Erna L. Gibbs

Extreme Spindles: Correlation of Electroencephalographic Sleep Pattern with Mental Retardation

An electroencephalographic abnormality is described which is relatively common among children below 12 years of age who are mentally retarded. This pattern consists of exaggerated sleep spindles, which are of higher voltage and more continuously present than in normal persons, and it correlates specifically with mental retardation and not with epilepsy or cerebral palsy.

Fourteen and six per second positive spikes

Abstract The literature daaling with the 14 and 6/sec positive spike pattern is reviewed. This electrographic entity is common and is considared of dafinite diagnostic significance. Incidance, relationship with age and clinical EEG correlations, which were obtained from the analysis of over 5,000 cases in which this pattern was found, are illustrated and discussed.

Clinical Correlates of Various Types of Extreme Spindles

At the meeting of the Eastern Association of Electroencephalographers, held at St. Donat, Quebec, March 27-30, 1952, Dr. Peter Kellaway read a report which was abstracted in the Journal of Electroencephalography and Clinical Neurophysiology (1) . The first paragraph reads as follows: An apparent disturbance of the spindle mechanism in which the spindles occur almost continuously during sleep and may persist following arousal is described in certain cerebral disorders of infants. The common occurrence of this type of abnormality in children with cerebral palsy is pointed out and the possible relationship to damage of the reticular system of the brain stem is suggested. Neither of the present authors attended this meeting and we are sorry that we did not become aware of this abstract until recently. Winfield, Hughes and Sayle published an article dealing with high voltage sleep spindles in patients with cerebral palsy ( 2 ) , and referred to a personal communication from Dr. Kellaway, but not to his abstract. In a recent telephone conversation, Dr. Kellaway said that he had not published anything further on this subject. Ten years after Dr. Kellaway’s report, we published in Science, a brief note on the relationship between extreme spindles and mental retardation ( 3 ) and we regrettably failed to refer to Kellaway’s abstract or to the article by Winfield, Hughes and Sayle. A few years later, in Volume 3 of our Atlas of Electroencephalography (4), and in C. H. Carter’s Medical Aspects of Mental Retardation (5), we reported more extensively on the correlation between extreme spindles and mental retardation and in both of these works, though Kellaway’s abstract remained unnoticed, we did refer to the article by Winfield, et al. Through the kindness of Dr. Etienne Matthys, it was possible to arrange with Dr. H. Steffens to conduct a search of the world literature for the years 1960-1972, using the computerized index of the Royal Library in Brussels. Only one other somewhat relevant report was found, that of Gross and Schulte (6) ; they reported an excess of spindle activity in children with phenylketonuria. Four other articles that had promising titles (7-10) turned out to be non-relevant. Correspondence with leading investigators in America and abroad did not enlighten us as to the reason why extreme spindles have not been more generally recognized as a significant abnormality. The present study was undertaken to determine whether various types of extreme spindles differ as regards their clincial correlates.

How Much Do Sleep Recordings Contribute to the Detection of Seizure Activity

For the past 28 years my wife and I have been recording EEGs both awake and asleep. We started doing this because we found that although focal and diffuse slowing usually disappear in sleep, seizure discharges usually become more numerous and certain types of seizure discharges appear in sleep that are almost never seen awake. It was in 1944 also, that my wife and I became exclusive monopolarists. For the previous 10 years we had used both bipolar and common reference leads. We had become increasingly aware that both montages showed the same thing and that the monopolar view gave a simpler picture. With monopolar recording, voltages were higher, wave forms more consistent and electrical sign was immediately obvious. Among patients with clinically diagnosable epilepsy, approximately one third show seizure activity in the awake recording, but in sleep and drowsiness, 80-90 per cent show seizure activity (1). We have reviewed our case material, collected since 1944, to see how great a contribution sleep recordings make to the detection of various types of seizure discharges. The young lady shown in Fig. 1 is our research assistant. She helped get together all our cases that had an anterior temporal focus of seizure activity. This focus is called a psychomotor type of focus because it is commonly associated with trance-like attacks and confusional episodes. The data concerning each case was put onto a McBee marginal punchcard and the cards were sorted to see how many cases had anterior temporal spiking awake only, how many asleep only and how

