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Biomedical subjects

D S Dinner

Publications and source records attributed to D S Dinner.

At least 37 records · Page 2Linked to original sources
PubMed1997

Use of the intracarotid amobarbital procedure in the evaluation of memory.

The intracarotid amobarbital procedure (IAP) involves the temporary inactivation of one cerebral hemisphere by the injection of sodium amobarbital, which allows independent testing of the contralateral hemisphere. Initially used for lateralization of language, IAP later found a role in the evaluation of memory function in patients with intractable temporal lobe epilepsy being considered for resective surgery. IAP technique varies widely across centers, but, in general, memory is assessed by presenting the patient with a number of items during the period of hemispheric inactivation and testing recall or recognition of these items after the effect of the drug has worn off. Because the medial temporal lobe is not directly perfused by the internal carotid artery, concerns have been raised about the ability of the IAP to test hippocampal memory function. Consequently, a variety of selective procedures have been devised. Findings on both intracranial EEG recordings and pathologic and neuroimaging studies support the association of IAP memory results with hippocampal function. The IAP memory test was originally designed to predict the risk for development of global amnesia following unilateral temporal lobectomy. More recently, it also has been used as an adjunct in lateralizing the seizure focus and for predicting postoperative selective memory deficits and seizure outcome.

Adult↗
PubMed1996

The multiple sleep latency test: comparison of sleep onset criteria.

Determining sleep latency is one of the cornerstones of the interpretation of the multiple sleep latency test (MSLT). The purpose of this study was to compare various criteria used to determine sleep onset. We prospectively analyzed 100 consecutive MSLTs that were performed according to a standardized protocol. We scored each test using three separate sets of criteria for sleep onset: 1) one epoch of stage 1 sleep, 2) two consecutive epochs of stage 1 sleep, and 3) three consecutive epochs of stage 1 sleep. Each method yielded a mean sleep latency and a categorical classification of the record as normal if > 10 minutes, moderate if > or = 5 and < or = 10 minutes, and severe sleepiness if < 5 minutes. The ages of participants ranged from 4 to 78 years (mean 45.5). The averages of the mean sleep latencies across all three methods were: 6.2 minutes [standard deviation (SD) = 4.3] using one epoch, 7.2 minutes (SD = 4.7) using two epochs, and 7.5 minutes (SD = 4.9) using three epochs. Using the three categories of sleepiness, the implementation of the three-epoch criterion vs. the one-epoch criterion produced a change in category in 16 patients (16%). Five went from severe to moderate, 10 from moderate to normal, and 1 from severe to normal. As compared to using one epoch, using three produced an increase in mean sleep latency of at least 50% in 13 patients. The use of various criteria for sleep onset, especially criteria 1 and 3 above, produces differences in interpretation that are neither rare nor quantitatively negligible. Standardization of the methodology across centers would be desirable in clinical practice as well as for research protocols.

Adolescent↗
PubMed1995

Interrater reliability of the multiple sleep latency test.

The purpose of this study was to evaluate interrater reliability in the interpretation of the multiple sleep latency test (MSLT). We prospectively analyzed MSLTs performed on 21 patients with excessive daytime sleepiness. MSLTs were recorded on Grass Model 78 polygraphs with EEG, electro-oculogram, and chin EMG. Each test was performed simultaneously at paper speeds of 10 and 30 mm/sec and was scored blindly by 3 readers using standard criteria. For the quantitative variable (sleep latency), a LISREL model was used. For the binary variable (REM present or not), a kappa coefficient was used. Interrater reliability of sleep latency was 0.850 at speed 10, and 0.884 at speed 30. There was no significant difference between speed 10 and 30. Interrater reliability for the presence or absence of REM was 0.515-0.563 at speed 10, and 0.447-0.525 at speed 30. On the MSLT, the estimation of sleep latency showed excellent consistency between different readers. The determination of the presence or absence of REM only showed fair to good agreement among observers. There was no significant difference between a paper speed of 10 vs. 30 mm/sec.

Adolescent↗
PubMed1995

Objective criteria for reporting language dominance by intracarotid amobarbital procedure.

We propose a standardized method for reporting language lateralization by intracarotid amobarbital procedure (IAP). We retrospectively reviewed 165 IAPs, and classified language lateralization as left, right, or bilateral by three different methods, all based on the duration of speech arrest following each injection: absolute duration, side-to-side difference, and a "laterality index" defined as (L-R/L+R). Cutoff values were obtained by studying a pure subgroup of left hemisphere dominant right-handed subjects. In 142 patients (86%), the classification remained unchanged among all three methods: left in 112 (79%), right in 19 (13%), and bilateral in 11 (8%). In the other 23 patients (14%), language classification varied among the three criteria used. The change of category was never between left and right, and always involved bilateral language. Thus, this index may be helpful in standardizing and comparing IAP results from different series.

