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Biomedical subjects

D S Dinner

Publications and source records attributed to D S Dinner.

At least 19 recordsLinked to original sources

Predictors of outcome after temporal lobectomy for the treatment of intractable epilepsy.

To assess short- and long-term seizure freedom, the authors reviewed 371 patients who underwent anterior temporal lobectomy to treat pharmacoresistant epilepsy. The mean follow-up duration was 5.5 years (range 1 to 14.1 years). Fifty-three percent of patients were seizure free at 10 years. The authors identified multiple predictors of recurrence. Results of EEG performed 6 months postoperatively correlated with occurrence and severity of seizure recurrence, in addition to breakthrough seizures with discontinuation of antiepileptic drugs.

Anterior Temporal Lobectomy↗

Aphasia after hemispherectomy in an adult with early onset epilepsy and hemiplegia.

A 55 year old left handed man with left hemisphere subcortical encephalomalacia, seizures, language impairment, and right hemiparesis from a motor vehicle accident at age five was evaluated for epilepsy surgery. The patient continued to speak and followed commands during a left intracarotid amobarbital test (IAT). Left functional hemispherectomy resulted in expressive aphasia. Based on postoperative outcome, language was bilateral. The injury after primary development of language function, the predominantly subcortical lesion, and the late timing of surgical intervention well past development and plasticity may have been factors in the emergence of postoperative aphasia.

Accidents, Traffic↗

Complications of invasive video-EEG monitoring with subdural grid electrodes.

OBJECTIVE: To evaluate the risk factors, type, and frequency of complications during video-EEG monitoring with subdural grid electrodes. METHODS: The authors retrospectively reviewed the records of all patients who underwent invasive monitoring with subdural grid electrodes (n = 198 monitoring sessions on 187 patients; median age: 24 years; range: 1 to 50 years) at the Cleveland Clinic Foundation from 1980 to 1997. RESULTS: From 1980 to 1997, the complication rate decreased (p = 0.003). In the last 5 years, 19/99 patients (19%) had complications, including two patients (2%) with permanent sequelae. In the last 3 years, the complication rate was 13.5% (n = 5/37) without permanent deficits. Overall, complications occurred during 52 monitoring sessions (26.3%): infection (n = 24; 12.1%), transient neurologic deficit (n = 22; 11.1%), epidural hematoma (n = 5; 2.5%), increased intracranial pressure (n = 5; 2.5%), and infarction (n = 3; 1.5%). One patient (0.5%) died during grid insertion. Complication occurrence was associated with greater number of grids/electrodes (p = 0.021/p = 0.052; especially >60 electrodes), longer duration of monitoring (p = 0.004; especially >10 days), older age of the patient (p = 0.005), left-sided grid insertion (p = 0.01), and burr holes in addition to the craniotomy (p = 0.022). No association with complications was found for number of seizures, IQ, anticonvulsants, or grid localization. CONCLUSIONS: Invasive monitoring with grid electrodes was associated with significant complications. Most of them were transient. Increased complication rates were related to left-sided grid insertion and longer monitoring with a greater number of electrodes (especially more than 60 electrodes). Improvements in grid technology, surgical technique, and postoperative care resulted in significant reductions in the complication rate.

Adolescent↗

Symptomatic or cryptogenic partial epilepsy of childhood onset: fourteen-year follow-up.

This study reports on the seizure and psychosocial outcome of 29 patients with electroclinically well-defined childhood-onset symptomatogenic or cryptogenic partial epilepsy with complex partial seizures who were followed prospectively over 14 years. Many were refractory at the time of enrollment. At 14-year follow-up, we acquired information on seizure type and frequency, psychiatric history, substance abuse, criminal activity, in addition to educational, vocational, and marital status through chart reviews and/or structured telephone interviews. Sixteen patients were only treated medically. They were divided by their following responses to medications: eight patients with less than one seizure per month were in the medically responsive group and eight patients with at least one seizure per month constituted the medically refractory group. Thirteen patients underwent focal resection for medically refractory epilepsy. Medically refractory patients displayed worse educational, vocational, social, and behavioral outcomes than medically responsive patients. Behavioral abnormalities persisted or evolved in five medically refractory patients when they became seizure free. Other studies have indicated that patients with medically refractory complex partial seizures have poor psychosocial outcomes. Although behavioral problems can occur even when seizures are well controlled, their early detection and treatment may be essential to the improvement of psychosocial outcomes.

Adult↗

Deep brain stimulation in epilepsy.

