stent for patients with symptomatic intracranial arterial stenosis.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00816166.

Comparative effectiveness of antibiotic-impregnated shunt catheters in the treatment of adult and pediatric hydrocephalus: analysis of 12,589 consecutive cases from 287 US hospital systems

OBJECT

The real-world effectiveness of antibiotic-impregnated shunt catheters to reduce the incidence of shunt infections is still debated. The literature to date consists mostly of small, single-institution studies. The aim of this study was to assess the incidence of infection for antibiotic-impregnated catheters (AICs) versus standard shunt catheters in a large nationwide administrative database.

METHODS

The authors retrospectively reviewed hospital discharge and billing records from the Premier Perspective Database from April 2003 to July 2009 to identify all adult and pediatric patients undergoing de novo ventricular shunt placement. The primary end point was the incidence of shunt infection within 1 year of implantation. Multivariate logistical regression was performed to determine factors associated with increased incidence of infection.

RESULTS

A total of 10,819 adult (AIC, 963; standard catheter, 9856) and 1770 pediatric (AIC, 229; standard catheter, 1541) patients underwent ventricular shunt placement in 287 US hospitals. Overall, the incidence of infection was 3.5% in adults (n=380) and 6.6% in pediatric patients (n=116). AICs were associated with significant reduction in infection for both adult (2.2% vs 3.6%, p=0.02) and pediatric (2.6% vs 7.1%, p<0.01) patients. AIC use was associated with reduced infection regardless of hospital size, annual shunt volume, hospital location, or patient risk factors and remained associated with a reduced infection in multivariate analysis for both adult (p=0.02) and pediatric (p=0.02) patients.

CONCLUSIONS

The use of antibiotic-impregnated shunt catheters was associated with a reduction in shunt infections for both adult and pediatric patients. This provides further support that AICs may represent a reliable means of reducing shunt infections for both adult and pediatric patients.

Cost savings associated with antibiotic-impregnated shunt catheters in the treatment of adult and pediatric hydrocephalus

BACKGROUND

Cerebrospinal fluid (CSF) shunt infection is a major cause of morbidity and mortality in the treatment of hydrocephalus and is associated with significant medical cost. Several studies have demonstrated the efficacy of antibiotic-impregnated (AI) shunt catheters in reducing CSF shunt infection; however, providers remain reluctant to adopt AI catheters into practice because of the increased upfront cost. The objective of this study was to determine if the use of AI catheters provided cost savings in a large nationwide database.

METHODS

Hospital discharge and billing records from the Premier Perspective Database from 2003-2009 were retrospectively reviewed to identify all adult and pediatric patients undergoing de novo ventricular shunt placement. The incidence of shunt infection within 1 year of implantation was determined. Shunt infection-related cost was defined as all inpatient billing costs incurred during hospitalization for treatment of shunt infection.

RESULTS

In 287 U.S. hospitals, 10,819 adult (AI catheters, 963; standard catheters, 9856) and 1770 pediatric (AI catheters, 229; standard catheters, 1541) patients underwent ventricular shunt placement. AI catheters were associated with significant reduction in infection for both adult (2.2% vs. 3.6%, P = 0.02) and pediatric (2.6% vs. 7.1%, P < 0.01) patients. Total infection-related costs were $17,371,320 ($45,714 ± $49,745 per shunt infection) for adult patients and $6,508,064 ($56,104 ± $65,746 per shunt infection) for pediatric patients. Infection-related cost per 100 de novo shunts placed was $120,534 for AI catheters and $162,659 for standard catheters in adult patients and $165,087 for AI catheters and $395,477 for standard catheters in pediatric patients.

CONCLUSIONS

In analysis of this large, nationwide database, AI catheters were found to be associated with a significant reduction in infection incidence, resulting in tremendous cost savings. AI catheters were associated with a cost savings of $42,125 and $230,390 per 100 de novo shunts placed in adult and pediatric patients, respectively.

Copy number variation plays an important role in clinical epilepsy

OBJECTIVE

To evaluate the role of copy number abnormalities detectable using chromosomal microarray (CMA) testing in patients with epilepsy at a tertiary care center.

METHODS

We identified patients with International Classification of Diseases, ninth revision (ICD-9) codes for epilepsy or seizures and clinical CMA testing performed between October 2006 and February 2011 at Boston Children's Hospital. We reviewed medical records and included patients who met criteria for epilepsy. We phenotypically characterized patients with epilepsy-associated abnormalities on CMA.

