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At least 109 records · Page 6Linked to original sources

PubMed2000

The role of mediators in memory retrieval as a function of practice: controlled mediation to direct access.

The role of prior knowledge in retrieval of Spanish-English vocabulary pairs learned using keyword mediators was examined in 4 experiments. Retrieval was tested immediately after learning and after 1-week and 1-month no-practice intervals (Experiment 1), after moderate retrieval practice (Experiment 2), and after extended retrieval practice (Experiments 3 and 4). Using accuracy, latency, and verbal report data, a detailed account of memory retrieval processes was developed. Initial retrieval is an explicit mediation process that involves retrieving keyword mediators into working memory and using them as retrieval cues to access the English equivalents of the Spanish words. After extended vocabulary retrieval practice, this sequential mediation process qualitatively changed to a direct retrieval process in which the English equivalent was accessed in a single working memory step. However, direct retrieval was still influenced by a covert mediation process.

Adult↗

PubMed2001

Selective activation of the ventrolateral prefrontal cortex in the human brain during active retrieval processing.

The present study examined the role of the prefrontal cortex in retrieval processing using functional magnetic resonance imaging in human subjects. Ten healthy subjects were scanned while they performed a task that required retrieval of specific aspects of visual information. In order to examine brain activity specifically associated with retrieval, we designed a task that had retrieval and control conditions that were perfectly matched in terms of depth of encoding, decision making and postretrieval monitoring and differed only in terms of whether retrieval was required. In the retrieval condition, based on an instructional cue, the subjects had to retrieve either the particular stimulus that was previously presented or its location. In the control condition, the cue did not instruct retrieval but shared with the instructional cues the function of alerting the subjects of the impending test phase. The comparison of activity between the retrieval and control conditions demonstrated a significant and selective increase in activity related to retrieval processes within the ventrolateral prefrontal cortical region, more specifically within area 47/12. These activity increases were bilateral but stronger in the right hemisphere. The present study by strictly controlling the level of encoding, postretrieval monitoring, and decision making has demonstrated a specific increase in the ventrolateral prefrontal region that could be clearly related to active retrieval processing, i.e. the active selection of particular stored visual representations.

Adult↗

PubMed2002

Surgical sperm retrieval after previous vasectomy and failed reversal: clinical implications for in vitro fertilization.

OBJECTIVE: To investigate the effect of the interval between previous vasectomy reversal on retrieval rates of epididymal and testicular spermatozoa using percutaneous epididymal sperm aspiration (PESA), or testicular sperm extraction (TESE), and the subsequent reproductive potential of these gametes in intracytoplasmic sperm injection (ICSI) cycles. PATIENTS AND METHODS: Sixty-six consecutive sperm retrievals were considered in patients who were azoospermic after previous vasectomy, of whom 54 had had a previous failed reversal, the remainder deciding against a reversal. PESA and TESE retrieval rates were noted, as were the time since vasectomy and the interval between vasectomy and unsuccessful reversal. The presence of palpable epididymal cysts was noted, with their effect on sperm retrieval rates. Fertilization and pregnancy rates were analysed in subsequent ICSI cycles using freshly retrieved spermatozoa or frozen-thawed cryopreserved spermatozoa. RESULTS: All 66 patients had sperm retrieved successfully; the success rates for PESA were not significantly affected by previous failed reversal when compared with patients who had not had a reversal, at 14 of 54 (26%) vs five of 12 (P=0.3). The interval since vasectomy did not affect PESA retrieval rates but there was a significantly poorer retrieval rate for PESA in the presence of palpable epididymal cysts, at seven of 35 (20%) vs 12 of 23 (52%) (P=0.012). Fertilization rates were significantly lower using cryopreserved spermatozoa retrieved from either the epididymis or testis (50% vs 70%, P=0.007), although subsequent implantation and pregnancy rates were not significantly different. CONCLUSION: Surgical sperm retrieval is successful in all cases of azoospermia secondary to vasectomy, either by PESA or TESE. There are no clinical markers to indicate which patients will have successful PESA after vasectomy, although the presence of epididymal cysts is associated with significantly lower retrieval rates. The reduction in fertilising ability of cryopreserved spermatozoa does not affect clinical pregnancy rates in ICSI cycles.

