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PubMed1994

The palatal canine and the adjacent lateral incisor: a study of a west of Scotland population.

The hypothesis that palatally-displaced canines are associated with smaller than average lateral incisors or with congenital absence of adjacent lateral incisors was tested on a West of Scotland population. A retrospective study of the records of orthodontic patients attending Glasgow Dental Hospital was carried out. One-hundred-and-eighty-two subjects with palatally displaced canines were identified. The tooth length of lateral and central incisors was measured on radiographs and the crown widths of lateral incisors were measured on study casts. One-hundred-and-six extracted maxillary lateral incisors were examined to allow more accurate measurement of crown width and root length than was possible from radiographs. An association was sought between the size of the lateral incisor or its absence, the position of the adjacent maxillary canine, and between crown size and root length of the lateral incisor. The conclusions supported the hypothesis that there is a weak association between palatally displaced maxillary canines and lateral incisors of smaller than average crown width. There was weak support for the association between palatal canines and absence of the adjacent lateral incisor. There was no correlation between lateral incisor crown width and root length.

Adolescent↗
PubMed2001

Twisting and bending: the functional role of salamander lateral hypaxial musculature during locomotion.

The function of the lateral hypaxial muscles during locomotion in tetrapods is controversial. Currently, there are two hypotheses of lateral hypaxial muscle function. The first, supported by electromyographic (EMG) data from a lizard (Iguana iguana) and a salamander (Dicamptodon ensatus), suggests that hypaxial muscles function to bend the body during swimming and to resist long-axis torsion during walking. The second, supported by EMG data from lizards during relatively high-speed locomotion, suggests that these muscles function primarily to bend the body during locomotion, not to resist torsional forces. To determine whether the results from D. ensatus hold for another salamander, we recorded lateral hypaxial muscle EMGs synchronized with body and limb kinematics in the tiger salamander Ambystoma tigrinum. In agreement with results from aquatic locomotion in D. ensatus, all four layers of lateral hypaxial musculature were found to show synchronous EMG activity during swimming in A. tigrinum. Our findings for terrestrial locomotion also agree with previous results from D. ensatus and support the torsion resistance hypothesis for terrestrial locomotion. We observed asynchronous EMG bursts of relatively high intensity in the lateral and medial pairs of hypaxial muscles during walking in tiger salamanders (we call these 'alpha-bursts'). We infer from this pattern that the more lateral two layers of oblique hypaxial musculature, Mm. obliquus externus superficialis (OES) and obliquus externus profundus (OEP), are active on the side towards which the trunk is bending, while the more medial two layers, Mm. obliquus internus (OI) and transversus abdominis (TA), are active on the opposite side. This result is consistent with the hypothesis proposed for D. ensatus that the OES and OEP generate torsional moments to counteract ground reaction forces generated by forelimb support, while the OI and TA generate torsional moments to counteract ground reaction forces from hindlimb support. However, unlike the EMG pattern reported for D. ensatus, a second, lower-intensity burst of EMG activity ('beta-burst') was sometimes recorded from the lateral hypaxial muscles in A. tigrinum. As seen in other muscle systems, these beta-bursts of hypaxial muscle coactivation may function to provide fine motor control during locomotion. The presence of asynchronous, relatively high-intensity alpha-bursts indicates that the lateral hypaxial muscles generate torsional moments during terrestrial locomotion, but it is possible that the balance of forces from both alpha- and beta-bursts may allow the lateral hypaxial muscles to contribute to lateral bending of the body as well.

Ambystoma↗
PubMed2000

The origin and development of the upper lateral incisor and premaxilla in normal and cleft lip/palate monkeys induced with cyclophosphamide.

OBJECTIVE: Cleft lip/palate (CLP) is a common human congenital defect in which the maxillary lateral incisors are often absent, malformed, and malpositioned. The present study was designed to examine the origin of the upper primary lateral incisor relative to the medial nasal process (MNP) and maxillary process (MP) fusion area and to the premaxillary/maxillary (incisive) suture in monkeys. METHOD: Scanning electron microscopy, histology, skeletal staining, and drying techniques were used to study facial development in embryo and fetal monkey specimens. A teratogenic dose of cyclophosphamide was administered to pregnant monkeys prior to fusion of the MNP and MP and fetuses were examined for CLP. RESULTS: Formation of the anterior maxilla involved fusion of the MNP and MP at stages 14-18. At stages 18-20, the palatal portion of the MNP had formed the medial and lateral incisive mounds. By stage 22, the upper primary lateral incisor has formed within the MP, lateral to the MNP/MP fusion area and to the ossifying premaxilla. Ossification of the premaxilla begins in the MNP and subsequently spreads laterally across the MNP/MP fusion area into the MP. Accordingly, the lateral incisor undergoes a complex positional shift (mainly medial) relative to the incisive suture both prenatally and postnatally and is finally located medial to the suture. Examination of the cyclophosphamide-induced CLP fetuses showed that the lateral incisor is located lateral to the alveolar cleft and does not shift medial to the incisive suture. CONCLUSION: Understanding the origin of the lateral incisor (the tooth closest to the cleft) and the shift after its formation provides clues to high incidence of malformations and ectopia of this incisor in cleft patients.