RESULTS

Of 973 patients who had CMA and ICD-9 codes for epilepsy or seizures, 805 patients satisfied criteria for epilepsy. We observed 437 copy number variants (CNVs) in 323 patients (1-4 per patient), including 185 (42%) deletions and 252 (58%) duplications. Forty (9%) were confirmed de novo, 186 (43%) were inherited, and parental data were unavailable for 211 (48%). Excluding full chromosome trisomies, CNV size ranged from 18kb to 142Mb, and 34% were >500kb. In at least 40 cases (5%), the epilepsy phenotype was explained by a CNV, including 29 patients with epilepsy-associated syndromes and 11 with likely disease-associated CNVs involving epilepsy genes or "hotspots." We observed numerous recurrent CNVs including 10 involving loss or gain of Xp22.31, a region described in patients with and without epilepsy.

INTERPRETATION

Copy number abnormalities play an important role in patients with epilepsy. Because the diagnostic yield of CMA for epilepsy patients is similar to the yield in autism spectrum disorders and in prenatal diagnosis, for which published guidelines recommend testing with CMA, we recommend the implementation of CMA in the evaluation of unexplained epilepsy.

Stroke treatment academic industry roundtable: research priorities in the assessment of neurothrombectomy devices

BACKGROUND AND PURPOSE

The goal of the Stroke Treatment Academic Industry Roundtable (STAIR) meetings is to advance the development of stroke therapies. At STAIR VIII, consensus recommendations were developed for clinical trial strategies to demonstrate the benefit of endovascular reperfusion therapies for acute ischemic stroke.

SUMMARY OF REVIEW

Prospects for success with forthcoming endovascular trials are robust, because new neurothrombectomy devices have superior reperfusion efficacy compared with earlier-generation interventions. Specific recommendations are provided for trial designs in 3 populations: (1) patients undergoing intravenous fibrinolysis, (2) early patients ineligible for or having failed intravenous fibrinolysis, and (3) wake-up and other late-presenting patients. Among intravenous fibrinolysis-eligible patients, key principles are that CT or MRI confirmation of target arterial occlusions should precede randomization; endovascular intervention should be pursued with the greatest rapidity possible; and combined intravenous and neurothrombectomy therapy is more promising than neurothrombectomy alone. Among patients ineligible for or having failed intravenous fibrinolysis, scientific equipoise was affirmed and the need to randomize all eligible patients emphasized. Vessel imaging to confirm occlusion is mandatory, and infarct core and penumbral imaging is desirable in later time windows. Additional STAIR VIII recommendations include approaches to test multiple devices in a single trial, utility weighting of disability end points, and adaptive designs to delineate time and tissue injury thresholds at which benefits from intervention no longer accrue.

CONCLUSIONS

Endovascular research priorities in acute ischemic stroke are to perform trials testing new, highly effective neuro thrombectomy devices rapidly deployed in patients confirmed to have target vessel occlusions.

Design of the Vitesse Intracranial Stent Study for Ischemic Therapy (VISSIT) trial in symptomatic intracranial stenosis

BACKGROUND

Patients with high-grade symptomatic intracranial stenosis (≥ 70%) have an increased risk of recurrent stroke despite medical treatment with antiplatelet or anticoagulant therapy. Intracranial stenting has been proposed as a viable treatment option for this high-risk patient population; however, evaluation of this therapy in randomized multicenter trials is needed. In this article, we present the design and methods of the Vitesse Intracranial Stent Study for Ischemic Therapy (VISSIT) trial for symptomatic intracranial stenosis.

METHODS

The VISSIT trial is a randomized control study designed to evaluate the safety, probable benefit, and effectiveness of the PHAROS Vitesse neurovascular balloon-expandable stent system plus medical therapy versus medical therapy alone in patients with cerebral or retinal ischemia due to neurovascular stenosis (≥ 70%) for preventing the primary composite end point: stroke in the same territory (distal to the target lesion) as the presenting event within 12 months of randomization or hard transient ischemic attack in the same territory (distal to the target lesion) as the presenting event from day 2 through month 12 postrandomization.

RESULTS

Enrollment began in February 2009 and was halted in January 2012 with 112 subjects enrolled into the study. Clinical follow-up will continue for the planned period of 12 months postrandomization.

CONCLUSIONS

The VISSIT trial may provide valuable insight into the use of balloon-expandable intracranial stent as a treatment option for high-risk patients. Lessons learned from this trial may better guide future clinical trial design on best patient selection, stenting techniques, and periprocedural management.