Adult↗

PubMed1995

Retrieval of inedible objects by Norway rats after habituation of gnawing: resistance to satiation?

Retrieval of wooden blocks by Norway rats was tested after continuous exposure to these objects sufficient to reduce gnawing. In two experiments rats were first allowed to retrieve during restricted daily trials. Then they were exposed to blocks in their home cages, and at some point during exposure they were retested in the retrieval situation. In Experiment 1, further retrieval tests were given beginning the day after blocks were introduced in the cages. In Experiment 2, rats were exposed to blocks for 100 days before they were retested for retrieval. In both experiments, amount of retrieval was minimally affected by exposure, although gnawing was significantly depressed. This contrasts with earlier work, which showed that habituation of gnawing in the cage was followed by a significant decline in retrieval. The major qualitative difference between this and past work was that rats in the present experiments were allowed to retrieve the blocks before continuous exposure to them. The author concluded that retrieval experience may lead to persistence of retrieval despite a decline in incentive value of the objects retrieved, indicated by the decline in gnawing, and he discusses relations to other demonstrations of persistence in the absence of original motivational conditions-in particular, "resistance to satiation" effects.

Animals↗

PubMed2002

A modified reduced-temperature antigen retrieval protocol effective for use with a polyclonal antibody to cyclooxygenase-2 (PG 27).

Antigen retrieval is now a standard procedure in immunohistochemical studies of tissues for diagnosis and research. While the most commonly used protocol (20 minutes at 100 degrees C in citrate buffer pH 6.0) is effective for many antibody/antigen combinations, experience has shown that in some instances, this standard approach fails. Under these circumstances, a successful antigen retrieval protocol may still be established by varying key conditions in the antigen retrieval process. The authors previously have advocated a test battery approach to determine the optimal conditions for antigen retrieval, illustrated here with respect to a polyclonal antibody to cyclooxygenase-2 (PG-27) that failed to give a positive staining result after orthodox antigen retrieval. The key feature of this modified antigen retrieval protocol is heating the deparaffinized tissue sections at a reduced temperature (90 degrees C as opposed to 100 degrees C). For this particular antibody, a boiling condition yields a negative result, a principal reason why previous investigators have used a tyramide signal amplification system to achieve satisfactory immunohistochemical results with this antibody. The optimal antigen retrieval protocol established in the authors' laboratory for this polyclonal antibody to cyclooxygenase-2 (PG-27) was evaluated in a study of formalin-fixed, paraffin-embedded cell lines and 31 bladder cancer tissue blocks using the tissue microarray technique, with side-by-side comparison between the results obtained by a tyramide signal amplification method (without antigen retrieval) and a standard immunohistochemical method with the optimized antigen retrieval protocol. The reduced temperature antigen retrieval protocol yielded a comparable or superior immunostaining for cyclooxygenase-2 both in cell lines and tissue blocks. In conclusion, use of the test battery approach allowed development of a modified antigen retrieval technique that provides a more reliable, much simpler approach for the demonstration of cyclooxygenase-2 in archival tissues.

Antibodies↗

PubMed2005

The Jonas study: evaluation of the retrievability of the Cordis OptEase inferior vena cava filter.

