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H H Morris

Publications and source records attributed to H H Morris.

At least 37 records · Page 2Linked to original sources
PubMed1996

Reliability and comparison of RPE during variable and constant exercise protocols performed by older women.

The purposes of this study were to assess if women 60 to 75 years of age perceived a series of exercise intensities differently from selected intensities in that series and to determine if a particular intensity was perceived more reliably. Twenty-four women (65 +/- 3.8 yr) completed a walking VO2max treadmill test. Subjects were either assigned to a variable, randomly ordered exercise protocol (GP1) or to one of three constant exercise protocols (Gps2-4). Each subject performed relative exercise intensities of 30, 50, and 70% of peak VO2 for three 5 min work bouts over 3 test days. Differences in RPE (p < 0.05) were found between each intensity and between the same intensities from both protocols. Women in GP1 rated exercise higher than women who exercised at a constant exercise intensity (p < 0.05). Intraclass correlation coefficients indicated that the exercise intensity of 50% of maximum was more reliable regardless of the protocol (Gp1: R = 0.97, Gp3: r = 0.94). When the RPE-HR correlation coefficients were transformed into a log scale, neither protocol had a stronger association (p > 0.05) between RPE-HR. It was concluded that older women should be given a range of exercise intensities that include the 50% relative exercise intensity as a perceptual marker in order to reach a reliable rate of exertion.

Aged↗
PubMed1996

Outcome of temporal lobe epilepsy surgery predicted by statistical parametric PET imaging.

UNLABELLED: PET is useful in the presurgical evaluation of temporal lobe epilepsy. The purpose of this retrospective study is to assess the clinical use of statistical parametric imaging in predicting surgical outcome. METHODS: Interictal 18FDG-PET scans in 17 patients with surgically-treated temporal lobe epilepsy (Group A-13 seizure-free, group B = 4 not seizure-free at 6 mo) were transformed into statistical parametric imaging, with each pixel representing a z-score value by using the mean and s.d. of count distribution in each individual patient, for both visual and quantitative analysis. RESULTS: Mean z-scores were significantly more negative in anterolateral (AL) and mesial (M) regions on the operated side than the nonoperated side in group A (AL: p < 0.00005, M: p = 0.0097), but not in group B (AL: p = 0.46, M: p = 0.08). Statistical parametric imaging correctly lateralized 16 out of 17 patients. Only the AL region, however, was significant in predicting surgical outcome (F = 29.03, p < 0.00005). Using a cut-off z-score value of -1.5, statistical parametric imaging correctly classified 92% of temporal lobes from group A and 88% of those from Group B. CONCLUSION: The preliminary results indicate that statistical parametric imaging provides both clinically useful information for lateralization in temporal lobe epilepsy and a reliable predictive indicator of clinical outcome following surgical treatment.

Adult↗
PubMed1995

The value of PET scan (and MRI and Wada test) in patients with bitemporal epileptiform abnormalities.

BACKGROUND: Lateralization remains difficult in patients with bitemporal epileptiform abnormalities. OBJECTIVE: To evaluate the reliability of the interictal fluorodeoxyglucose F18-positron emission tomographic (PET) scan in this setting. METHODS: We analyzed PET scan findings in 25 patients who required bilateral depth electrodes for lateralization of temporal lobe epilepsy. The contribution of magnetic resonance imaging and the intracarotid amobarbital procedure was also analyzed. RESULTS: Positron emission tomographic scan revealed lateralized hypometabolism in 15 patients. This was in agreement with the depth evaluation in 10 cases (67%). In five cases (33%), the PET and depth findings were in disagreement, with no predominant side of seizure origin by depth electroencephalography (EEG) in four cases and PET lateralization opposite to depth findings in one case. In 10 of the 25 patients, PET scans could not lateralize hypometabolism to one temporal lobe, of which six were confirmed by depth EEG not to have a predominant side of seizure onset. The overall sensitivity of PET for concordant lateralized seizure onset was 67%. Ten of 14 patients who underwent a lobectomy had a successful outcome, including three of four patients whose temporal lobe epilepsy was lateralized by depth EEG but not by PET. One patient had PET lateralization opposite to the depth EEG and side of surgery and failed to improve. CONCLUSIONS: In this highly selected group of patients, the lateralizing value of PET and magnetic resonance imaging was somewhat diminished, and the intracarotid amobarbital procedure was not found useful for lateralization. Positron emission tomography and magnetic resonance imaging, when pointing to the side opposite depth EEG, may indicate a poor prognosis.

Adult↗
PubMed1995

Movement-related potentials associated with bilateral simultaneous and unilateral movements recorded from human supplementary motor area.