Since the pioneering studies of Cooper et al. to influence epilepsy by cerebellar stimulation, numerous attempts have been made to reduce seizure frequency by stimulation of deep brain structures. Evidence from experimental animal studies suggests the existence of a nigral control of the epilepsy system. It is hypothesized that the dorsal midbrain anticonvulsant zone in the superior colliculi is under inhibitory control of efferents from the substantia nigra pars reticulata. Inhibition of the subthalamic nucleus (STN) could release the inhibitory effect of the substantia nigra pars reticulata on the dorsal midbrain anticonvulsant zone and thus activate the latter, raising the seizure threshold. Modulation of the seizure threshold by stimulation of deep brain structures-in particular, of the STN-is a promising future treatment option for patients with pharmacologically intractable epilepsy. Experimental studies supporting the existence of the nigral control of epilepsy system and preliminary results of STN stimulation in animals and humans are reviewed, and alternative mechanisms of seizure suppression by STN stimulation are discussed.

Animals↗

Nocturnal hypoxemia is common in primary pulmonary hypertension.

STUDY OBJECTIVE: Unsuspected sleep-related respiratory events are common in patients with severe pulmonary disease. Sleep in patients with primary pulmonary hypertension (PPH) has not been studied (to our knowledge). The purpose of this study was to measure the prevalence of respiratory disturbances and nocturnal hypoxemia during the sleep of patients with PPH. SETTING: Tertiary-care referral hospital. DESIGN: Retrospective review. PATIENTS: Thirteen patients with PPH. MEASUREMENTS: All patients underwent a single-night comprehensive polysomnogram study. Patients who spent > 10% of the total sleep time with oxygen saturation by pulse oximetry (SpO(2)) at < 90% or who needed oxygen to maintain their SpO(2) level at > 90% were classified as nocturnal desaturators. Analysis was performed to determine which clinical variables (ie, demographics, body mass index, spirometry, diffusion capacity, right heart catheterization pressures, 6-min walk test, arterial blood gas levels, resting and walking SpO(2) levels, and polysomnogram variables) would predict nocturnal desaturation. Statistical significance was considered when p values were < 0.05. RESULTS: Of the 13 patients in the study, 10 (77%) were nocturnal desaturators. All patients had normal apnea indexes, but two had mild elevations of the hypopnea index (< 15 episodes per hour). Nocturnal desaturations occurred independently of apneas or hypopneas. Six patients who did not have O(2) titration during sleep spent > 25% of sleep time with SpO(2) < 90%. The mean (+/- SD) variables that were significantly different between desaturators (10 patients) and nondesaturators (3 patients) were FEV(1) (70.1 +/- 9.1% predicted vs 98.1 +/- 15.1% predicted, respectively; p = 0.002), resting PaO(2) (61.8 +/- 16.1 vs 90.3 +/- 2.3 mm Hg, respectively; p = 0.001), alveolar-arterial oxygen pressure difference (P[A-a]O(2)) (40.5 +/- 20.5 vs 12.2 +/- 7.2 mm Hg, respectively; p = 0.048), resting SpO(2) (91.6 +/- 5.4% vs 98.7 +/- 2.3%, respectively; p = 0.038), and walking SpO(2) (83.8 +/- 9.3% vs 95.3 +/- 1.2%, respectively; p = 0.002). The mean hemoglobin level was higher in the group of nocturnal desaturators than in the group of nondesaturators (10.43 +/- 0.31 vs 13.95 +/- 0.98 g/dL, respectively; p < 0.0001). CONCLUSION: Seventy-seven percent of patients with PPH have significant nocturnal hypoxemia that is unrelated to apneas and hypopneas. Nocturnal desaturation occurs more frequently in patients with higher P(A-a)O(2) values and lower FEV(1) values, resting arterial PaO(2) and SpO(2) values, and walking SpO(2) values.

Adult↗

Seizure outcome after surgery for epilepsy due to malformation of cortical development.

PURPOSE: To explore seizure outcome after surgery for focal epilepsy due to malformation of cortical development (MCD), with focus on the role of MRI. METHODS: Thirty-five patients who had surgery for intractable focal epilepsy due to MCD identified by preoperative MRI and confirmed by histopathologic analysis of resected tissue were studied. Patients were aged 3 months to 47 years (median, 14 years) at the time of surgery. Duration of follow-up was 1 to 7.9 (mean, 3.4) years. RESULTS: At latest follow-up, 17 patients (49%) had Engel Class I outcome with no seizures or auras only; eight patients (23%) had Class II outcome, with rare disabling seizures; seven patients (20%) had worthwhile improvement; and three patients (9%) had no improvement. Seizure-free outcome tended to be more frequent among patients who had complete resection of unilateral MCD (excluding hemimegalencephaly) based on postoperative MRI (7/12; 58%), compared with patients with unilateral MCD who had incomplete resection (3/11; 27%), but the difference was not significant. The frequency of seizure-free outcome did not differ significantly between children (8/14; 57%), adolescents (7/15; 47%) or adults (2/6; 33%); between patients who had daily (12/24; 50%), weekly (4/9; 44%), or monthly (1/2; 50%) seizures preoperatively; between patients who had temporal (2/6; 33%) or extratemporal or multilobar resections (14/28; 50%); or between patients who were (9/16; 56%) or were not (8/19; 42%) studied with subdural electrodes. Results for all analyses were similar when analyzed at latest available follow-up or at 1 year after surgery. CONCLUSIONS: Surgery can offer seizure-free outcome for approximately one half of carefully selected patients with intractable focal epilepsy due to MCD. Complete resection of the MRI-apparent lesion may improve the likelihood for favorable outcome. MRI evidence of hemimegalencephaly or bilateral MCD suggests a low likelihood for postoperative freedom from seizures.