PURPOSE: To evaluate the success, safety, and efficacy of the retrieval of the OptEase Permanent/Retrievable Vena Cava Filter (Cordis, Warren, NJ), when implanted for temporary protection against venous thromboembolism. MATERIALS AND METHODS: This prospective, multicenter, non-randomized study enrolled 27 patients who needed temporary protection against pulmonary embolism in whom the intent at the time of filter insertion was retrieval of the OptEase filter. Patients presented with deep venous thrombosis (n = 17), pulmonary embolism (PE) (n = 6), and high risk for PE without thromboembolic disease (n = 4). Assessments included duplex sonography of the access site performed within 24 hours of device implantation and retrieval. All patients underwent cavography before and after filter placement and filter retrieval. Contrast-enhanced computed tomography (CT) of the abdomen and clinical follow-up was performed at 1 month after device retrieval. RESULTS: Of the 27 enrolled patients, 21 patients (77.8%) met the criteria for retrieval and all 21 patients (100%) had filters successfully retrieved with no associated adverse events. Retrieval was not attempted in six patients as a result of ongoing contraindication to anticoagulation (n = 3), large trapped thrombi within the filter (n = 2), and poor patient prognosis (n = 1). Time to retrieval ranged from 5 to 14 days with a mean implantation time of 11.1 days +/- 1.82. No symptomatic pulmonary embolism, vena cava wall injury, vena cava stenosis, significant bleeding, filter fracture, or filter migration was observed. Nineteen of the 21 patients (90.5%) were followed for 1-month post-retrieval with no device-related adverse events or symptomatic PE. Caval patency was documented in 18 of these 19 patients with CT. Two patients were lost to follow-up, and one patient refused to undergo CT examination. CONCLUSION: The OptEase permanent/retrievable vena cava filter can be safely and successfully retrieved up to 14 days in patients who no longer require inferior vena cava filter protection against pulmonary embolism.

Adult↗

PubMed1999

Frontal brain activity during episodic and semantic retrieval: insights from event-related potentials.

Previous neuropsychological and neuroimaging results have implicated the prefrontal cortex in memory retrieval, although its precise role is unclear. In the present study, we examined patterns of brain electrical activity during retrieval of episodic and semantic memories. In the episodic retrieval task, participants retrieved autobiographical memories in response to event cues. In the semantic retrieval task, participants generated exemplars in response to category cues. Novel sounds presented intermittently during memory retrieval elicited a series of brain potentials including one identifiable as the P3a potential. Based on prior research linking P3a with novelty detection and with the frontal lobes, we predicted that P3a would be reduced to the extent that novelty detection and memory retrieval interfere with each other. Results during episodic and semantic retrieval tasks were compared to results during a task in which subjects attended to the auditory stimuli. P3a amplitudes were reduced during episodic retrieval, particularly at right lateral frontal scalp locations. A similar but less lateralized pattern of frontal P3a reduction was observed during semantic retrieval. These findings support the notion that the right prefrontal cortex is engaged in the service of memory retrieval, particularly for episodic memories.

Adolescent↗

PubMed2002

Comparing techniques for estimating automatic retrieval: effects of retention interval.

Results from implicit memory (IM) tasks suggest that automatic retrieval remains stable or decreases over time. In contrast, results from the process dissociation approach (PDA) suggest that automatic retrieval may actually increase over time. One explanation for these discrepant results is that performance on IM tasks is contaminated by controlled retrieval strategies, thereby overestimating automatic retrieval, particularly at short retention intervals, when controlled retrieval strategies are high. An alternative explanation is that automatic and controlled retrieval are positively correlated, rather than independent as assumed by the PDA. If so, the PDA would underestimate automatic retrieval, particularly when controlled retrieval strategies are high. Results from a speeded IM task suggest that a standard IM task provided an accurate estimate of automatic retrieval, whereas the PDA underestimated automatic retrieval at a short retention interval. This pattern of underestimation by the PDA supports the conclusion that automatic and controlled retrieval were positively correlated rather than independent.

Automatism↗

PubMed2001

A randomized controlled trial of the accuracy of clinical record retrieval using SNOMED-RT as compared with ICD9-CM.