To clarify the differences of movement-related potentials (MRPs) among ipsilateral, contralateral and simultaneous bilateral movements, MRPs with finger, thumb or foot movements were recorded from subdural electrodes chronically implanted on the supplementary motor area (SMA) in 3 patients, and also from the primary sensorimotor area in two of them being evaluated for epilepsy surgery. As a result: (1) SMA generated clear pre-movement potentials regardless of the type of movement. Its amplitude was almost identical between contralateral and bilateral movements except for the motor potential (MP). The pre-movement potentials associated with ipsilateral movements were relatively smaller than those with contralateral or bilateral movements. (2) The primary sensorimotor area generated clear pre-movement potentials in contralateral and bilateral movements with similar amplitude. With ipsilateral hand movements, however, only a small Bereitschaftspotential (BP) and no negative slope (NS') or MP was seen, and ipsilateral foot movements were not preceded by any BP. It is, therefore, most likely that, as far as the preparation for simple voluntary self-paced movement is concerned, the SMA plays an equally important role in unilateral and bilateral movements, whereas the primary sensorimotor area is involved predominantly in the preparation of contralateral movements.

Adult↗
PubMed1995

Generator locations of movement-related potentials with tongue protrusions and vocalizations: subdural recording in human.

Movement-related potentials (MRPs) associated with tongue protrusions and vocalizations were recorded from chronically implanted subdural electrodes over the lower perirolandic area in 7 patients being evaluated for epilepsy surgery. In 3 patients, tongue protrusions elicited a clearly defined, well localized slow negative Bereitschaftspotential (BP) at the motor tongue area, and a positive BP at the sensory tongue area. At the motor tongue area the negative BP was followed by a negative slope (NS') and a motor potential (MP), and at the sensory tongue area the positive BP and a positive reafferent potential (RAP) were seen but no NS' and MP could be identified. In the other 4 patients, tongue protrusions elicited positive BP, NS' and MP at the motor and sensory tongue area, and positive RAP at the sensory area. It was concluded that BPs, NS' and MPs are mainly generated in the motor cortex involving the crown as well as the anterior bank of the central fissure. The sensory cortex (areas 3a and 3b) also participated in the generation of BPs but to a lesser degree. Different degree of involvement of these multiple generators most likely explains the interindividual variability of polarity and distribution of the MRPs. RAPs most likely arise from primary sensory areas 1 and 2. Brain potentials were also recorded at the motor (2 patients) and sensory (2 patients) language areas, but no specific language-related potentials could be identified. Evoked potentials to lip stimulation were investigated in 4 patients. In 3 patients, the responses at the sensory tongue area (P16, N21 and P30) had the same latency but opposite polarity to those at the motor tongue area. In the other patient, the responses (P16, N21 and P30) at the motor and sensory tongue areas were of the same polarity. The MRPs to tongue protrusions in those 4 patients revealed the same polarity relationship between the pre- and postcentral potentials. However, the maximal amplitude of evoked potentials and MRPs was seen at almost the same electrodes, suggesting that the main generators for these MRPs and evoked potentials must be located at contiguous areas in the anterior and posterior bank, respectively, of the central fissure.

Adolescent↗
PubMed1995

Frontal lobe seizures: electroclinical syndromes.

To define further the electroclinical manifestations of frontal lobe epilepsy (FLE), we studied 150 seizures manifested by 24 patients; 18 patients had subdural electrode arrays (SEA). The findings in these patients clearly overlapped presumably reflecting the interconnections between functionally related frontal zones; yet the manner in which the symptoms clustered and the sequence in which they occurred generally indicated the anatomic site of the epileptogenic zone. We divided the patients into three major groups: (a) those with supplementary motor seizures, (b) those with focal motor seizures, and (c) those with complex partial seizures (CPS, psychomotor seizures). Supplementary motor seizures began with tonic posturing of the extremities. Focal motor seizures generally began with conscious contralateral version or unilateral clonic focal motor activity; tonic posturing was noted only late in the seizure. CPS (psychomotor) began with unresponsiveness at onset, followed by staring or unconscious contraversion. We compared frontal lobe seizures with temporal lobe seizures reported previously; oral-alimentary automatisms, repetitive hand movements, or looking around, were more common in temporal lobe seizures, whereas tonic posturing and bicycling movements were more common in frontal lobe psychomotor seizures.

Adolescent↗
PubMed1995

Effects of auditory radio interference on a fine, continuous, open motor skill.

The effects of human speech on a fine, continuous, and open motor skill were examined. A tape of auditory human radio traffic was injected into a tank gunnery simulator during each training session for 4 wk. of training for 3 hr. a week. The dependent variables were identification time, fire time, kill time, systems errors, and acquisition errors. These were measured by the Unit Conduct Of Fire Trainer (UCOFT). The interference was interjected into the UCOFT Tank Table VIII gunnery test. A Solomon four-group design was used. A 2 x 2 analysis of variance was used to assess whether interference gunnery training resulted in improvements in interference posttest scores. During the first three weeks of training, the interference group committed 106% more systems errors and 75% more acquisition errors than the standard group. The interference training condition was associated with a significant improvement from pre- to posttest of 44% in over-all UCOFT scores; however, when examined on the posttest the standard training did not improve performance significantly over the same period. It was concluded that auditory radio interference degrades performance of this fine, continuous, open motor skill, and interference training appears to abate the effects of this degradation.

