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PubMed1982

Application of the multiple sleep latency test in disorders of excessive sleepiness.

Multiple sleep latency tests were performed in 42 drug-free outpatients with excessive sleepiness: 12 narcoleptics, 9 sleep apneics, 7 primary depressives, and 14 patients with miscellaneous disorders. Among-group comparisons were made by one-way ANOVA for each nap (time-of-day effect) and using four-nap means of EEG sleep variables. Four-nap means were significantly different among groups for percent awake, percent time spent asleep, stage 1 latency, and REM latency. Of 22 significant pairwise comparisons (P less than 0.05, LSD test), 77.3% occurred at 12.00 and 14.00. Depressives showed lower sleep percentage (more arousal) and fell asleep later than narcoleptics or apneics. Patients with miscellaneous disorders occupied a middle position. Sleep percentage was gradually reduced during the day in depressives but remained high or rose further in apneics, narcoleptics, and miscellaneous patients. Naps were SOREMP-positive (sleep onset REM) 60.4% of the time in narcoleptics, 25.0% in apneics, 3.5% in depressives, and 5.4% in miscellaneous patients. SOREMP distribution across naps (10.00, 12.00, 14.00 and 16.00) was 19%, 31%, 19% and 31%, respectively. REM latency was significantly shorter in narcolepsy than in apnea. In summary, results show a continuum of excessive daytime sleepiness (EDS), demonstrating MSLT application in the differential diagnosis of EDS and significant diurnal variation in sleep measures.

Circadian Rhythm↗

PubMed1995

Correlates of sleep latency on the multiple sleep latency test in a clinical population.

The multiple sleep latency test (MSLT) is commonly used as an objective measure of sleepiness. We retrospectively correlated MSLT scores from 147 patients with other information relating to sleepiness, namely demographic information, data from nocturnal polysomnograms (PSGs), and subjective assessments. The only variable that showed a valid and statistically significant correlation with the MSLT score was sleep latency on the PSG. The results were largely similar within subgroups focusing on (1) individuals with the ability to fall asleep on every nap, (2) subjects with abnormally short MSLT scores, (3) nap attempts that were successful, and (4) patients with particular diagnoses. We conclude that the mean sleep latency on the MSLT, in a clinical population, does not correlate well with a number of variables expected to influence sleepiness. While the validated utility of the MSLT in separating patients from normals or in identifying narcolepsy is not disputed, the accuracy of the MSLT as a measure of sleepiness appears to be limited.

Adult↗

PubMed1997

How should the multiple sleep latency test be analyzed?

Results of the multiple sleep latency test (MSLT) are commonly recorded as 4-5 latencies to sleep onset, together with their mean. The suitability of these and other MSLT measures of daytime sleep tendency was examined in 111 non-narcoleptic patients of a sleep disorders center. Sleep and breathing patterns had been recorded for one night, followed by a five-nap MSLT. It was found that MSLT latencies to sleep stages 1 and 2 were distributed non-normally. There was typically an excessive frequency of long latencies and a secondary peak at 20 minutes, the longest allowed latency. Wake efficiencies (WE) (100% time asleep) were similarly distributed. Mean sleep latencies (SL) and mean WE were generally distributed more normally than the corresponding medians. Regression analysis showed that the MSLT variables best predicted by sleep-disordered breathing during the previous night were those based on WE. Effects were greatest for the first 1-2 naps. Whether the 4- or 5-nap MSLT can be shortened will depend on corroborating data from other labs. For now, mean WE appears to be the best measure of daytime sleep tendency. Regardless of which MSLT measure is used, sleep-disordered breathing, nocturnal sleep time, age, and gender together explain less than one-fourth of the variance found in the non-narcoleptic patients of a sleep disorders center. Much daytime sleepiness therefore remains unexplained.

Adult↗

PubMed1985

Diagnosis of narcolepsy using the multiple sleep latency test: analysis of current laboratory criteria.

Multiple sleep latency tests (MSLT) performed on 144 patients with excessive daytime somnolence were examined for the diagnostic reliability of a short sleep latency (SL less than 5 min) and the presence of sleep-onset REM periods (SOREMPs). Based on clinical criteria, 61 patients (42%) were diagnosed as having narcolepsy. Thirty-five narcoleptic patients and five nonnarcoleptic patients exhibited a mean SL less than 5 min, yielding a sensitivity of 57% and a specificity of 94% for this criterion for pathological drowsiness. The occurrence of two or more SOREMPs was found in 52 narcoleptic patients but in only one nonnarcoleptic patient (sensitivity of 84% and specificity of 99%). Those narcoleptic patients with cataplexy demonstrated a shorter SL and more frequent SOREMPs than their noncataplectic counterparts. It was concluded that the MSLT is a highly reliable laboratory tool for the confirmation of the diagnosis of narcolepsy based on the SOREMP criterion. The criterion value for SL in pathological drowsiness may depend on laboratory conditions as well as the patient population selected.