Adolescent↗

Evidence of cingulate motor representation in humans.

A 44-year-old man with a right frontal lobe tumor and intractable seizures underwent subdural grid evaluation before resection. The electrode locations were identified on a three-dimensional surface-reconstructed image of the brain after subdural grid placement. Electrical stimulation of electrodes placed over the right cingulate gyrus revealed evidence of tonic posturing of the left forearm and wrist and tonic extension of the left leg. This finding provides further evidence of a motor area in the cingulate gyrus in humans.

Adult↗

Association between the Epworth sleepiness scale and the multiple sleep latency test in a clinical population.

BACKGROUND: Excessive daytime sleepiness can be evaluated with both subjective and objective tests. OBJECTIVE: To examine the association between Epworth Sleepiness Scale scores and sleep latency on the multiple sleep latency test. DESIGN: Case series. SETTING: Referral sleep disorders center. PATIENTS: 102 consecutive patients evaluated for excessive daytime sleepiness. MEASUREMENTS: Epworth Sleepiness Scale scores and mean sleep latency on the multiple sleep latency test. RESULTS: No significant association was seen between Epworth scores and mean sleep latency (Pearson correlation, -0.17 [95% CI, -0.35 to 0.03]; P = 0.09) (analysis of variance, P = 0.13). The mean Epworth score did not differ in three groups of patients who were defined by mean sleep latency as having normal sleep latency (>10 minutes), moderate sleep latency (5 to 10 minutes), or severe sleep latency (<5 minutes) (analysis of variance, P = 0.13). CONCLUSIONS: No statistically or clinically significant association was seen between Epworth scores and mean sleep latency. The subjective Epworth Sleepiness Scale and the objective multiple sleep latency test may evaluate different, complementary aspects of sleepiness.

Humans↗

A new epileptic seizure classification based exclusively on ictal semiology.

Historically, seizure semiology was the main feature in the differential diagnosis of epileptic syndromes. With the development of clinical EEG, the definition of electroclinical complexes became an essential tool to define epileptic syndromes, particularly focal epileptic syndromes. Modern advances in diagnostic technology, particularly in neuroimaging and molecular biology, now permit better definitions of epileptic syndromes. At the same time detailed studies showed that there does not necessarily exist a one-to-one relationship between epileptic seizures or electroclinical complexes and epileptic syndromes. These developments call for the reintroduction of an epileptic seizure classification based exclusively on clinical semiology, similar to the seizure classifications which were used by neurologists before the introduction of the modern diagnostic methods. This classification of epileptic seizures should always be complemented by an epileptic syndrome classification based on all the available clinical information (clinical history, neurological exam, ictal semiology, EEG, anatomical and functional neuroimaging, etc.). Such an approach is more consistent with mainstream clinical neurology and would avoid the current confusion between the classification of epileptic seizures (which in the International Seizure Classification is actually a classification of electroclinical complexes) and the classification of epileptic syndromes.

Electroencephalography↗

Histopathological correlates of epileptogenicity as expressed by electrocorticographic spiking and seizure frequency.