Alveolar Process↗
PubMed2001

Abnormal superior popliteomeniscal fascicle and posterior pericapsular edema: indirect MR imaging signs of a lateral meniscal tear.

OBJECTIVE: Because MR diagnosis of lateral meniscal tears can be difficult, indirect signs may be useful when a tear is suspected. We studied whether an abnormality of the superior popliteomeniscal fascicle or pericapsular edema was associated with lateral meniscal tears and thus may be an indirect MR imaging sign of a lateral meniscal tear. MATERIALS AND METHODS: We identified 59 consecutive patients who underwent both knee MR imaging examinations and knee arthroscopy. Thirty patients had lateral meniscal tears, and 29 had intact lateral menisci. We reviewed paired sagittal proton density- and T2-weighted MR images from these 59 patients for abnormal superior popliteomeniscal fascicles and edema surrounding the posterolateral capsule. RESULTS: The superior popliteomeniscal fascicles were abnormal in nine of the 30 patients with torn lateral menisci but were normal in all 29 patients with intact menisci (p = 0.001). Abnormal fascicles were apparent only when the lateral meniscal tear involved the posterior horn. Posterior pericapsular edema was seen in 10 patients with a torn posterior horn and in one patient with an anterior horn tear of the lateral meniscus, but in only two patients with intact menisci (p = 0.006). CONCLUSION: The presence of superior popliteomeniscal fascicle abnormalities and of posterior pericapsular edema is significantly associated with a tear of the lateral meniscus, most commonly in the posterior horn. Noting the presence of these findings may help improve the accuracy of MR diagnosis of lateral meniscal tears.

Adolescent↗
PubMed1983

Modified contemporary comparison sire evaluations from first, all, and later lactations.

Modified Contemporary Comparisons are calculated by the United States Department of Agriculture from first and later lactations, results of which form the published progeny evaluations for all lactations. Characteristics of such evaluations on 200 Holstein sires, each with more than 500 daughters in each data set in the Summer 1981 run, were studied. Predicted Differences for milk averaged 245, 286, and 292 kg for first, all, and later lactation evaluations, with standard deviations of 271, 253, and 254 kg. The average difference (later minus first) was 47 kg (standard deviation, 149 kg). Average absolute difference was 123 kg (standard deviation, 97 kg). Correlations were .95 between first and all, .84 between first and later, and .97 between all and later. The correlation between progeny test for first lactation and difference was -.38 (-.28 for absolute difference). Percent of first lactations culled was correlated -.49, -.47, and -.37 for first, all, and later evaluations. Important variables in prediction of later lactations were first, percent of firsts culled, and sire's age, with first alone producing a coefficient of determination of .71. Sire's age was correlated -.11, -.19, and -.23 with first, all, and later evaluations indicating possible differences in genetic trend for first and later progeny tests for these sires. Fat yield behaved similarly to milk except that correlations between progeny tests and sire's age or culling were less than for milk. Ranking of bulls for daughter milk yield in later lactation changed from first lactation.

Age Factors↗
PubMed1985

Differences in modified contemporary comparison sire evaluations from first and later lactations by breed.