Adolescent↗

PubMed2005

Oculomotor changes are associated to daytime sleepiness in the multiple sleep latency test.

Sleep onsets in the diurnal multiple sleep latency test (MSLT), following different sleep lengths of the preceding night sleep (8, 5, 4, 3, 2, 1 h) and following the corresponding recovery nights, were considered for a study on changes of oculomotor activity during sleep onset. The study aimed to assess the individual time course in spontaneous blinks (SBs) and slow eye movements (SEMs) during the sleep onset period and also the relationship with sleep latencies in the MSLT. Group analyses compared oculomotor changes between conditions characterized by a different level of daytime sleepiness. The results show a clear inverse relation between the two oculomotor measures, with a linear SB decrease and quadratic SEM increase across the wake-sleep transition. A 150 s sample of SB and SEM activity at the start of MSLT trials correlates with individual subsequent sleep latency. Finally, mean changes in daytime sleepiness as measured by the MSLT are paralleled by coherent oculomotor changes, with a significant linear decrease of SB as sleepiness increases as a consequence of previous sleep reduction. Both individual and group results show that endogenous blinking is associated with moderate changes in daytime sleepiness.

Adult↗

PubMed1995

What does the multiple sleep latency test measure in a community sample?

Multiple sleep latency test (MSLT)-defined daytime sleepiness and its relationships with nocturnal and daytime psychophysiological activation were investigated in a random community sample of 77 subjects aged 35-55 years. The correlation structure between all study variables was explained by a simple model of daytime sleepiness. The model suggested that indicators of psychophysiological arousal (psychological distress, nocturnal motor activity and serum thyrotropin level) and daytime reported tiredness, body mass index (BMI) and age were related significantly and independently to MSLT-defined daytime sleepiness. The arousal theory of insomnia and poor sleep in relation to MSLT behavior is discussed and the need of a multivariate approach is emphasized in MSLT studies.

Adult↗

PubMed1983

Elimination of multiple reactions of the Phadebact Streptococcus coagglutination test.

Strong multiple reactions often occur with the Phadebact Streptococcus test when the culture contains blood. These reactions interfere with the identification of the Lancefield groups of streptococci. Group B streptococci from the vagina of pregnant women are difficult to identify by slide coagglutination because of the frequent presence of blood on culture swabs. Elimination of these multiple reactions caused by blood would permit rapid identification of group B streptococci in pregnant women. Vaginal broth cultures were examined to determine the cause of multiple reactions with slide coagglutination and to eliminate them from the testing procedure. Of 245 maternal broth cultures, 135 (55%) yielded multiple reactions when tested by coagglutination. Such reactions were either eliminated or greatly diminished by heating the broth sample to 90 degrees C for 10 min. It was also found that globulins in the serum may be responsible for multiple reactions with blood. This heating protocol will permit vaginal broth cultures to be rapidly tested for group B streptococci by slide coagglutination.

Agglutination Tests↗

PubMed2004

On the logic of hypothesis testing in functional imaging.

Statistics is nowadays the customary language of functional imaging. It is common to express an experimental setting as a set of null hypotheses over complex models and to present results as maps of p-values derived from sophisticated probability distributions. However, the growing interest in the development of advanced statistical algorithms is not always paralleled by similar attention to how these techniques may regiment the ways in which users draw inferences from their data. This article investigates the logical bases of current statistical approaches in functional imaging and probes their suitability to inductive inference in neuroscience. The frequentist approach to statistical inference is reviewed with attention to its two main constituents: Fisherian "significance testing" and Neyman-Pearson "hypothesis testing". It is shown that these conceptual systems, which are similar in the univariate testing case, dissociate into two quite different methods of inference when applied to the multiple testing problem, the typical framework of functional imaging. This difference is explained with reference to specific issues, like small volume correction, which are most likely to generate confusion in the practitioner. Further insight into this problem is achieved by recasting the multiple comparison problem into a multivariate Bayesian formulation. This formulation introduces a new perspective where the inferential process is more clearly defined in two distinct steps. The first one, inductive in form, uses exploratory techniques to acquire preliminary notions on the spatial patterns and the signal and noise characteristics. The (smaller) set of likely spatial patterns generated is then tested with newer data and a more rigorous multiple hypothesis testing technique (deductive step).