BACKGROUND: Concept-based Indexing is purported to provide more granular data representation for clinical records.1,2 This implies that a detailed clinical terminology should be able to provide improved access to clinical records. To date there is no data to show that a clinical reference terminology is superior to a precoordinated terminology in its ability to provide access to the clinical record. Today, ICD9-CM is the most commonly used method of retrieving clinical records. OBJECTIVE: In this study, we compare the sensitivity, specificity, positive likelihood ratio, positive predictive value and accuracy of SNOMED-RT vs. ICD9-CM in retrieving ten diagnoses from a random sample of 2,022 episodes of care. METHOD: We randomly selected 1,014 episodes of care from the inpatient setting and 1,008 episodes of care from the outpatient setting. Each record had associated with it, the free text final diagnoses from the Master Sheet Index at the Mayo Clinic and the ICD9-CM codes used to bill for the encounters within the episode of care. The free text diagnoses were coded by two expert indexers (disagreements were addressed by a Staff Clinician) as to whether queries regarding one of 5 common or 5 uncommon diagnoses should return this encounter. The free text entries were automatically coded using the Mayo Vocabulary Processor. Each of the ten diagnoses was exploded in both SNOMED-RT and ICD9-CM and using these entry points, a retrieval set was generated from the underlying corpus of records. Each retrieval set was compared with the Gold Standard created by the expert indexers. RESULTS: SNOMED-RT produced significantly greater specificity in its retrieval sets (99.8% vs. 98.3%, p<0.001 McNemar Test). The positive likelihood ratios were significantly better for SNOMED-RT retrieval sets (264.9 vs. 33.8, p<0.001 McNemar Test). The positive predictive value of a SNOMED-RT retrieval was also significantly better than ICD9-CM (92.9% vs. 62.4%, p<0.001 McNemar Test). The accuracy defined as 1 (the total error rate (FP+FN) / Total # episodes queried (20,220)) was significantly greater for SNOMED-RT (98.2% vs. 96.8%, p=0.002 McNemar Test). Interestingly, the sensitivity of the SNOMED-RT generated retrieval set was not significantly different from ICD9-CM, but there was a trend toward significance (60.4% vs. 57.6%, p=0.067 McNemar Test). However, if we examine only the outpatient practice SNOMED-RT produced a more sensitive retrieval set than ICD9-CM (54.8% vs. 46.4%, p=0.002 McNemar Test). CONCLUSIONS: Our data clearly shows that information regarding both common and rare disorders is more accurately identified with automated SNOMED-RT indexing using the Mayo Vocabulary Processor than it is with traditional hand picked constellations of codes using ICD9-CM. SNOMED-RT provided more sensitive retrievals of outpatient episodes of care than ICD9-CM.

Decision Support Systems, Management↗

PubMed1998

Dimensional characteristics of uncomplicated autopsy-retrieved acetabular polyethylene liners by ultrasound.

A new, in vitro ultrasound-based method to measure the thickness of acetabular polyethylene components was developed and applied to 26 uncomplicated autopsy retrieved components and 40 unused components. The average age at total hip arthroplasty was 62 years and the average time in service of the retrieved components was 49 months. The clinical notes indicated that each of the arthroplasties was functioning well at the time of the patients death. Thickness distributions in the retrieved components had two distinct patterns. Eighteen of the retrieved components (69%) had their thinnest areas self-contained and located near the polar point. In the other 8 retrieved components (31%) the areas of minimum thickness were adjacent to the rim. Thickness distribution in the unused cups was predominately concentric with the thinnest area located near the polar point (85% of the cups). Detection limits for dimensional change were established based on the variability found in the unused liners. Fifteen of the 26 retrieved components (58%) had areas of reduced thickness which exceeded the detection limits; the average thickness reduction rate for these components was 0.076 mm per year. The other 11 retrieved components (42%) lacked such areas. The 15 cups with areas of reduced thickness had a longer time in service (63 +/- 18 months) than the 11 cups without areas of reduced thickness (32 +/- 25 months) (p = 0.003), but no other clinical factor (age, gender, Harris hip score, size and inclination of the cup, type of femoral fixation) was associated with these 15 cups. Cylindrical models to estimate volumetric change tended to underestimate the actual changes, suggesting that the actual particulate burden may be greater than previously appreciated. Finding that the pattern of thickness reduction can vary suggests that distinctive hip loading modes may be present postoperatively in patients with total hip arthroplasty. The wear rates of these components are consistent with wear rates calculated from radiographic data for well-functioning implants and are considerably lower than wear rates calculated for surgically-retrieved implants, indicating that autopsy-derived retrievals may be more representative of the majority of components currently in service than surgically-derived retrievals.

Aged↗

PubMed1996

Induction of a memory retrieval strategy by young children.