Attention↗
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↗
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

Comparison of scalp electroencephalogram with subdural electrocorticogram recordings and functional mapping in frontal lobe epilepsy.

We compared the findings of scalp electroencephalogram with subdural electrode array (SEA) recordings in 19 patients with refractory frontal lobe epilepsy. Prolonged scalp interictal recordings localized the epileptogenic zone in 12 patients; seven had no interictal sharp waves. The SEAs showed multifocal interictal sharp waves in all patients. Seven patients with localized seizure onset on scalp recording showed extensive ictal onset on the SEA recording. Five patients with lateralized seizure onset to one hemisphere on scalp recording were found to have ictal onset on SEA restricted to a smaller area. Because of the large epileptogenic zone found on SEA recordings, a complete resection was possible in only five (33%) of the 15 patients who had resections. Eight (53%) of the 15 patients benefited from surgery (mean follow-up, 4.6 years). The SEAs also allowed functional localization in most patients. From these data, we suggest that a localizing scalp electroencephalogram in patients with frontal lobe epilepsy may be misleading because SEA recordings show larger epileptogenic zones than anticipated. Furthermore, we postulate that the larger extensive epileptogenic zone may account for the poorer surgical outcome in patients with frontal lobe epilepsy compared with patients with temporal lobe epilepsy.

Adolescent↗
PubMed1993

Effect of cranial irradiation on seizure frequency in adults with low-grade astrocytoma and medically intractable epilepsy.

We report the effect of cranial irradiation on seizure frequency in five adults with unresected (biopsy-proven) cerebral hemisphere low-grade astrocytoma and medically intractable epilepsy. Seizures were refractory to standard antiepileptic drugs for 7 months to 27 years. Treatment with 5,400 cGy to 6,120 cGy focal radiation reduced seizure frequency by more than 90% in three patients (one of whom became seizure-free) and by more than 75% (but less than 90%) in one patient. One patient had no response. Brain CT or MRI showed a partial tumor response to radiation in three of the four patients with reduced seizure frequency. In three patients, the reduced seizure frequency continued to the most recent follow-up of 1 to 1.5 years. In the patient who became seizure-free, seizures recurred at 8.2 years and were associated with tumor progression. Irradiation can reduce seizure frequency in some patients with unresected cerebral hemisphere low-grade astrocytoma and medically intractable epilepsy.

Adult↗
PubMed1992

Hair loss after prolonged EEG/video monitoring.

We report five patients who experienced delayed patchy hair loss after prolonged EEG monitoring. The location of the patches corresponded to the electrode sites in four. The hair loss was temporary and most probably was due to traumatic noncicatricial alopecia. The frequency of hair loss was approximately 2% of monitored patients.

Adult↗
PubMed1991

Etiologic factors for unitemporal vs bitemporal epileptiform discharges.

We compared the etiologic factors and clinical characteristics of 30 patients with unitemporal vs those of 30 patients with bitemporal independent (minimum 20% from one side) interictal epileptiform discharges on extracranial electroencephalograms. Febrile seizures occurred significantly more frequently in the unitemporal (40%) than in the bitemporal (17%) group. Mass lesions were more common in the bitemporal group, and seven of 10 patients with mass lesions showed bitemporal interictal epileptiform discharges. There were no statistically significant differences in age at onset, frequency of seizures, duration of epilepsy, and history of central nervous system infection or trauma between the two groups. A history of febrile seizures or central nervous system infection that may be expected to cause diffuse cerebral injury does not appear to be the major factor predisposing to the development of bitemporal interictal epileptiform discharges.

Adolescent↗
PubMed1991

Stimulus intensity and experimental design effects on motor response processing.

Experimental design effects and range effects may have influenced previous studies on motor response processing (Grice & Hunter, 1964; Grice, Nullmeyer, & Schnizlein, 1979; Poulton, 1973). This investigation was conducted concurrently with two experiments. First, Erlebacher's (1977) more powerful analysis of variance (ANOVA) model, which allows for the testing of the independent variable (stimulus intensity effect), the experimental design effect (between-subjects [BS] vs. within-subjects [WS]), and the important interaction between independent variable and experimental design was utilized to clarify if the nature of the experimental design (BS, WS) biases motor response processing. Second, Erlebacher's (1977) ANOVA model was used to determine if motor response processing was affected by stimulus intensity and experimental design when different ranges of auditory stimuli were compared. Results indicate motor response processing was inversely affected by increasing stimulus intensity. Experimental design effects and range effects did not appear to bias motor response processing. We conclude stimulus intensity effects on motor response processing appear to be the result of true neuromotor functioning and not artifacts of experimental design or of range effects.

Acoustic Stimulation↗