Bent Stigsby

Regional EEG analysis and regional cerebral blood flow in Alzheimer's and Pick's diseases ☆

Abstract The EEG in 9 Alzheimer and in 4 Pick patients, all confirmed at autopsy were studied. In all Pick patients, and in 6 of the 9 Alzheimer patients, the regional cerebral blood flow (rCBF) was measured in the left hemisphere, using the intra-arterial 133 Xenon clearance technique. Three EEG derivations (F3-C3, T3-T5 and P3-O1) were analysed by means of computer. The EEGs from 13 healthy volunteers matched for age served as controls. The Alzheimer patients showed slowing of the EEG mean frequency in all regions, with increased delta and theta, and decreased alpha and beta activities. In contrast, the alpha activity was preserved parieto-occipitally in the Pick patients, who also showed delta and theta increase, although less so than the Alzheimer patients. The ratio between the mean frequency of the fronto-central and the parieto-occipital regions was increased in the Alzheimer and slightly, but insignificantly, decreased in the Pick patients. The EEG in Picks disease, which is usually considered to be relatively normal even in advanced stages of dementia, was thus clearly different from that of healthy controls. In the Pick patients the regional EEG mean frequency correlated significantly with the corresponding regional flow values. This was not so in the Alzheimer patients, indicating different pathophysiologies in the two disorders. In all patients the EEG mean frequency correlated significantly with the white matter blood flow. Also, the quantity of theta activity and the EEG mean voltage showed significant negative correlations with the regional grey and white matter blood flows, again most striking in the Pick patients.

Electroencephalographic findings during mantra mediation (transcendental meditation). A controlled, quantitative study of experienced meditators

The EEGs of 13 experienced practitioners of transcendental meditation (TM) were recorded for 5 min preceding TM, during 20 min of TM and until 5 min after, as well as during closed-eyed wakefulness, drowsiness, sleep onset and sleep. Thirteen healthy volunteers matched for age served as control subjects. Computer period-amplitude analysis of F3-C3, T3-T5, P3-O1, F4-C4 and P4-O2 epochs of 50--100 sec duration resulted in a frequency and amplitude spectrum (0.5--28.6 c/sec), and the mean frequency and the mean voltage of each EEG lead. The EEG frequency spectra constituted a continuum with increasing theta and delta activity and decreasing alpha activity as the participants tended to fall asleep. The frequency spectrum during TM corresponded to a spectrum situated between that of wakefulness and drowsiness and remained virtually unchanged during the 20 min of meditation. The EEG mean frequency of the TM group was about 1 c/sec slower than that of the control group. Intra- or interhemispheric differences between quantities of EEG activity remained stable during TM, nor did we observe any theta bursts. There was no consistent EEG patter associated with a successful or unsuccessful meditation, nor did the EEGs of two meditators who stated they had felt drowsy during TM show a different pattern.

Miyoshi myopathy in Saudi Arabia: clinical, electrophysiological, histopathological and radiological features

Miyoshi myopathy (MM) is a rare autosomal recessive distal myopathy linked to chromosome 2p12-14 that has not been described in Saudi Arabia. A Saudi family with five siblings aged 3-25 years, an unrelated 18-year-old woman and a 40-year-old man with MM were identified. All patients underwent a neurological examination, serum chemistry, electromyography and MRI of the legs. Four patients underwent a muscle biopsy that was processed for routine enzyme histochemistry and immunocytochemical analyses for dystrophin and adhalin (alpha-sarcoglycan). The two sporadic and two familial cases showed classic findings of MM, including early adult onset, preferential involvement of gastrocnemius muscles, markedly elevated serum creatine kinase levels and dystrophic-appearing muscle without vacuoles. Magnetic resonance imaging revealed selective involvement of the posterior compartment muscles and myoedema by STIR sequences. The remaining three familial cases had elevated serum creatine kinase levels and two also had early myopathic findings by EMG suggestive of MM.

Evoked potential findings in Behçet's disease. Brain-stem auditory, visual, and somatosensory evoked potentials in 44 patients

We studied 54 patients with Behçets disease, 41 males and 13 females, mean age 28 years. Forty-four patients had auditory brain-stem evoked potential (BAEP) recordings, 39 had pattern reversal visual evoked potentials (VEP), 27 had median nerve somatosensory evoked potential (SEP) recordings, and 25 tibial nerve SEPs. BAEPs were abnormal in 16 patients (52%) with neurological manifestations and in 4 (31%) without, because of decreased amplitude of wave V, prolonged I-III or III-V interpeak latencies, or uncertain/absent waves III and/or V. Eleven patients (40%) with neurological symptoms and 3 patients (25%) without, had abnormal VEPs. Absent potentials, decreased amplitude, with or without prolonged P100 latency, were found in 75% of the cases, the rest had prolonged P100 latency only. Median SEPs were abnormal in 8 patients (38%) with neurological manifestations. Four patients (21%) had abnormal tibial SEPs. Decreased amplitude with or without mild slowing in central conduction was the predominant SEP abnormality. SEPs were normal in all patients without neurological symptoms. In total, 84% of patients with, and 38% of patients without, neurological symptoms had abnormalities of one or more EP modality. When used cautiously, EP studies in Behçets disease might be helpful to separate neuro-Behçet from other disorders with similar symptomatology, to disclose subclinical CNS involvement, to evaluate and monitor CNS disease activity, and to provide objective measures of treatment response.