This study examines children's modification of their own retrieval processes in a cued recall task. Each experiment had multiple study-test trails with triplets of categorically related words (Horse-Pig-Cow). Category-orienting questions were asked at acquisition, and each trial had different triplet stimuli. The last triplet word was the target, and the retrieval cues were the whole-context cue (Horse-Pig), a part context cue (Horse), or a noncontext associate (Goat). The measure of retrieval induction was recall increases across trials. Experiments 1 and 3 examined retrieval support for induction by 7- to 12-year olds by manipulating cue type. Experiments 2 and 4 manipulated acquisition variables that might effect retrieval induction. The results showed induction of an effective retrieval strategy in the situations of maximum retrieval support even by the 7-year olds, and developmental differences occurred in the situations where the retrieval cues provided few hints about the acquisition encoding operation. The results suggest that monitoring and modification of retrieval processes should be distinguished and that monitoring is necessary but not sufficient for induction of an effective retrieval strategy. The results have implications for understanding children's strategy-utilization deficiencies in memory tasks.

Attention↗

PubMed2001

Animal experience in the Günther Tulip retrievable inferior vena cava filter.

PURPOSE: To assess the retrievability of the Günther Tulip temporary inferior vena cava filter from a technical viewpoint, and consider the histopathologic changes that occur at the anchoring site of the filter prongs to the vein endothelium in Landrace pigs. METHODS: Twenty-two Günther Tulip retrievable filters were inserted in 22 experimental Landrace pigs via the jugular vein. Device implantation time was 0, 3, 7, 12, 14, 15, 16, 20, 30, 35 and 56 days. Study subjects were divided into two groups. In one group the filter was retrieved percutaneously via the jugular vein whereas in the other group it was removed surgically. The specimens obtained (vena cava and filter) were histopathologically examined. Prior to filter retrieval, a venacavography was obtained in all cases. Degree of retrieval difficulty was rated as follows: no difficulty (N), slight (S), mild (M), high (H) and unretrievable (U). RESULTS: Of the 22 implanted filters, 11 should have been removed percutaneously but this was impossible in three cases (U). In four cases the device was retrieved with no difficulty (N); in two cases the degree of difficulty was mild (M) and in other two it was high (H) and slight (S) respectively. Retrieval difficulties were observed after 16 days. Starting from day 20, there was evidence of fibrosis with thick intimal proliferation and total filter prong involvement, which accounts for the difficulty in retrieving the device. CONCLUSIONS: It is advisable not to exceed a filter retrieval time of 16 days in view of the fibrotic changes reported. It might be necessary to perform a larger study with more animals and with retrieval times between 14 and 20 days.

Animals↗

PubMed2006

Modulation of the electrophysiological correlates of retrieval cue processing by the specificity of task demands.

Retrieval orientation refers to the differential processing of retrieval cues according to the type of information sought from memory (e.g., words vs. pictures). In the present study, event-related potentials (ERPs) were employed to investigate whether the neural correlates of differential retrieval orientations are sensitive to the specificity of the retrieval demands of the test task. In separate study-test phases, subjects encoded lists of intermixed words and pictures, and then undertook one of two retrieval tests, in both of which the retrieval cues were exclusively words. In the recognition test, subjects performed 'old/new' discriminations on the test items, and old items corresponded to only one class of studied material (words or pictures). In the exclusion test, old items corresponded to both classes of study material, and subjects were required to respond 'old' only to test items corresponding to a designated class of material. Thus, demands for retrieval specificity were greater in the exclusion test than during recognition. ERPs elicited by correctly classified new items in the two types of test were contrasted according to whether words or pictures were the sought-for material. Material-dependent ERP effects were evident in both tests, but the effects onset earlier and offset later in the exclusion test. The findings suggest that differential processing of retrieval cues, and hence the adoption of differential retrieval orientations, varies according to the specificity of the retrieval goal.

Adolescent↗

PubMed2006

Brain and behavioral indices of retrieval mode.