Comparison of Infection Rate With the Use of Antibiotic-Impregnated vs Standard Extraventricular Drainage Devices

BACKGROUND:

External ventricular drainage (EVD) catheters provide reliable and accurate means of monitoring intracranial pressure and alleviating elevated pressures via drainage of cerebrospinal fluid (CSF). CSF infections occur in approximately 9% of patients. Antibiotic-impregnated (AI) EVD catheters were developed with the goal of reducing the occurrence of EVD catheter-related CSF infections and their associated complications.

OBJECTIVE:

To present an international, prospective, randomized, open-label trial to evaluate infection incidence of AI vs standard EVD catheters.

METHODS:

Infection was defined as (1) proven infection, positive CSF culture and positive Gram stain or (2) suspected infection: (A) positive CSF culture with no organisms identified on initial Gram stain; (B) negative CSF culture with a gram-positive or -negative stain; (C) CSF leukocytosis with a white blood cell/red blood cell count &gt;0.02.

RESULTS:

Four hundred thirty-four patients underwent implantation of an EVD catheter. One hundred seventy-six patients in the AI-EVD cohort and 181 in the standard EVD catheter cohort were eligible for evaluation of infection. The 2 groups were similar in all clinical characteristics. Proven infection was documented in 9 (2.5%) patients (AI: 4 [2.3%] vs standard: 5 [2.8%], P = 1.0). Suspected infection was documented in 31 (17.6%) patients receiving AI and 37 (20.4%) patients receiving standard EVD catheters, P = .504. Duration of time to suspected infection was prolonged in the AI cohort (8.8 ± 6.1 days) compared with the standard EVD cohort (4.6 ± 4.2 days), P = .002.

CONCLUSION:

AI-EVD catheters were associated with an extremely low rate of catheter-related infections. AI catheters were not associated with risk reduction in EVD infection compared to standard catheters. Use of AI-EVD catheters is a safe option for a wide variety of patients requiring CSF drainage and monitoring, but the efficacy of AI-EVD catheters was not supported in this trial.

Cerebrospinal shunt infection in patients receiving antibiotic-impregnated versus standard shunts

OBJECT

Cerebrospinal fluid shunt infections are associated with significant morbidity and mortality in the treatment of adult and pediatric hydrocephalus. Antibiotic-impregnated shunt (AIS) catheters have been used with the aim of reducing shunt infection. While many studies have demonstrated a reduction in shunt infection with AIS, this reported efficacy has varied within the literature.

METHODS

The authors performed a systematic literature review to identify all published articles comparing the incidence of CSF shunt infection in AIS versus non-AIS catheters. The incidence of infection for AIS versus non-AIS catheters was calculated using the Mantel-Haenszel common odds ratio, and baseline demographics were compared between AIS and non-AIS cohorts.

RESULTS

Twelve AIS versus non-AIS cohort comparisons were identified in the literature (5 pediatric hydrocephalus, 3 adult hydrocephalus, and 4 mixed populations). In a total of 5613 reported shunt procedures (2664 AISs vs 2949 non-AISs), AISs were associated with a reduction in shunt infection (3.3% vs 7.2%; OR 0.439, p < 0.0001). In 787 shunt procedures for adult hydrocephalus (427 AIS vs 360 non-AIS), AISs were associated with reduction in shunt infection (0.9% vs 5.8%; OR 0.153, p < 0.0001). In 1649 shunt procedures for pediatric hydrocephalus (854 AIS vs 795 non-AIS), AISs were associated with reduction in shunt infection (5.0% vs 11.2%; OR 0.421, p < 0.0001).

CONCLUSIONS

The authors' systematic review of the literature demonstrates that AIS catheters are associated with a significant reduction over non-AIS catheters in the reported incidence of CSF shunt infection in adult and pediatric populations. The AIS catheters do not appear to be associated with an increased incidence of antibiotic-resistant microorganisms. Prospective, randomized trials are needed to firmly assess and confirm this apparent difference in infection incidence.