Transcranial magnetic stimulation in Behçet's disease: a cross-sectional and longitudinal study with 44 patients comparing clinical, neuroradiological, somatosensory and brain-stem auditory evoked potential findings

OBJECTIVES To compare neurological involvement in Behçets disease as documented by transcranial magnetic stimulation (TMS) with clinical, neuroradiological, somatosensory (SEP) and auditory evoked potential (BAEP) findings. METHODS Forty-four patients were studied over an 8 year period. Nine patients had follow-up studies done. TMS central motor conduction (CMC) studies to upper and lower limb muscles, brain magnetic resonance imaging (MRI), SEP, and BAEP testing were conducted. RESULTS Thirty-nine patients had CMC slowing, decreased amplitude or absent motor evoked potentials (MEP); 5 of these patients were neurologically normal. Concordance of TMS results, clinical deficits, and MRI findings occurred in 36 of the 39 patients. SEP and BAEP testing proved non-complementary to MEP. Generally, follow-up studies revealed faster CMC and higher MEP amplitude. However, in two patients the CMC time to one target muscle became prolonged with diminished MEP amplitude over a period of 1.5-3 years. CONCLUSIONS TMS can be useful in detecting and quantifying motor tract dysfunction in Behçets disease and provides functional information complementary to imaging studies. TMS is more sensitive than either SEP or BAEP. Our longitudinal studies suggest that TMS studies may be valuable in monitoring disease activity or therapeutic response.

Period-amplitude analysis of the electroencephalogram correlated with liver function in patients with cirrhosis of the liver

Abstract Studies of the activity distribution of the EEG by period-amplitude analysis were made in 40 patients with cirrhosis of the liver, with or without a surgical porto-caval anastomosis, and in 25 control subjects. One hundred seconds of EEG from the two parieto-occipital leads were examined. A quantitative determination of the liver function was made in the patients by the galactose elimination capacity. There was gradual slowing of the EEG when passing from the control subjects to non-shunted cirrhotics and shunted cirrhotics. This was reflected by significant differences of the amount of activity in some of the frequency bands and by a decrease of the dominant EEG frequency. Amplitude measurements yielded little useful information. There was a statistically significant, although weak, positive correlation between the dominant EEG frequency and the galactose elimination capacity in the non-shunted patients and in both patient groups considered together, while the correlation was not significant in the shunted patients alone.

Teaching NeuroImages: Harlequin syndrome caused by lesion of sympathetic regulatory neurons

A 48-year-old woman presented with a 6-year history of recurrent episodes of exertional asymmetric flushing of the face and head. After exercise, she observed a distinct line of demarcation between the left half of her face, which was red, and the right half, which retained its normal …

Dementias (Alzheimer's and Pick's Disease): Dysfunctional and Structural Changes

ABSTRACT.The clinical symptomatology, neuropathological characteristics, neurotransmitter deficiencies, and genetical aspects of Alzheimers disease are briefly reviewed. In Alzheimers disease, a diffuse cortical atrophy is present whereas the atrophy in Picks disease is circumscript and restricted to the frontal and temporal lobes.Profound neurotransmitter deficits, especially in the cholinergic system has been demonstrated in Alzheimers disease. Recent attempts to reverse the cholinergic deficit have been encouraging.The cerebral blood flow is decreased in both diseases but with different regional flow patterns. Generally, Alzheimers disease is accompanied by slowly progressing diffuse EEG abnormalities. In Picks disease, however, the EEG often appears to be normal on visual inspection, though computer analysis may reveal significant deviations from normality.

Intraoperative direct cortical stimulation motor evoked potentials: Stimulus parameter recommendations based on rheobase and chronaxie

OBJECTIVE To determine optimal interstimulus interval (ISI) and pulse duration (D) for direct cortical stimulation (DCS) motor evoked potentials (MEPs) based on rheobase and chronaxie derived with two techniques. METHODS In 20 patients under propofol/remifentanil anesthesia, 5-pulse DCS thenar MEP rheobase and chronaxie with 2, 3, 4 and 5ms ISI were measured by linear regression of five charge thresholds at 0.05, 0.1, 0.2, 0.5 and 1msD, and estimated from two charge thresholds at 0.1 and 1msD using simple arithmetic. Optimal parameters were defined by minimum threshold energy: the ISI with lowest rheobase2×chronaxie, and D at its chronaxie. Near-optimal was defined as threshold energy <25% above minimum. RESULTS The optimal ISI was 3 or 4 (n=7 each), 2 (n=4), or 5ms (n=2), but only 4ms was always either optimal or near-optimal. The optimal D was ∼0.2 (n=12), ∼0.1 (n=7) or ∼0.3ms (n=1). Two-point estimates closely approximated five-point measurements. CONCLUSIONS Optimal ISI/D varies, with 4ms/0.2ms being most consistently optimal or near-optimal. Two-point estimation is sufficiently accurate. SIGNIFICANCE The results endorse 4ms ISI and 0.2msD for general use. Two-point estimation could enable quick individual optimization.