In recent event-related potential (ERP) studies of episodic retrieval, ERPs have been acquired in tasks where participants have been cued trial-by-trial to prepare either to make episodic or semantic retrieval judgments. ERPs elicited during this preparatory cue period and separated according to retrieval task have diverged at right frontal scalp electrodes, with a relatively greater positivity associated with preparation for episodic rather than for semantic retrieval. Importantly, this pattern of differences has been observed only on 'stay' trials: those trials where the participant was cued to prepare for the same retrieval task on the previous trial. These findings have provided the basis for the proposal that the ERP modulations index processes that support the adoption or configuration of retrieval mode - a tonic process that can be sustained while recovery of episodic information is required and which facilitates the retrieval process. In these studies, however, the preparatory period on each trial was no more than 2000 ms, raising the possibility that, with more time available, neural correlates of these preparatory processes would not be restricted to stay trials. In this experiment, participants were cued trial-by-trial to complete either an episodic or a semantic retrieval task, and the preparatory period was greater than 4000 ms on the majority of trials. In keeping with previous findings, the ERPs elicited by these two cue types diverged principally on stay trials at right frontal electrode locations, suggesting that time to prepare is not the primary determinant of the onset of task-specific preparatory retrieval processing. In an important addition to previous findings, moreover, the accuracy of episodic memory judgments increased with the number of successive trials of the same task that participants completed, a finding consistent with the view that adopting a retrieval mode successfully can influence the accuracy of episodic memory judgments.

Adolescent↗

PubMed1997

Device choice and experience level in endoscopic foreign object retrieval: an in vivo study.

BACKGROUND: Successful foreign object retrieval may depend on device choice and the experience level of the endoscopist, although these factors have not been systematically evaluated. METHODS: In anesthetized pigs, the ability to retrieve foreign objects (metal tack, button disc battery, wooden toothpick) placed endoscopically into the stomach was assessed. Seven university medical center gastroenterology attending physicians (5 clinical and 2 basic science research [BSR]), and 4 fellows-in-training participated. The devices used were the Roth retrieval net, rat tooth forceps, Dormia basket, polypectomy snare, and radial jaw forceps. The time to retrieve each object into an esophageal overtube within a 5 minute maximum was measured. RESULTS: Only the Roth net and Dormia basket were successful in retrieving the button disc battery, although the Roth net was superior (100% vs 27%, Fisher p < 0.025). All devices were equally successful at retrieving the tack (82% to 100%, p = NS). The snare was significantly faster than the Roth net (p < 0.05). For the tack, there was significantly fewer difficulties encountered with the snare than the Roth net (Fisher p < 0.03). The Roth net was incapable of retrieving the toothpick; the other devices were equally successful (91% to 100%). The clinical attendings had a significantly higher success rate (95%) than the fellows (82%, chi squared p < 0.05) or combined fellows/BSR attendings (80%, p < 0.02), and were significantly faster than the fellows (p < 0.0002) or the fellows/BSR attendings (p < 0.0003). CONCLUSIONS: The Roth net is the best device for retrieving smooth objects such as the button disc battery. For sharp objects, such as the tack and toothpick, best results were achieved with the snare, although the forceps were also effective. More experienced endoscopists had higher success rates and faster retrieval times. Both device choice and the experience level of the endoscopists have an impact on successful foreign object retrieval.

Animals↗

PubMed1990

Ten years of training community urologists and general surgeons to do cadaver kidney retrievals.