Algorithms↗

PubMed2003

Verbal fluency assessment of patients with multiple sclerosis: test-retest and inter-observer reliability.

OBJECTIVE: To establish the reliability and validity of verbal fluency testing in patients with multiple sclerosis (MS). DESIGN: Each patient was assessed twice 7-14 days apart on a test of phonological fluency and again 7-14 days later when half of the patients were assessed for phonological fluency by a second assessor while the other half was assessed by the first assessor using a test of semantic fluency. SETTING: A specialist young disabled unit. SUBJECTS: Thirty-five patients with multiple sclerosis. MEASURES: Phonological fluency (PF) was tested giving the patient 60 seconds to generate words starting with 'F' 'A' and 'S'; semantic fluency (SF) with names of animals and fruits. Also used were the Short Orientation-Memory-Concentration Test and the Barthel ADL Index. RESULTS: On the first occasion 31/35 patients could be tested, and the average (SD) score of the PF was 21.9 (12.1), median 18. The test-retest reliability (n = 30/35) of the PF was good (Pearson r = 0.85). The score difference between the first two occasions ranged from +17 to -15 (median -3, mean -2.9, SD 6.7). The inter-observer reliability (n = 13/16) of the PF was good (Pearson r = 0.90). The difference of the score between the two assessors ranged from -9 to +6 (median 0, mean -1.2, SD 4.9). The correlation (Pearson) of the PF score with the SF, Barthel and SOMC was respectively r = 0.59, r = 0.27 and r = 0.63. CONCLUSIONS: Phonological fluency testing is reliable in people with MS.

Activities of Daily Living↗

PubMed1995

An analysis of the Adour-Swanson and House-Brackmann grading systems for facial nerve recovery.

Lack of uniformity in reporting facial nerve recovery in patients with facial nerve paralysis has been a major disadvantage in comparing treatment modalities. To remove subjectivity from the analysis, we devised a facial paralysis recovery profile as a system for measuring facial motion. This profile has been used since 1968 at Kaiser Permanente Medical Center, Oakland, California. The House facial paralysis grading system was introduced in 1983 for clinical use and was modified by Brackmann in 1985. This latter system has since been accepted by the American Academy of Otolaryngology-Head and Neck Surgery in the United States as the standard used in reporting results. In a prospective study of 54 patients, we tested multiple parameters that affect accurate reporting. We tested reliability and accuracy of facial measurements by using 30 control subjects and 3 independent examiners. We used Pearson correlation coefficients to statistically analyze results. To compare our system with the House-Brackmann grading system, we measured facial motions of 24 patients randomly selected from our data bank. All had incomplete returns of facial function and facial defects associated with faulty regeneration of a partially denervated facial nerve. Our overall results show defects in the House-Brackmann system which should be addressed. We offer the Adour-Swanson grading system as a reliable, easy-to-use, suitable alternative to the House-Brackmann system.

Face↗

PubMed2006

Duodenal EUS to identify thickening of the extrahepatic biliary tree wall in primary sclerosing cholangitis.

BACKGROUND: Diagnosing primary sclerosing cholangitis (PSC) is problematic and requires meeting a burden of proof through clinical, biochemical, radiologic, and histological features. Endoscopic ultrasound yields detailed images of the extrahepatic biliary tree, but its value in contributing to the diagnosis of this condition is unknown. OBJECTIVES: To determine the potential for transduodenal EUS to detect common bile duct wall thickening in PSC. DESIGN: A prospective, controlled study with retrospective, blinded data analysis. SETTING: Single tertiary referral center for inflammatory bowel disease and EUS. PATIENTS: Four groups of patients were assessed with radial endosonography: PSC (n = 9); inflammatory bowel disease (IBD) with abnormal liver blood tests (n = 21); choledocholithiasis (n = 15); and normal controls (n = 50). Measurements were made of the common bile duct diameter and wall thickness. INTERVENTIONS: Transduodenal radial EUS of the biliary tree. MAIN OUTCOME MEASUREMENTS: Common bile duct diameter and wall thickness. RESULTS: The mean diameter (SD) of the common bile duct for the PSC, IBD, choledocholithiasis, and normal control groups measured 8.9 mm (2.8), 5.4 mm (1.7), 7.2 mm (2.2), and 5.0 mm (1.9), respectively (PSC and choledocholithiasis groups compared to the IBD group, P < .05 for a single test of hypothesis, but correction for the multiple testing of data removed this significance; normal control group P < .005). Mean ductal wall thickness (SD) was 2.5 mm (0.8) for the PSC group, 0.7 mm (0.4) for the IBD group, 0.8 mm (0.4) for the choledocholithiasis group, and 0.8 mm (0.4) for the normal control group, respectively (PSC group compared to the other 3 groups, P < .005). LIMITATIONS: Assessment of intrahepatic PSC is problematic. CONCLUSION: Thickening (>1.5 mm) of the common bile duct wall is seen in patients with PSC but not in those with apparently uncomplicated IBD or choledocholithiasis. The results of this study suggest that standard endosonography contributes to the imaging and potentially to the diagnosis of PSC.