Adolescent↗
PubMed1995

Dreams and rapid eye movement sleep in the multiple sleep latency test.

Dreams are closely associated with rapid eye movement (REM) sleep. The purpose of this study was to evaluate the reliability of dreams in predicting the presence of REM sleep during naps of the multiple sleep latency test (MSLT). We prospectively analyzed MSLTs performed in the evaluation of 44 patients with excessive daytime sleepiness. A total of 167 naps were studied. The patients' ages ranged from 11 to 69 years (mean 45 years). There were 26 males and 18 females. The relationship between the presence of reported dreams and the presence of REM sleep was as follows: sensitivity (percentage of naps with REM in which dreams were reported), 59%; specificity (percentage of naps without REM in which no dreams were reported), 63%; positive predictive value (probability that REM occurred if dreaming is present), 29%; and negative predictive value (probability that REM did not occur when no dreaming is present), 85%. In the daytime naps of the MSLT, the presence of reported dreaming did not appear to be a reliable indicator of the presence of REM sleep in the preceding nap.

Adolescent↗
PubMed1995

Intracarotid amobarbital procedure as a predictor of material-specific memory change after anterior temporal lobectomy.

Memory testing during the intracarotid amobarbital procedure (IAP) is used extensively to identify temporal lobe surgery candidates "at risk" for developing severe postoperative anterograde amnesia. However, the utility of the IAP in predicting commonly observed material-specific memory deficits has not been thoroughly investigated. We examined the utility of contralateral IAP memory testing, as an index of the functional capacity of the surgical temporal lobe, to predict postoperative material-specific memory changes on the Wechsler Memory Scale-Revised (WMS-R) in patients with left hemisphere speech dominance undergoing left (n = 32) and right (n = 31) temporal lobectomy (TL). Left TL patients who "passed" contralateral IAP memory testing (> or = 68% recognition of memory items) had significantly greater verbal memory decrements than those who "failed" the IAP, presumably as a result of removal of functional tissue. A similar relationship between contralateral IAP performance and visual memory performance was not observed among right TL patients. Thus, the functional adequacy of the tissue to be resected appears to be inversely related to postoperative verbal memory decrement, at least among left TL patients. This relationship is consistent with results of recent studies demonstrating an inverse relationship between verbal memory decrements after left TL and preoperative neuropsychological verbal memory performance, magnetic resonance imaging (MRI) hippocampal volumes, and degree of mesiotemporal sclerosis (MTS).

Adolescent↗
PubMed1995

Automatisms with preserved responsiveness: a lateralizing sign in psychomotor seizures.

This is a report of a 1-year prospective study to investigate how often automatisms occur with preserved responsiveness in psychomotor seizures. Responsiveness is usually impaired or lost when automatisms occur during psychomotor seizures. However, there are several anecdotal reports in the literature of patients who have automatisms with preserved responsiveness (APRs). We evaluated 123 patients with temporal lobe epilepsy (57 patients [46%] left-sided, 48 patients [39%] right-sided, and 18 patients [15%] bitemporal) with video/EEG monitoring, testing responsiveness by asking the patient to respond verbally and to follow motor commands. Seven patients (5.6%) had preserved responsiveness in the presence of prominent automatisms (lip smacking, swallowing). In 15 seizures, the responsiveness was adequately tested (3.6 questions per period of automatism). Average seizure duration was 71.6 +/- 14.8 seconds (range, 45 to 100 seconds). Average duration of automatisms was 59.5 +/- 13.5 seconds (range, 40 to 80 seconds). Ictal EEG was localized over the right temporal area in nine seizures, over the right hemisphere in five, and was nonlocalizable in one seizure. APRs never occurred in left-sided psychomotor seizures and occurred in 10% of the right temporal cases. In conclusion, APRs reliably lateralized to the right side in temporal lobe epilepsy.

Adult↗
PubMed1995

Dynamic pharyngoscopy in predicting outcome of uvulopalatopharyngoplasty for moderate and severe obstructive sleep apnea.