Point-of-service nerve conduction studies: an example of industry-driven disruptive innovation in health care

Nerve conduction studies (NCS) and needle electromyography are useful and established diagnostic procedures for evaluating patients with signs and symptoms of neuromuscular disease. Although technological advances have occurred since the introduction of commercial electromyography instrumentation in the 1950s, most improvements have been evolutionary and were designed to benefit traditional users--neurologists and physiatrists specializing in electromyography. In the past seven years, instruments have been introduced that automate NCS and thereby enable a broader group of physicians, including internists and orthopedic surgeons, to perform these studies and utilize electromyographic data in the care of their patients. Automated NCS devices are an example of what Clayton Christensen terms a "disruptive innovation." In this article, automated NCS is contrasted with traditional electromyography, and the challenges and opposition to its widespread adoption are explored.

Utility of nerve conduction studies for carpal tunnel syndrome by family medicine, primary care, and internal medicine physicians

INTRODUCTION

Nerve conduction studies (NCS) are increasingly being performed at the point-of-service by family medicine, primary care, and internal medicine (FM/PCP/IM) physicians. Carpal tunnel syndrome (CTS) is a common neuropathy often diagnosed with the aid of NCS.

METHODS

A retrospective analysis of a point-of-service NCS data registry was conducted; 1190 patients who underwent NCS by 613 FM/PCP/IM physician practices, for evaluation of CTS were analyzed. Utility measures included demographic and electrophysiological characteristics of study population, adherence to evidence-based testing guidelines, and relevance of diagnostic outcomes.

RESULTS

Tested patients tended to be over 40, female, and overweight or obese. The median nerve distal motor latency was 4.4 +/- 1.2 ms; 92.6% of studies met the testing guideline; 30.5% of tested limbs yielded normal results; 53.1% CTS; 5.4% ulnar neuropathy; and 11.0% nonspecific upper extremity neuropathy.

DISCUSSION

This study demonstrated that point-of-service NCS by FM/PCP/IM physicians for CTS was applied to appropriate patient subpopulations, was performed in accordance with evidence-based testing parameters, and generated relevant diagnostic outcomes.

Diabetic nerve conduction abnormalities in the primary care setting

BACKGROUND

Nerve conduction studies (NCS) are the most objective measure of nerve function, and their use is recommended in the clinical and epidemiological evaluation of diabetic polyneuropathy (DPN). The purpose of this study was to utilize automated NCS technology to characterize nerve conduction of patients with diabetes in primary care settings.

METHODS

The Diabetes cohort was drawn from 28 community clinics. The Control cohort consisted of subjects without diabetes and without evidence of neuropathy. Bilateral peroneal NCS were performed with an automated NCS instrument (NC-stat, NeuroMetrix, Inc., Waltham, MA). Neuropathic symptoms were quantified using an abbreviated form of the NTSS-6 questionnaire. Risk factors for abnormal NCS were determined using multivariate regression modeling.

RESULTS

Data were collected for 172 control subjects and 1,358 subjects with diabetes. Statistically significant differences in peroneal NCS were found. Of the Diabetes cohort, 75.1% had at least one NCS abnormality, and 53.2% had bilateral abnormalities. Of the asymptomatic patients, 45% had bilateral NCS abnormalities. By contrast, 40% of those with clinically significant symptoms lacked bilateral NCS abnormalities. Independent predictors for bilateral NCS abnormalities were age, height, weight, hemoglobin A1c (HbA1c), and duration of diabetes. Up to 16% of the variance in NCS measurements was explained by HbA1c, duration of diabetes, and several demographic variables.

CONCLUSIONS

This study suggests that automated NCS can provide nerve conduction confirmation of DPN in primary care settings and has clinical utility. These findings have important implications for the clinical and epidemiological evaluation of DPN.

Repeatability of nerve conduction measurements using automation

Objective

To quantify nerve conduction study (NCS) reproducibility utilizing an automated NCS system (NC-stat^®, NeuroMetrix, Inc.).

Method

Healthy volunteers without neuropathic symptoms participated in the study. Their median, ulnar, peroneal, and tibial nerves were tested twice (7 days apart) by the same technician with an NC-stat^® instrument. Pre-fabricated electrode arrays specific to each nerve were used. Both motor responses (compound motor action potential [CMAP] and F-waves –all nerves) and sensory responses (sensory nerve action potentials [SNAP] –median and ulnar nerves only) were recorded following supramaximal stimuli. Automated algorithms determined all NCS parameters: distal motor latency (DML), mean F-wave latency (FWL), distal sensory latency (DSL), CMAP amplitude, and SNAP amplitude. Latency was adjusted for skin temperature deviation from reference. Pearson correlation coefficient (CC), intraclass correlation coefficient (ICC), coefficient of variance (CoV), and relative intertrial variation (RIV) were calculated.