Adult↗

PubMed2006

Controlled trial of immediate endoluminal closure of colon perforations in a porcine model by use of a novel clip device (with videos).

BACKGROUND: Although endoluminal closure of a small perforation of the colon is technically feasible, the outcome of such a closure is unclear. OBJECTIVE: Our purpose was to evaluate the feasibility and the outcome of endoluminal closure of a small perforation of the colon with a novel clip device, the InScope MultiClip Applier (IMCA), and to assess the number of clips required for successful closure. DESIGN: Prospective controlled study. SETTING: University hospital. ANIMALS: 17 pigs. INTERVENTIONS: A 2-cm full-thickness colon perforation was randomized to 3 groups: control, no closure (n = 4), 2-clip closure (n = 7), and 4-clip closure (n = 6). MAIN OUTCOME MEASUREMENTS: (1) Technical feasibility of closure, (2) closure time, (3) clinical monitoring for 2 weeks, (4) necropsy (day 14), and (5) healing by a dye leak test and histologic examination. RESULTS: Endoscopic closure of the colon perforation was technically successful in 12 of 13 animals. A wide gaping hole prevented satisfactory closure in 1 animal. The median time for closure with 2 and 4 clips was 2 and 3 minutes, respectively. Clip closure of perforation prevented clinical sepsis (P = .008) and diminished the risk for fibrinous peritonitis (P = .02 for a single test of hypothesis; however, correction for the multiple testing of data removes this significance) and adhesion formation (P = .008) compared with controls, without any leakage. The outcomes of 2- and 4-clip closure were similar. CONCLUSIONS: Endoluminal closure of a 2-cm colon perforation with clips is successful in preventing peritonitis and adhesions and it can be accomplished quickly with this novel device. Clip closure at 1-cm intervals is sufficient for successful closure of a 2-cm colon perforation.

Animals↗

PubMed2000

The urine test strip of the future.

The aim of the classical multiple test strip is to perform routine chemical analysis in one single operation, yielding maximum diagnostic and prognostic information. A maximum of 10 test areas should not be exceeded. The efficiency of the currently marketed test strips is discussed and improvements within acceptable price limits are suggested.

Biomarkers↗

PubMed2004

Colonoscopy in patients 80 years of age and older is safe, with high success rate and diagnostic yield.

BACKGROUND: Colonoscopy is the standard investigation for colonic disease, but clinicians often are reluctant to refer elderly patients for colonoscopy because of a perception of higher risk and a high rate of incomplete examinations. METHODS: Data were prospectively collected on 924 consecutive colonoscopies performed over a 31-month period. Comparisons were made between two groups: patients 80 years of age or older (Group O) and patients less than 80 years of age (Group Y). Data were collected on sedation, crude and adjusted total colonoscopy rates, ileoscopy rate, anus to cecum time, total procedure time, diagnostic yield, and complications. Appropriate exclusions were made to calculate procedure success rates and time. RESULTS: Patients in Group O (n=110) received significantly less sedative medication compared with Group Y (n=814) (median dosage for midazolam, 1 mg vs. 2.5 mg; median dosage for meperidine, 12.5 vs. 25 mg; p < 0.0001). The adjusted total colonoscopy rate was 97% and 99.2% for Group O and Group Y (not significant), respectively. Ileoscopy rate was significantly lower in Group O (71.1% vs. 86.1%; p=0.0004). Median anus to cecum time was significantly longer in Group O (9.75 vs. 8.5 minutes; p=0.0182) in a single test of hypothesis; however, Bonferroni correction for multiple testing of data removes this significance. Median total procedure time also was longer in Group O (22 vs. 18.5 minutes; p=0.0001). Diagnostic yield was high, and the complication rate was low for both groups. Colorectal cancer was detected in 20% patients in Group O and 7.4% in Group Y (p < 0.0001). CONCLUSIONS: Colonoscopy in patients 80 or more years of age is safe, effective, and has a high diagnostic yield. Procedure times are slightly longer, and the ileoscopy rate is lower in this age group.

Adolescent↗

PubMed2005

Endoscopy or surgery for malignant GI outlet obstruction?