Sire evaluations from three sets of daughter records, first records only (first), later records after firsts (later), and all records (all) by Modified Contemporary Comparison procedures were used to examine differences in first and later lactation evaluations by breed. January 1984 evaluations for milk for 767 Ayrshires, 3,175 Guernsey, 29,498 Holstein, 3,530 Jersey, and 984 Brown Swiss bulls with 10 or more daughters in each set were used. Average differences between evaluations (later minus first) were 36, 0, 6, 35, and 35 kg milk for Ayrshire, Guernsey, Holstein, Jersey, and Brown Swiss bulls. Standard deviations of the difference were 114, 94, 142, 91, and 134 kg, showing considerable sire-to-sire variation in difference. Correlations between evaluations based on first and later records were .84 to .86 for all breeds except .92 for Jerseys. Percent of first lactations culled was correlated .20, .18, .16, .16, and .19 with difference for Ayrshire, Guernsey, Holstein, Jersey, and Brown Swiss, indicating that culling produced larger differences between evaluations for first and later lactations in favor of later evaluations. Prediction of sire evaluation from later records was enhanced by knowledge of sire's age in addition to first evaluation for Guernsey, Holstein and Jersey sires. In these breeds, for a constant first evaluation, and percent culled in first lactation, younger bulls had higher evaluations from later records. This study showed important differences between evaluations from first and later records for all breeds.

Animals↗
PubMedDate not supplied

Teaching cognitive rehearsal as a shield for lateral violence: an intervention for newly licensed nurses.

BACKGROUND: Recent literature defines lateral violence as nurses covertly or overtly directing their dissatisfaction inward toward each other, toward themselves, and toward those less powerful than themselves. Newly licensed nurses are an identified group that is vulnerable to lateral violence during their socialization to nursing practice. The use of cognitive rehearsal, an applied cognitive-behavioral technique, was used as an intervention and the theoretical underpinning for this study. METHOD: Twenty-six newly licensed nurses hired by a large acute care tertiary hospital in Boston, Massachusetts, participated in an exploratory descriptive study. They were taught about lateral violence in nursing practice and the use of cognitive rehearsal techniques as a shield from the negative effects of lateral violence on learning and socialization. Small laminated cueing cards with written visual cues for the appropriate responses to the most common forms of lateral violence were provided. One year later, videotaped focus groups designed to collect qualitative data about the applied intervention were conducted. RESULTS: Twenty-six newly licensed nurses in three different focus groups were videotaped responding to six open-ended questions designed to elicit information on their experience with lateral violence, use of cognitive rehearsal as an intervention, and the overall socialization process. CONCLUSIONS: Knowledge of lateral violence in nursing appeared to allow newly licensed nurses to depersonalize it, thus allowing them to ask questions and continue to learn. The learned cognitive responses helped them confront the lateral violence offender. Confrontation was described as difficult but resulted in the resolution of the lateral violence behavior. Overall, the retention rate in this study population was positively affected.

Attitude of Health Personnel↗
PubMed2002

The clinical study of lateral orbitotomy.

OBJECTIVE: To observe the effect of lateral orbitotomy. METHODS: Lateral orbitotomy for orbital tumors within muscle cone and area of lacrimal gland was performed for 70 cases by standard lateral orbitotomy, modified lateral orbitotomy and lateral orbitotomy combined with medial orbitotomy from July 1999 to April 2001 in Armed Police General Hospital. RESULTS: The indications of standard lateral orbitotomy were suitable for the orbital tumor below the optic nerve (38 cases), and modified lateral orbitotomy (involving supra or infra orbital edge) for the orbital tumors above the optic nerve (28 cases), as well as lateral orbitotomy combined with medial orbitotomy for the orbital tumors surrounding the optic nerve (4 cases). There were total removal of orbital tumors in 63 cases, partial removal 4 cases, decompression 3 cases of Graves' diseases. CONCLUSION: The indications of lateral orbitotomy depend on the category, location and extent of orbital tumors. Lateral orbitotomy involving supra or infra orbital edge enlarges the operative field, and improves the successful rate of orbital removal.

Graves Disease↗
PubMed1992

Primary projections of the lateral line nerves in larval sea lamprey, Petromyzon marinus L. An HRP study.

The primary central projections of the anterior and posterior lateral line nerves were determined in the larval sea lamprey, Petromyzon marinus L. using silver staining methods and axonal transport of horseradish peroxidase (HRP). Lateral line fibers course in the dorsal portion of the octavolateral area. At the level of their entry in the medulla, all the lateral line fibers originate ascending and descending branches. The anterior lateral line nerve consists of three roots: dorsal, intermediate and ventral. Afferents of the dorsal root project to the ipsilateral dorsal nucleus. The intermediate and ventral roots project ipsilaterally to the lateral neuropil of the medial nucleus and to the cerebellar lamina, but they do not cross the midline. Contralateral projections of this nerve were not found in larvae. Primary afferents of the posterior lateral line nerve project ipsi- and contralaterally to the medial neuropil of the medial nucleus. Ascending fibers course in the ipsilateral medial nucleus, enter the cerebellar lamina, cross the midline and descend to the lateral neuropil of the contralateral medial nucleus. In the cerebellar lamina, the fibers of the anterior lateral nerve are located ventrolaterally to those of the posterior lateral nerve. Lateral line efferents were not observed in larvae.