Results

Fifteen subjects participated in either upper or lower extremity studies with nine participating in both. With the exception of CMAP amplitude, all parameters had CoV less than 0.06. Upper extremity amplitude parameters had CCs greater than 0.85. CCs for latencies were greater than 0.80 except for the median nerve FWL (CC = 0.69). For lower extremity nerves, ICCs were highest for mean FWL (>0.90), followed by DML (>0.82) and then CMAP (peroneal 0.33, tibial 0.73). The 10th to 90th RIV percentiles were bounded by ±7% for F-wave latencies; ±9% for all DSLs; and ±11% for DML (except peroneal at 15%).

Conclusions

The reproducibility of NCS parameters obtained with an automated NCS instrument compared favorably with traditional electromyography laboratories. F-wave latencies had the highest repeatability, followed by DML, DSL, SNAP and CMAP amplitude. Given their high reproducibility, automated NCS instrument may encourage wider utilization of NCS in clinical and research applications.

Peroneal F-wave characteristics under submaximal stimulation

PURPOSE

F-wave studies are valuable tools in clinical neurophysiology. F-wave parameter estimation must be based on multiple F-wave traces due to their inherent variability. Repetitive supramaximal stimulation is uncomfortable for many patients. This study tested the hypothesis that submaximally stimulated nerves yield F-wave parameters equivalent to those obtained with supramaximal stimulation.

METHODS

Thirty-five peroneal nerves from 27 subjects were stimulated both supramaximally and submaximally. CMAP and F-wave responses from the extensor digitorum brevis muscle were recorded and analyzed offline. Automated algorithms were used to determine F-wave parameters.

RESULTS

Mean, minimum, maximum F-wave latencies, F-wave duration, and chronodispersion showed no statistically significant difference under the two stimulation conditions. F-wave persistence, amplitude, and subject's discomfort level, were lower with statistical significance. The correlation coefficient of submaximal and supramaximal mean F-wave latencies was 0.977 and their intraclass correlation coefficient was 0.976. The bias of the mean latencies was 0.21 ms and the 95% limits of agreement were less than 5% of the mean F-wave latency.

CONCLUSIONS

F-waves acquired with submaximal stimulation possess characteristics statistically equivalent to those obtained under supramaximal stimulation, as measured by the latency and duration parameters. Persistence and amplitude were lower. Reduction in discomfort level was also achieved.

Median and ulnar nerve conduction measurements in patients with symptoms of diabetic peripheral neuropathy using the NC-stat system

BACKGROUND

Diabetic peripheral neuropathy (DPN) is a common, disabling, and costly complication of diabetes mellitus. Although there are multiple methods for detecting and monitoring DPN, nerve conduction studies (NCS) are generally considered to be the most sensitive and reproducible. However, utilization of NCS in patients with diabetes is low, presumably because of limited access and economic issues. Advanced point-of-service NCS systems, already widely used in the assessment of entrapment neuropathies, may address these issues in the arena of diabetes.

METHODS

Seventeen patients with diabetes and clinical evidence of neuropathy were enrolled in the study. NCS were performed using the NC-stat nerve conduction testing system (NEUROMetrix, Inc., Waltham, MA) and compared against results from a neurologist-supervised study using a standard electromyography system, which was considered the reference method. Results for ulnar and median distal motor latencies (DMLs) and F-waves, obtained by both methods, were compared with each other. The NC-stat measurements were also compared with a historical control population.

RESULTS

A high correlation between the two methods of NCS assessment was demonstrated. The Pearson correlation coefficients between the NC-stat system and the reference measurements were 0.96 (DML) and 0.89 (F-wave latency) for the median nerve and 0.70 (DML) and 0.78 (F-wave latency) for the ulnar nerve. Significant differences were observed between the NC-stat and reference median (P < 0.001, paired t test) and ulnar (P < 0.05, paired t test) nerve DMLs. F-wave latencies did not demonstrate significant differences (P > 0.05, paired t test). The rate of abnormalities ranged from 17.7% for the median nerve DML to 26.7% for the ulnar nerve F-wave latency. The rate of upper extremity nerve involvement in DPN according to a case definition requiring both median and ulnar nerve abnormalities was 25.0%. The rate of median neuropathy at the wrist, which is the second most common neuropathy in individuals with diabetes, was 17.6%.