STUDY OBJECTIVE: We sought to determine whether preoperative fiberoptic pharyngoscopy (FOP) with Müller's maneuver (dynamic FOP) could be used to establish a subgroup of obstructive sleep apnea (OSA) patients with better outcome after uvulopalatopharyngoplasty (UPPP). DESIGN: Retrospective review of an observational cohort. SETTING: Tertiary care referral center. PATIENTS: Twenty-nine patients who underwent UPPP and nasopharyngeal surgery by one surgeon. INTERVENTION: The patients were divided into two groups based on the findings of preoperative dynamic FOP: group 1 (11 patients) had collapse of the velopharynx and the base of the tongue-epiglottis-hypopharynx (TEH) complex and group 2 (18 patients) had velopharyngeal collapse only. MEASUREMENTS AND RESULTS: Surgical success was defined using a conventional definition (> 50% reduction in the apnea-plus-hypopnea index [OAHI]), and a criterion for cure (> 90% reduction in OAHI and postoperative OAHI < 15). Both groups had a significant improvement in their OAHI. The success rate was significantly higher in patients with velopharyngeal collapse only compared with patients with additional collapse of the TEH complex (78 vs 36% with the conventional definition, and 50 vs 9% using the definition for cure, respectively). Predictive value of dynamic FOP in predicting cure failure when collapse of the TEH complex was present was 91%. CONCLUSIONS: Dynamic FOP may help establish a subgroup of OSA patients with greater likelihood of successful UPPP. The high negative predictive value of dynamic FOP when a criterion for cure is used suggests that this maneuver could best be used to exclude patients with TEH complex collapse from UPPP.

Adult↗
PubMed1995

Cortical electrical stimulation in humans. The negative motor areas.

Summarizing, we have presented evidence in humans for two "negative motor areas" which we had speculated play a significant role in the planning of voluntary motor movements. A review of the more recent experimental literature shows that histological, physiological, and electrical stimulation studies in animals reveal the existence of two frontal regions that from the experimental data also seem to play an essential role in the preparation (as opposed to execution) of voluntary movements. Current available evidence suggests that these two areas (areas F5 and F6 of Rizzolatti et al.) correspond to the negative motor areas we have described in human studies. Also of interest is that Broca's area in the dominant hemisphere overlaps the corresponding negative motor area. This observation suggests that Broca's area has evolved from area F5 of monkeys specializing in the planning of fine movements necessary for speech production. We feel that current evidence suggests the existence of three mechanisms by which cortical stimulation (by electrical stimulation or by epileptic activation) can generate negative motor phenomena: 1. The "silent period," which is consistently contralateral, has a somatotopic distribution, and tends to affect predominantly muscles involved in fine movements. It is of relatively short duration and seems to be generated by the activation of cortical areas in the primary sensorimotor region. The H-reflex is not inhibited during the silent period, suggesting that the silent period is generated by a decrease in the excitatory input through direct corticospinal neurons on the spinal alpha motoneurons. It is possible that in normal individuals this system is used for fine tuning of fine distal movements. The negative myoclonus seen in some patients with focal cortical epilepsy is probably generated by this mechanism. The primary and supplementary "negative motor areas" described in this chapter. This effect also has a somatotopic distribution but can affect muscle bilaterally even if there is a clear predominance contralaterally. The negative motor effect does not influence postural tone and can be prolonged. The negative motor effect is probably produced by activation of agranular cortex immediately in front of the primary and supplementary face motor area. These cortical areas are probably used for organization and integration of fine motor movement. Activation of these areas would produce an apraxia of fine movements. Focal atonic seizures are probably generated by this mechanism. 3. The fast-conducting corticoreticulospinal pathways, which by activation of the brainstem inhibitory centers (NRPo, n.r. magnocellularis dorsal beta, and NRGc), tend to produce bilateral atonia of axial, postural muscles. This system probably does not depend on the presence of the direct corticospinal pathways. By analogy with cataplexy, which is probably produced by activation of similar brainstem inhibitory systems, we would expect the H-reflex to be markedly diminished or even to disappear during the atomic phase (64). This pathway would be used normally for postural adjustments and locomotion. The bilateral massive atonic seizures, seen most frequently in patients with severe and diffuse cortical lesions, are probably produced by this mechanism. However, the bilateral atonic seizures occasionally seen in patients with focal cortical lesions may also be produced by a similar mechanism.

Brain↗
PubMed1994

Functional anatomy of the human supplementary sensorimotor area: results of extraoperative electrical stimulation.