We trained 82 community hospital cadaver kidney retrieval teams during a 10-year period ending June 30, 1987. During the last 5 years of that period the concept of multiple organ retrieval was introduced into the training sessions and 429 cadaver kidney grafts were retrieved. Of those kidneys 292 were transplanted at our hospital, and the function of 220 cadaver kidney grafts retrieved by the community hospital teams was compared to that of 72 retrieved by the transplant center retrieval team. Of the cadaver kidney transplants 114 were from multiple organ donors. There was no significant difference in 1-month serum creatinine nadir of surviving grafts (2.1 +/- 1.8 versus 1.9 +/- 1.7 mg. per dl.), 6-month serum creatinine level (1.7 +/- 0.8 versus 1.6 +/- 0.6 mg. per dl.), 12-month serum creatinine level (1.8 +/- 0.9 versus 1.6 +/- 0.6 mg. per dl.) and 5-year actuarial graft survival (44.8 +/- 4.1 versus 52.4 +/- 7.5%), with the community hospital data presented first. The delayed graft function rate was significantly higher in the recipients of cadaver kidney grafts retrieved by community hospital teams (54 versus 35%), which was reduced by the in situ flush technique. There was no significant difference in delayed graft function rate (48 versus 40%) for the 114 cadaver kidney transplants retrieved from multiple organ donors by either community hospital or transplant center teams. With continuing education and quality control, community hospital retrieval teams can provide kidneys satisfactory for transplantation, even when working with multiple organ retrieval teams.

Actuarial Analysis↗

PubMed2002

Identifying retrieval problems using the California Verbal Learning Test.

Wilde, Boake, and Sherer (1995) examined the discrepancy between Long Delayed Free Recall (LDFR) and Recognition Discriminability (RD)--the California Verbal Learning Test (CVLT) index thought to indicate the presence of memory retrieval problems--and found little evidence to recommend its use in traumatic brain injury (TBI). The present investigation re-examined this index from the perspective of a continuum of retrieval deficit severity. CVLT performance was examined in 122 TBI patients, and 2 retrieval deficit indicators of varying severity were evaluated. Memory-impaired control groups were matched with retrieval deficit groups on initial acquisition and demographic characteristics. Individuals with a LDFR/RD discrepancy did not show predicted differences on other CVLT indices of retrieval problems, similar to the findings of Wilde et al. (1995). In contrast, individuals with a consistent discrepancy between free recall and semantic cued recall (Short and Long Delay) had greater improvement with recognition cueing and made fewer intrusive errors than controls. Individuals who benefited from semantic cues (where retrieval of the target word is still required) also benefited from recognition cues (where retrieval demands are minimal). Evidence supported the existence of a continuum of retrieval deficit severity. An LDFR/RD discrepancy without performance improvement from semantic cueing appears to indicate a more severe retrieval deficit, whereas performance improvement from both recognition and semantic cueing indicates less severe retrieval deficits.

Adult↗

PubMed1999

Retrieval capabilities of different stone basket designs in vitro.

BACKGROUND AND OBJECTIVE: Several designs of endoscopic stone retrieval baskets are available. Each instrument has special characteristics which can be employed in different locations with different techniques and various effects. In this study, we compared the retrieval capability of five basket designs in two in vitro models. MATERIALS AND METHODS: The five baskets were a flat wire (Segura), Parachute, N-0-tip, and two helical designs. The ability of the baskets to retrieve beads of 4, 6, and 8 mm was compared in two models. Each size was used individually, and four beads of the 4-mm size were also studied. In the first model, single and multiple beads were placed in a cylindrical plastic tube to mimic removal of the stone from the ureter. In single-bead retrieval trials, the basket was opened beyond the bead and withdrawn, whereas with multiple beads, the basket was opened beyond, withdrawn, and closed. Bead engagement and removal was considered a successful retrieval. Three repetitions were performed for each basket and each bead size. In the second model, similar beads were placed in a round-bottom test tube to simulate a stone within a calix. The basket was opened at the base of the tube and closed. The number of beads removed was noted for three repetitions for each basket. RESULTS: All baskets were able to retrieve the 4-, 6-, and 8-mm beads from the cylinder, with the exception of the four-wire helical basket, which failed in two of the three retrieval attempts for the 4- and 6-mm beads, and the double-helical basket, which failed in two of the three retrieval attempts for the 4-mm bead. When four beads 4 mm in size were used, the Parachute and double-helical baskets retrieved all of them within two trials and the N-0-tip and four-wire helical baskets within three trials. The Segura basket failed all trials. In the test tube model, all baskets failed to remove any beads with the exception of the N-0-tip, which was successful in removing a single bead with each positioning. CONCLUSIONS: In these in vitro models, it was apparent that the design of the basket affects its ability to retrieve calculi in different situations.

Endoscopes↗