Animals↗
PubMed2003

The relationship of lateral release and tourniquet deflation in total knee arthroplasty.

A total of 242 knees in 198 patients undergoing total knee arthroplasty were reviewed to evaluate the effect of tourniquet deflation on lateral release rates, possible variables associated with the need for lateral release, and adequacy of intraoperative evaluation on final radiographs. The need for lateral release was determined using the "no-thumbs" and "full contact" rules and visual evaluation. Lateral release was performed after tourniquet deflation. A total of 171 (71%) knees needed a lateral release before tourniquet deflation. After tourniquet deflation, only 53 (22%) required lateral release, representing a 69% reduction. Obesity was the only other significant factor in lateral release requirement. Based on the observations of this study, it is recommended that the need for lateral release be evaluated after tourniquet deflation. A 69% reduction in lateral release supports the hypothesis that tourniquet pressure has an effect on patellar tracking. Lateral release appears to be effective in restoring normal patellar tilt, and obesity increases its need.

Adult↗
PubMed1990

The lateral transverse thigh free flap: an alternative for autogenous-tissue breast reconstruction.

The lateral transverse thigh free flap is a horizontal variant of the more commonly known vertical tensor fasciae latae myocutaneous free flap. Fresh cadaver injections of the lateral circumflex femoral artery indicated simultaneous perfusion of the upper lateral thigh tissues and the standard tensor fasciae latae territory extending down the lateral thigh. These experimental data strongly indicated that the clinical application would be successful. The flap is composed mostly of fat from the prominence of the upper lateral thigh ("saddlebags") based on a small plug of underlying tensor fasciae latae muscle. The amount of skin that can be included with this flap is limited in a vertical dimension to about 6 to 8 cm but is determined by the ability to close the defect. We have performed 17 flaps in 11 patients with up to 18 months of follow-up. Ten were delayed and 7 were immediate reconstructions. The chest and hip dissections are performed simultaneously by two microsurgeons. There has been one flap loss due to arterial disruption on day 3. An early problem was seroma formation in the donor site, which has been improved in the later patients by closing the dead space with sutures. The lateral transverse thigh free flap has the following advantages over other methods of autogenous-tissue breast reconstruction: (1) longer, more peripherally placed vessels, (2) easier flap dissection and no need to turn the patient during the procedure, (3) decreased postoperative morbidity and more rapid recovery, (4) reduction of an area of excess fat in those patients in whom the hips are more prominent than the abdomen, (5) greater intrinsic internal projection of the flap, and (6) excellent vascularity. The disadvantages of the flap are (1) microsurgery is required, (2) the amount of skin available is not as great as that with the gluteal or transverse rectus abdominis musculocutaneous (TRAM) flap, (3) the scar on the upper lateral thigh is probably more visible than on the buttock or the abdomen, and (4) a balancing procedure on the opposite hip is usually necessary in unilateral cases. Our current indications for the lateral transverse thigh free flap are (1) the transverse rectus abdominis musculocutaneous flap is unavailable, (2) for a particular breast size, the thigh fat proportions are greater than the abdominal proportions, or (3) the patient prefers this option to the transverse rectus abdominis musculocutaneous or gluteus flap. Results and complications with the lateral transverse thigh free flap will be presented along with pertinent comparisons with the other choices for autogenous-tissue breast reconstruction.

Adult↗
PubMed1978

The effects of minor degrees of obliquity on the lateral chest radiograph.