BACKGROUND: The treatment of gastroduodenal outflow obstruction (GOO) caused by malignant diseases represents a significant challenge. Open surgical gastrojejunostomy (GJ) has been the treatment of choice, but it has high morbidity and mortality rates. More recently, endoscopic placement of self-expanding metallic stents (SEMS) has been proposed and the results of small, preliminary studies are encouraging. This study compared technical and clinical success, morbidity, mortality, and hospital stay in patients undergoing endoscopic and surgical treatment of GOO. METHODS: Medical records of 60 consecutive patients with GOO seen between April 1997 and November 2002 were retrospectively reviewed. Because of extremely short life expectancy, 13 patients were treated by insertion of a double-lumen nasogastric-jejunal tube. The remaining 47 patients (28 men, 19 women; mean age 73.5 years, range 48-92 years) with unresectable pancreatic (33), gastric (7), metastatic lymph nodal (4), papillary (2), and biliary (1) tumors were treated by placement of a SEMS (24) or open surgical GJ (23). RESULTS: The technical success rates were similar, but clinical success was lower in the GJ group (92% vs. 56%, p = 0.0067). The SEMS group had a shorter length of hospital stay (3.0 [1.4] days vs. 24.1 [10.3], p < 0.001). Thirty-day mortality was 30% in the GJ group, and 0% in the SEMS group ( p = 0.004). Morbidity was higher in the GJ compared with the SEMS group (61% vs. 17%, p = 0.0021). Mean survival was longer in the SEMS group (96.1 [9.6] days vs. 70.2 [36.2] days, p = 0.0165 for a single test of hypothesis; Bonferroni correction for a multiple testing removes this significance), consequently, out-of-hospital survival was longer for the SEMS group (93.2 [9.3] days vs. 46.0 [31.5] days, p < 0.001). None of the endoscopic procedures required the assistance of an anesthesiologist or the use of an operating room. CONCLUSIONS: The results of this retrospective study suggest that SEMS insertion is better than surgical GJ for palliation of patients with GOO in terms of clinical success, morbidity, and mortality. Technical success rates were similar. SEMS placement should be proposed as the first-line treatment for relief of GOO. However, a randomized, comparative, prospective study of SEMS vs. laparoscopic GJ is needed.

Aged↗

PubMed2000

Decision analysis: dealing with uncertainty in diagnostic testing.

Decision analysis is a process for systematically analyzing complex choices by considering all pertinent information. In this paper, we discuss how uncertainty associated with diagnostic testing can be included in a decision analysis using pay-off tables and decision trees (decision-flow diagrams). Variables associated with diagnostic test interpretation (such as pre-test and post-test probability of disease; test sensitivity, specificity and predictive values; fixed cut-offs versus continuous measurement scales; test dependence associated with the use of multiple tests) are considered. Several decision criteria and output measures are discussed (including MAXIMIN and MAXIMAX criteria, opportunity costs, expected monetary values, expected utility, sensitivity and risk-profile analysis, and threshold analysis). The application of decision analysis to diagnostic testing for Johne's disease and traumatic reticuloperitonitis of cattle, and for canine heartworm disease are used to illustrate both population- and patient-oriented applications and criteria for ranking the desirability of different outcomes.

Animals↗

PubMed2000

Pediatric pulmonary function testing.

Pulmonary function testing is an essential component in the diagnosis and monitoring of the pediatric asthmatic. Very young children are capable of performing spirometry, lung Volumes, airway mechanics, and other testing. Obtaining valid test results in children is dependent on multiple factors including equipment selection, environment, technologist training and competence level, and the child's developmental age. Multiple test methods are discussed to assess the degree of airway obstruction and reversibility.

Adolescent↗

PubMed2000

Sensitivity, specificity and positive predictive value of patch testing: the more you test, the more you get? ESCD Working Party on Epidemiology.

Pathophysiological variability affects the results of patch testing. In addition, even a minimal degree of test-imprecision due to this variability has a number of important statistical consequences for the analysis and interpretation of any patch test data set. One such statistical phenomenon that is often overlooked is the dependence of the positive predictive value (i.e., the predictive value of a positive patch test) on sensitivity and specificity, the impact of which is heavily dependent on the proportion of truly allergic subjects that are studied. A 2nd important issue is the fact that patch testing is performed in series, which means multiple tests. If we assume, for example, a patch test series of only 10 allergens, then it can be demonstrated that there is a random probability of over 40%) to find, simply by chance, for at least 1 allergen, a statistically significant difference between 2 groups of patients. Comparison of the results of series between patients calls for statistical adjustments in order to prevent erroneously positive differences and/or associations.

Dermatitis, Allergic Contact↗