CONCLUSIONS

NC-stat-based NCS of the median and ulnar nerves provide results similar to those obtained with traditional neurologist-supervised NCS using a standard electromyography system. The number of subjects meeting electrophysiological criteria for DPN, affecting the upper extremities, is similar to prior studies. The widespread availability of the NC-stat system may provide a robust and objective method for identifying DPN and other neuropathies in patients with diabetes.

Time course and predictors of median nerve conduction after carpal tunnel release

PURPOSE

To identify predictors of outcome and of electrophysiologic recovery in patients with carpal tunnel syndrome (CTS) treated by endoscopic carpal tunnel release using a nerve conduction testing system (NC-Stat; NEUROMetrix, Inc, Waltham, MA).

METHODS

Validity of the automated nerve conduction testing system was shown by comparing presurgical distal motor latencies (DMLs) against a reference obtained by referral to an electromyography laboratory. The DML was evaluated in 48 patients with CTS. Measurements were obtained within 1 hour of surgery and at 2 weeks, 6 weeks, 3 months, and 6 months after carpal tunnel release. Presurgical and postsurgical DMLs were then compared and correlated with variables and possible predictors of outcome including age, body mass index, gender, and presurgical DMLs.

RESULTS

The automated nerve conduction testing system DMLs matched those of reference electromyography/nerve conduction study values with high correlation. Sensitivity of the automated nerve conduction testing system when compared with a standardized CTS case definition was 89%, with a specificity of 95%. A significant correlation was found between the DML before release and the DML 1 hour after release. Moreover, maximal postsurgical DML improvement was highly dependent on the presurgical DML, with no improvement shown for the <4-ms group, mild improvement for the 4-to-6-ms group, and maximal improvement in the >6-ms group. Among the clinical variables of age, gender, and body mass index only age was mildly predictive of postrelease DML changes at 6 months. No other correlations between clinical variables and postsurgical DMLs were significant. In addition the predictive value of age was lost when combined with the presurgical DML in a multivariate analysis.

CONCLUSIONS

Postsurgical changes in the median nerve DML were highly dependent on the prerelease latency. The sensitivity and specificity of a nerve conduction monitoring system in detecting and aiding in the diagnosis of CTS is useful in the long-term management of patients with CTS and can aid in determining the level of improvement in median nerve function after endoscopic carpal tunnel release.

Homocystinuria presenting as psychosis in an adolescent

Homocystinuria usually presents with ectopia lentis, mental retardation, thromboembolic complications, and skeletal abnormalities. Whereas neuropsychiatric abnormalities are often recognized in untreated homocystinuria, initial presentation with acute psychosis has only rarely been reported. We describe a previously well 17-year-old adolescent with an acute psychosis characterized by auditory and visual hallucinations and marked paranoia who was found to have pyridoxine-responsive homocystinuria. His mental state normalized within several weeks of inception of pyridoxine and antipsychotic therapy. Pyridoxine-responsive homocystinuria is commonly missed on neonatal screens and should be recognized as a potentially treatable cause of acute psychosis in childhood and adolescence.

Enteral nutrition and corticosteroids in the treatment of acute Crohn's disease in children

BACKGROUND

The optimal treatment of acute Crohn's disease in children remains controversial. In adults, steroid therapy has been shown to be superior to exclusive enteral nutrition. However, enteral nutrition is effective at inducing a remission in many children with acute Crohn's disease. Steroid usage in children has been associated with adverse side effects, particularly with delayed growth and pubertal development.

METHODS

Randomized clinical trials comparing exclusive enteral nutrition with corticosteroids were identified. Two independent reviewers extracted data from selected studies. Studies were assessed for heterogeneity and relative risks for remission induction with enteral nutrition were obtained. Sensitivity analyses were performed in partially randomized studies. Estimates were made of the number of studies needed to overturn the current result. Other outcome measures were qualitatively assessed.

RESULTS

In five randomized clinical trials comprising 147 patients, enteral nutrition was as effective as corticosteroids at inducing a remission (RR = 0.95 [95% confidence interval 0.67, 1.34]). Addition of two further nonrandomized trials did not significantly alter the result. A minimum of 10 further studies, equal in size and outcome to the largest reported pediatric trial to date (n = 68, RR = 0.84), would be required to demonstrate a significant benefit of steroid therapy over enteral nutrition.

CONCLUSIONS

There is no difference in efficacy between enteral nutrition and corticosteroid therapy in the treatment of acute Crohn's disease in children. Improved growth and development, without the side effects of steroid therapy, make enteral nutrition a better choice for first-line therapy in children with active Crohn's disease.