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The authors report their experience utilizing a recently described rapid rate, binaural click and 1000-Hz tone burst modification of the brain stem auditory evoked potentials (BAEP), modified (MBP), in 27 symptomatic patients with non–brain stem compressive space-taking cerebral lesions (22), hydrocephalus (4), and pseudotumor cerebri (1).  Many presented with clinical signs suggestive of increased intracranial pressure (ICP) and focal neurological deficits. The cerebral lesions, mostly large tumors with edema, had very substantial radiological signs of mass effect. Fourteen patients were also studied following surgical decompression. A number of significant changes in the wave V and Vn latency/intensity and less so amplitude/intensity function was found in the 27 patients, compared to normal volunteers, as well as those studied pre- and postoperatively. Similar MBP changes had been noted in normal volunteers placed in a dependent head position. Possible mechanisms to explain these findings are discussed.  The MBP methodology shows promise and further development could make neuro-intensive care unit monitoring practical.

This report deals with a newly described ictal pattern, called the initial ictal slow shift (IS)2. This pattern may be seen in subdural records as the first sign of an ictal event, occurring before the later typical rhythms of a seizure state appear. A positive shift, very similar in appearance from one seizure to another, usually lasted for 1–2 sec, followed by a negativity for 7–9 sec that included the typical rhythmical discharges. At times, a negative shift occurred first, seen up to 15 mV very high in amplitude, for a few seconds before the typical ictal rhythms were seen. Scalp records may also demonstrate slow shifts, and examples are shown of the typical 3/sec bilateral spike and wave (S+W) complexes of absence seizures. A slow shift occasionally appeared 1 sec before the onset of these complexes, but more often a few seconds after the onset. Finally, after the end of the S+W complexes, a positive shift, for as long as 5–6 sec may occur, up to 600 µV in amplitude. These shifts could relate to data showing that patients are not really back to a normal responsiveness for at least 5 sec after the end of the S+W complexes (see Discussion).

Our previous study showed that patients with many spikes in their EEGs generally have uncontrolled seizures and those with no or rare spikes have controlled attacks. However, exceptions do exist, and this study was designed to determine what other aspects in the EEG could lead to the proper prognosis with these exceptions, rather than to an incorrect one. Two groups were assembled: 150 patients with 674 EEGs with controlled seizures and 150 patients with 804 EEGs with uncontrolled attacks. Our data showed that the presence or absence of a slow wave abnormality usually led to a proper prognosis in these exceptional cases. The absence of any slow wave abnormality, but with many spikes was usually associated with controlled attacks and the presence of slowing, especially with delta slow waves, but without spikes, was more often seen in patients with uncontrolled attacks. The change in the number of spikes over time also led to a more accurate prognosis.

This report deals with a patient with intractable seizures, who had 64 subdural electrodes implanted onto the left frontal and temporal cerebral cortex in anticipation of probable seizure surgery. One specific region on the left frontal lobe proved to be the focus for both the interictal spikes and also for the ictal activity. Our goal was to determine what electrical characteristics in the interictal record predicted the ictal episodes. The number of interictal spikes and also the amount of fast activity (15–128/sec) progressively increased before each of the 5 ictal episodes; an analysis showed that the number of spikes and their frequency proved the more significant variable. One other characteristic that changed before the ictal episodes was a great decrease in the interval between spikes as an example of a diminishing variability or increasing periodicity. Thus, the important factors in the interictal record that lead to an ictal event are the number of spikes, the amount of fast activity and the decreasing variability between the spikes.

The goal of this study was to investigate in patients with partial epilepsy the relationship between bilateral spike and wave (BSW) complexes of a generalized epilepsy and the focal spikes of partial epilepsy. For the study 300 patients were collected, all with focal epilepsy on their last hospital visit: 150 were well controlled (C) and 150 were uncontrolled (U), and the number of EEGs was 674 in the C and 804 in the U groups. BSW were seen at some time in 25% of all patients, more often in the U than C patients, especially the irregular 3/sec form. The bilateral complexes at times appeared at the onset of the epilepsy, usually at the same time with focal discharges, mainly from temporal or frontal areas. The U patients showed these complexes at a younger age than the C group and continued to be seen often into the 30s, occasionally into the 60s age group. The other presentation of the BSW was years after the onset of the focal discharges, usually temporal or frontal in location and more often seen in the U than C group. The U group showed spikes, many in number as active foci, more often than the C group. The discussion deals with the possibility that these bilateral spike and wave complexes may represent a reflection of a lowered threshold to a seizure.

The goal of this study was to determine whether the EEG could predict if patients with focal seizures would eventually be uncontrolled (U), more than two seizures per month, or be controlled (C), fewer than two seizures per year. Using these latter criteria, U and C patients were randomly selected from our files, 150 in each of these two groups; 804 EEGs were found in the U and 674 in the C group. Excluded were patients with generalized epilepsy and also the benign epilepsies of childhood. Age was an important factor since patients 5–18 yrs old were more often under good control (C group), and those 21–48 yrs of age were more often under poor control (U group). With rare exceptions, focal spikes and focal slow waves in every area were much more often seen in U patients than C patients. No spikes or rare spikes appeared especially in the controlled patients, and many or very many spikes in the uncontrolled patients, mainly on the first or second EEG. No slow waves or a mild degree of slowing was seen especially in the C patients, while greater degrees of slow wave abnormalities were noted much more often in the U patients.For conditions to identify the C group, the best predictors were no spikes or rare spikes, especially on the first or second EEG, properly identifying two-thirds of the C patients and misidentifying only one-fourth of the U group. To identify the U patients on any EEG, many or very many spikes at any location or frontal spikes correctly designated a U patient in 84%, but incorrectly predicted a C patient as uncontrolled in 29%. For the first or second EEG, these values were 61% and 21%. Thus, the EEG, especially by its first or second record, can predict well the probable future of the uncontrolled patient, so that extraordinary means may be instituted early to avoid a deteriorating condition. When complete EEGs are done with sleep records and the results are quantified, reasonable prediction of eventual outcome can usually occur that is much more timely than waiting over 9 yrs, using only clinical data.

A simultaneous video-EEG on a waking 6-year-old male revealed rapid horizontal and then vertical eye movements and 10 sec later showed ictal rhythms maximal on the occipital areas, quickly spreading to all other areas. A second ictal event during wakefulness was very similar to the first. During sleep interictal discharges were seen from the right frontal-temporal area and one more ictal event was noted. This latter seizure in the NREM sleep record did not show any eye movements, but showed ictal activity on the right frontal-temporal area, which later became generalized. We propose that the interictal discharges on the right frontal-temporal area likely arose from the amygdala, which activated the pontine nuclei responsible for PGO (ponto-geniculo-occipital) spikes and the rapid eye movements seen in our patient. The PGO spikes activated the occipital areas, which then showed clear ictal rhythms to complete the sequence of events. This case demonstrates a sequence of rapid eye movements without ictal patterns, followed by seizure rhythms, but may still be an example of “epileptic nystagmus,” assuming that the eye movements arose from an ictal activation of the deep subcortical portion of the PGO system.