Electrical stimulation studies have demonstrated that a "supplementary motor area" (SMA) exists in humans. However, its precise functional organization has not been well defined. We reviewed the extraoperative electrical stimulation studies of 15 patients with intractable epilepsy who were evaluated with chronically implanted interhemispheric subdural electrodes. SMA-type positive motor responses were elicited not only from the mesial portion of the superior frontal gyrus but also from its dorsal convexity, and from the paracentral lobule, cingulate gyrus, and precuneus. Sensory symptoms, that could not be attributed to stimulation of the primary sensory area, were elicited from the superior frontal and cingulate gyri in addition to the precuneus. Therefore, human SMA, as defined by electrical stimulation, is not always confined to the mesial portion of the superior frontal gyrus as described previously. It is also not strictly "motor" but "sensorimotor" in representation. We propose referring to this region as the "supplementary sensorimotor area" (SSMA). We observed a somatotopic organization within the SSMA with an order of lower extremity, upper extremity, and head from posterior to anterior. Sensory representation in an individual was either anterior or posterior to the positive motor representation but never both. There was a supplementary eye field within the head representation. A supplementary negative motor area was noted at the anterior aspect of the SSMA. No language area was demonstrated within the SSMA. The physiologic significance of the SSMA and functional consequences of its resection must be addressed in further studies.

Adolescent↗
PubMed1994

Lennox-Gastaut syndrome in the elderly?

The Lennox-Gastaut syndrome (LGS) is an electro-clinical syndrome of early childhood that consists of mental retardation, intractable generalized epilepsy with multiple seizure types, and typical EEG findings. We report a 64-year-old woman who was referred for presurgical evaluation with a diagnosis of intractable temporal lobe epilepsy since the age of 14 years, consisting of staring and unresponsiveness, sudden falls, and generalized convulsions. The average seizure frequency was 1-4 per month. Mental status and neurological examination were normal. There was no known etiology and magnetic resonance imaging (MRI) of the brain was normal. Interictal EEG showed findings characteristic of LGS: generalized slow spike-wave complexes, multifocal sharp waves, generalized polyspikes and paroxysmal fast activity during sleep. Despite the absence of mental retardation and the presence of normal alpha rhythm, the patient fulfills most diagnostic criteria for LGS, with unusually late onset and extremely delayed diagnosis. This case illustrates the controversial nosologic boundaries of the syndrome. Prolonged EEG video monitoring may be of value even in the elderly. The LGS and other varieties of secondary generalized epilepsy should be considered in the syndromic diagnosis of epilepsy in the elderly.

Age of Onset↗
PubMed1993

Presurgical evaluation of temporal lobe epilepsy using interictal temporal spikes and positron emission tomography.

OBJECTIVE: Our goal was to determine the role of fludeoxyglucose F 18-positron emission tomography (18FDG-PET) and interictal temporal spikes in lateralizing the epileptogenic region in patients who (1) were diagnosed as having temporal lobe epilepsy based on clinical symptoms and exclusively temporal interictal spikes and (2) did not have a structural lesion on magnetic resonance imaging. DESIGN: This was a retrospective study of 40 consecutive patients fulfilling the above criteria who underwent 18FDG-PET scanning. A firm electrophysiologic diagnosis and 1 complete year of postsurgical follow-up, where applicable, were required. Outcome measures included surgical outcome and final electrophysiologic diagnosis. RESULTS: Unilateral, interictal temporal spikes (ITS) were present in 33 (82.5%) of 40 patients. Seven patients (17.5%) had bitemporal, independent spikes. Thirty-one (77.5%) of 40 patients had unilateral temporal hypometabolism (TH). Twenty-eight (70%) patients had concordant TH and ITS. One year after surgery, 31 of 33 patients with unilateral ITS were greatly improved; two of five who had bitemporal ITS showed similar improvement. In 28 patients, unilateral TH and unilateral ITS were concordant. The paired result always concurred with the final neurophysiologic assessment. Surgical outcome between patients with 18FDG-PET showing unilateral TH (26 of 30 greatly improved) and those not showing unilateral TH (six of eight greatly improved) was not significantly different. CONCLUSION: In temporal lobe epilepsy not associated with a mass lesion, unilateral ITS are reliable lateralizing features and suggest a good surgical outcome. Use of 18FDG-PET provides corroborative lateralizing information but 18FDG-PET that fails to show unilateral TH does not preclude a good surgical outcome.

Action Potentials↗
PubMed1993

Comprehension deficits elicited by electrical stimulation of Broca's area.

We report on three patients with intractable focal seizures arising from the language-dominant left hemisphere. In the work-up prior to surgical treatment, arrays of subdural electrodes were placed over the left temporal lobe and adjacent supra-Sylvian region. Electrical stimulation of the inferior frontal cortex language region ('Broca's area') produced marked interference with language output functions including speech arrest, slowing of oral reading, paraphasia and anomia. At some cortical language sites in this region cortical stimulation also produced language comprehension deficits, particularly in response to more complex auditory verbal instructions and visual semantic material. The severe impairment of comprehension verbal information was in clear contrast with ability to process non-verbal material, which was not affected.

Adolescent↗
PubMed1992

Polysomnography.

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Brain↗