Minor degrees of obliquity affect the appearance of the lateral chest radiograph. For 100 normal subjects we compared findings on three left lateral projections: the "straight lateral", rotation of the subject's right side 10 degrees anterior ("right anterior"), and rotation of the patient's right side 10 degrees posterior ("right posterior"). A number of structures appeared generally best seen in the "right anterior" lateral projection, less well seen in the "straight posterior" lateral projection and least well seen in "right posterior" lateral projection. These structures were the epicardial fat stripe and pericardial line, the anterior margin of the ascending aorta, the hilar vessels, the origins of the upper lobe bronchi, and the posterior wall of the bronchus intermedius. The heart appeared largest in the "right anterior" lateral view, while in the "right posterior" lateral view it appeared smallest (whether assessed subjectively or by measurement of posterior left ventricular overlap of the inferior vena cava). Similarly, the hilar vascular shadows and major bronchi were most prominent when rotated apart in the "right anterior" projection and least prominent when more nearly superimposed in the "right posterior" projection. Slight rotation showed no significant effect on the anteroposterior diameter of the trachea, the width of the left pulmonary artery, or the diameters of the upper lobe bronchi. The azygos vein and a well visualized posterior tracheal band were seen in a few patients. They tended to be best and most frequently seen in the "right posterior" lateral view. Either obliquity tended to improve delimeation of the anterior pleural margins and the costophrenic angles. This was also true for the interlobar fissures, but confusing superimposition shadows were less likely in the "right anterior" than the "right posterior" lateral radiograph.

Aortography↗
PubMed2000

Electroencephalographic, volumetric, and neuropsychological indicators of seizure focus lateralization in temporal lobe epilepsy.

CONTEXT: Anterior temporal lobectomy is an effective treatment for medically intractable temporal lobe seizures. Identification of seizure focus is essential to surgical success. OBJECTIVE: To examine the usefulness of presurgical electroencephalography (EEG), magnetic resonance imaging (MRI), and neuropsychological data in the lateralization of seizure focus. DESIGN: Presurgical EEG, MRI, and neuropsychological data were entered, independently and in combination, as indicators of seizure focus lateralization in discriminant function analyses, yielding correct seizure lateralization rates for each set of indicators. SETTING: Comprehensive Epilepsy Program, Shands Teaching Hospital, University of Florida, Gainesville. PATIENTS: Forty-four right-handed adult patients who ultimately underwent successful anterior temporal lobectomy. Left-handed patients, those with less-than-optimal surgical outcome, and any patients with a history of neurological insult unrelated to seizure disorder were excluded from this study. MAIN OUTCOME MEASURES: For each patient presurgical EEG was represented as a seizure lateralization index reflecting the numbers of seizures originating in the left hemisphere, right hemisphere, and those unable to be lateralized. Magnetic resonance imaging data were represented as left-right difference in hippocampal volume. Neuropsychological data consisted of mean scores in each of 5 cognitive domains. RESULTS: The EEG was a better indicator of lateralization (89% correct) than MRI (86%), although not significantly. The EEG and MRI were significantly superior to neuropsychological data (66%) (P=.02 and .04, respectively). Combining EEG and MRI yielded a significantly higher lateralization rate (93%) than EEG alone (P<.01). Adding neuropsychological data improved this slightly (95%). CONCLUSIONS: The EEG and MRI were of high lateralization value, while neuropsychological data were of limited use in this regard. Combining EEG, MRI, and neuropsychological improved focus lateralization relative to using these data independently.

Adult↗
PubMed1985

Lateralizing effects of apomorphine on taxis, postural support and rotation in rats.

Subcutaneous injections of apomorphine, a dopamine receptor agonist, induced a lateralization of taxis for edges in 16% of rats and a reliable lateralization of postural support in 82% of rats. The relation among these effects and the lateralizing effects of apomorphine on rotational behavior were examined. Lateralized rotation did not reliably correlate with lateralized taxis. However, it correlated with a relatively large asymmetry of postural support. The lateralizing effects of apomorphine on taxis and rotation may reflect attentional and directional asymmetries, respectively. It is proposed that apomorphine can induce different types of lateralizations, including attentional, postural and directional, and that the lateralizing effects of apomorphine on posture and locomotor direction are interrelated. Regional brain interhemispheric asymmetries in the responsiviness of dopamine receptors may underlie different types of apomorphine-induced lateralizations.

Animals↗
PubMed2002

Mapping lateralization of click trains in younger and older populations.