PURPOSE: To study the correlation between histopathology and epileptogenicity, as measured by seizure frequency and electrocorticography (EcoG), in patients with cortical dysplasia (CD) as compared with control patients with gangliogliomas or gliomas. METHODS: The influence of the histopathological classification and the presence of balloon cells in CD on the frequency and extension of five predefined patterns of ECoG spiking, seizure frequency, age of seizure onset and 6-month postoperative outcome were analyzed in 32 patients with focal epilepsy undergoing presurgical evaluation with chronically implanted subdural electrodes. RESULTS: Comparison of patients with CD, gangliogliomas, and gliomas showed that the seizure frequency was greatest in patients with CD and ECoG spiking and was most extensive in patients with gangliogliomas. The onset of epilepsy was earlier in patients with CD and with gangliogliomas. None of these differences was significant. However, in patients with CD, the presence of balloon cells was associated with significantly greater seizure frequency (p=0.009), and a significantly greater number of electrodes recording continuous frequent spiking (p=0.03). The presence of continuous very frequent spiking correlated with the duration of the epilepsy and the number of seizures recorded during monitoring. No significant correlation was detected between histopathology, seizure frequency, or ECoG activity and postoperative outcome, which was relatively favorable in patients with balloon cells. CONCLUSIONS: CD refers to a variety of histopathological patterns associated with different epileptogenicity. In CD, increased clinical and ECoG epileptogenicity correlates with the presence of balloon cells. This finding confirms that balloon cells should be considered in the histopathological classification of CD. The predefined ECoG were not specific for any of the histopathologies investigated.

Adolescent↗

Semiological seizure classification.

We propose an epileptic seizure classification based exclusively on ictal semiology. In this semiological seizure classification (SSC), seizures are classified as follows: a. Auras are ictal manifestations having sensory, psychosensory, and experiential symptoms. b. Autonomic seizures are seizures in which the main ictal manifestations are objectively documented autonomic alterations. c. "Dialeptic" seizures have as their main ictal manifestations an alteration of consciousness that is independent of ictal EEG manifestations. The new term "dialeptic" seizure has been coined to differentiate this concept from absence seizures (dialeptic seizures with a generalized ictal EEG) and complex partial seizures (dialeptic seizures with a focal ictal EEG). d. Motor seizures are characterized mainly by motor symptoms and are subclassified as simple or complex. Simple motor seizures are characterized by simple, unnatural movements that can be elicited by electrical stimulation of the primary and supplementary motor area (myoclonic, tonic, clonic and tonic-clonic, versive). Complex motor seizures are characterized by complex motor movements that resemble natural movements but that occur in an inappropriate setting ("automatisms"). e. Special seizures include seizures characterized by "negative" features (atonic, astatic, hypomotor, akinetic, and aphasic seizures). The SSC identifies in detail the somatotopic distribution of the ictal semiology as well as the seizure evolution. The advantages of a pure SSC, as opposed to the current classification of the International League Against Epilepsy (ILAE), which is actually a classification of electroclinical syndromes, are discussed.

Electroencephalography↗

Ipsilateral median somatosensory evoked potentials recorded from human somatosensory cortex.

Somatosensory evoked potentials (SEP) to ipsilateral and contralateral median nerve stimulations were recorded from subdural electrode grids over the perirolandic areas in 41 patients with medically refractory focal epilepsies who underwent evaluation for epilepsy surgery. All patients showed clearly defined, high-amplitude contralateral median SEPs. In addition, four patients showed ipsilateral SEPs. Compared with the contralateral SEPs, ipsilateral SEPs were very localized, had a different spatial distribution, were of considerably lower amplitude, had a longer latency (1.2-17.8 ms), did not show an initial negativity, and were markedly attenuated during sleep. Stimulation of the subdural electrodes overlying the sensory hand area was associated with contralateral hand paresthesias, but no ipsilateral hand paresthesias, occurred. It was concluded that subdurally recorded cortical SEPs to ipsilateral stimulation of the median nerve (M) reflect unconscious sensory input from the hand possibly serving fast bimanual hand control. The anatomical pathway of these ipsilateral short-latency MSEPs is not yet known. Transcallosal transmission seems unlikely because of the short delay between the ipsilateral and contralateral responses in selected cases. The infrequent occurrence of ipsilateral subdurally recorded SEPs and their low amplitude and limited distribution suggest that they contribute very little to the short-latency ipsilateral median SEPs recorded on the scalp.

Adolescent↗

Speech and the dominant superior frontal gyrus: correlation of ictal symptoms, EEG, and results of surgical resection.

Two patients with seizures characterized by speech arrest had astrocytoma in the superior frontal gyrus (SFG) of the left hemisphere. Preoperative video EEG monitoring of seizures using subdural electrode arrays showed that comprehension, crude vocalization, and limb and tongue movements were preserved during speech arrest. One patient had difficulty writing during seizures. Ictal EEG onset was localized to the SFG without involvement of Broca's area. Electrical stimulation of SFG electrodes reproduced the speech arrest and writing difficulty. Resection of this region reduced seizures but did not result in lasting speech deficit. Cessation of speech with electrical stimulation of the superior frontal gyrus occurs by interrupting control of muscles required for speaking, which occurs independently of simple 'negative' motor effects. We postulate that functional redundancy is the basis for resection of this region without producing significant speech deficits.

Adult↗