The main purpose of this study was to describe and compare lateralization of earphone-presented stimuli in younger and older individuals. Lateralization functions, relating perceived location to either interaural time differences (ITDs) or interaural level differences (ILDs) were determined for 78 subjects, aged 21-88 years, who responded by pressing one of nine keys to indicate the perceived location of the stimulus. All subjects were healthy, without any history of hearing loss or ear surgery and within the normal pure tone audiometric range for their age group. Interaural pure tone and click thresholds did not differ by more than 5 dB across ears. The ILD lateralization functions, ranging from 10 dB favoring the left ear to 10 dB favoring the right ear were linear. In contrast, the ITD lateralization functions were S-shaped with a clear linear component ranging from 750 micros favoring one ear to 750 micros favoring the other ear and with an asymptote from 750 micros to 1 ms. The same general shape of the ITD and ILD lateralization functions was found at all ages, but the linear slope of the ITD lateralization function became shallower with age. The ability to discriminate midline-located click trains (ITD and ILD=0) from ITD-lateralized click trains deteriorated with age, while the comparable ability to discriminate ILD-lateralized click trains did not change significantly with age. The data support two general conclusions. First there seems to be an overall reduction in the range of ITD-based lateralization due to aging. Second, there is a greater reduction in sensitivity due to aging in changes from the perceived midline position (ITD and ILD=0) when ITD is manipulated than when ILD is manipulated.

Acoustic Stimulation↗
PubMed2005

Left hippocampal pathology is associated with atypical language lateralization in patients with focal epilepsy.

It is well recognized that the incidence of atypical language lateralization is increased in patients with focal epilepsy. The hypothesis that shifts in language dominance are particularly likely when epileptic lesions are located in close vicinity to the so-called language-eloquent areas rather than in more remote brain regions such as the hippocampus has been challenged by recent studies. This study was undertaken to assess the effect of lesions in different parts of the left hemisphere, lesions present during language acquisition, on language lateralization. We investigated 84 adult patients with drug-resistant focal epilepsy with structural lesions and 45 healthy control subjects with an established functional MRI language paradigm. Out of the 84 patients 43 had left hippocampal sclerosis, 13 a left frontal lobe lesion and 28 a left temporal-lateral lesion. All these lesions were likely to have been present during the first years of life during language acquisition. To assess the lateralization of cerebral language representation globally as well as regionally, we calculated lateralization indices derived from activations in four regions of interest (i.e. global, inferior frontal, temporo-parietal and remaining prefrontal). Patients with left hippocampal sclerosis showed less left lateralized language representations than all other groups of subjects (P < 0.005). This effect was independent of the factor of region, indicating that language lateralization was generally affected by a left hippocampal sclerosis. Patients with left frontal lobe or temporal-lateral lesions displayed the same left lateralization of language-related activations as the control subjects. Thus, the hippocampus seems to play an important role in the establishment of language dominance. Possible underlying mechanisms are discussed.

Adolescent↗
PubMed2005

Enhanced schooling performance in lateralized fishes.

The occurrence of functional left-right cerebral asymmetries has been documented in a wide range of animals, suggesting that the lateralization of cognitive functions enjoys some kind of selective advantage over the bilateral control of the same functions. Here, we compared schooling performance of fishes with high or low degree of lateralization, which were obtained through selective breeding. Schools of lateralized fishes moving in a novel environment showed significantly more cohesion and coordination than schools of non-lateralized (NL) fishes. Pairs of fishes lateralized in opposite directions were as efficient as pairs of same laterality, suggesting that the performance of lateralized fishes derives from a computational advantage rather than being the consequence of a behavioural similarity among schoolmates. In schools composed of both lateralized and NL fishes, the latter were more often at the periphery of the school while lateralized fishes occupied the core, a position normally safer and energetically less expensive.

Analysis of Variance↗
PubMed1998

Lateralization and binaural discrimination of patients with pontine lesions.

Lateralization and just-noticeable difference (jnd) measurements relative to the center were tested in a large group of patients with pontine lesions caused either by stroke or multiple sclerosis. Stimuli included binaural clicks, and low- and high-frequency narrow-band noise bursts. Two major types of abnormalities were revealed in the lateralization performances: perception of all stimuli, regardless of interaural differences (time and/or level) in the center of head (center-oriented), or lateralization of all stimuli to one side or the other of the head (side-oriented). The only significant correlation between jnd and lateralization performances was that an elevated jnd was always manifested in abnormal lateralization, while abnormality in lateralization did not necessarily indicate an abnormal jnd. Center-oriented lateralization was observed either for both interaural differences or only for one of them, and was found in both MS and stroke patients. All side-oriented stroke patients were similarly unable to center binaural stimuli for both time and level cues, whereas only one MS patient had this abnormality for interaural time differences, while his level performance was normal. More abnormalities were detected in the narrow band stimuli tests, although in some cases performance was more degraded for click stimuli. Lateralization tasks with high-frequency stimuli were more sensitive detectors of abnormality than jnd for any kind of stimulus, or lateralization tasks with low-frequency stimuli or clicks.

Adult↗