Electroencephalogram in Hydrocephalus

Previous reports regarding electroencephalograms in hydrocephalus have been based almost exclusively on awake recordings. The chief exception is an article published by Fois, Gibbs and Gibbs’, in which they reported that a high percentage (66%) of these patients showed bilaterally independent or asynchronous sleep patterns. In previous reports of the waking activity Kreezer2 reported high voltage alpha waves and the Gibbs3 mixed fast and slow activity. Pampiglione and Laurence4 found no correlation between the size of the head, thinness of the pallium and any particular electroencephalographic pattern. In two patients they found no marked changes in the electroencephalogram when the intraventricular pressure had been lowered to one-half of its original value by ventricular drainage. They noted marked asymmetry in the activity of the two cerebral hemispheres, especially in cases of cisternal block. Other references to the literature prior to 1964 are cited in Vol. 3 of the Gibbs‘ Atlas5. Three recent studies were not published in full but only as abstracts. Sternberg et a1.6 studied 50 cases of hydrocephalus and reported four different types of abnormality: (1) increased voltage production, (2) slow waves or spike and wave discharges, either asymmetrical or focal, (3) diffuse abnormality, (4) unilateral depression of amplitude. Only the last mentioned correlated with particular clinical features of the case. Of eighteen patients with shunts, Law and Niedermeyer’ found only one who had a normal EEG. Seizure discharges were present in twenty-five patients without shunts; three were normal. Forster and Pornpino8 studied thirty-one hydrocephalics; eighteen were normal and thirteen were abnormal. In several cases after shunting the EEG showed changes whichwere of some prognostic value. Because of the increased interest in the neurosurgical treatment of hydrocephalus, we decided to re-evaluate the electroencephalogram in this condition, with particular emphasis on the information contributed by sleep recordings, largely disregarded by other investigators.

Clinical Correlates and Prognostic Significance of Various Types of Mid-Temporal Spike Focus

That the wiggly lines forming the electroencephalogram mean something has not always been granted. Their clinical significance or lack of it is by no means self-evident. What they mean cannot be determined by polling the electroencephalographers of any one country or of the entire world. The question of what is normal and what is abnormal can be settled scientifically only by finding out what features of the electroencephalogram are associated with and what are unassociated with disease states. From our earliest electroencephalographic studies (1) onward, we sought to find electroencephalographic abnormalities correlating with various clinical disturbances. The 3 per second spike-and-wave of petit mal was the first to come to our attention (1), the grand mal type of discharge was next (2) and the generalized discharges that occur during clinical seizures of the psychomotor type was recognized later (3). Still later we became aware that there are important differences between the 3 per second spikeand-wave and the 2 per second spike-andwave (4). As time went on our attention was drawn to other significant patterns (5) (6). Eventually we distinguished 46 different electroencephalographic abnormalities that are associated with different incidences of various symptoms, that have different age characteristics and that differ as regards their etiologies (7). For reasons that are hard to explain. some of the most striking correlations and the most useful distinctions remain unrecognized by leading authorities. Even though there is a marked difference between the clinical correlates of a spike focus in the mid-temporal area and one in the anterior temporal area, the distinction is more often

“Flat” electroencephalograms in physiological decortication and hemispherectomy (recordings awake and asleep)

Abstract Four patients with severe bilateral cortical damage were chosen for study because they had bilateral flat (almost isoelectric) electroencephalograms. In two of these patients the damage was presumably due to an anesthesia accident, in one to encephalitis and in one to severe prolonged hypo-glycemia. Two cases on whom hemispherectomies were performed were chosen for study because they showed post-surgically a flattening of activity on the operated side while the unoperated side retained a normal voltage. In all these cases sleep produced no significant change in the flat electroencephalogram; sleep was distinguised in the flat EEG only by dropping out of superimposed muscle potentials. In cases where a relatively isoelectric state is the result of destruction or absence of cortical tissue the same extreme hypopotentia continues in sleep.

Tumor Sites in Cases of Brain Tumor with Mitten Patterns in the Electroencephalogram

A letter from Ilmar Sulg in Helsingborg asked an interesting question, “What is the incidence of mitten patterns among persons with brain tumors?” As those familiar with our previous work know, mitten patterns (Fig. l ) , occur in moderately deep sleep in approximately 1.3 percent of a random sample of adult control subjects (1) (2) and in a much higher percentage of psychotic patients (Fig. 2) , the highest incidence being among psychotic epileptics (42 percent). Struve and his colleagues (3, 4, 5) have shown that mittens are far more common among the reactive type of schizophrenics (33-73 percent) than among the process type (7 percent) and recently these authors have pointed out that mittens are almost never found in persons below 14 years of age (6). Obviously age is a controlling factor and Sulg’s question cannot be answered without specifying the age range to which the percentage incidence of patients with brain tumors and mittens applies. A series of 261 consecutive cases of brain tumor with sleep recordings, all patients being over 14 years of age, yielded 20 cases with mitten patterns, i.e., 7.7 percent, which is an incidence approximately 6 times greater than in a random sample of control subjects of the same age (1.3) percent) (1) (2 ) . This suggests that brain tumors can produce mitten patterns (since a casual relation between mittens and brain tumors seems illogical), A second question naturally follows Sulg’s first question, “Where were the brain tumors located that were associated with mitten patterns?” The answer is set forth in Table 1 Tumors in certain locations are common and in other locations rare, and Figure 3 shows the percentage of cases with a tumor in a given location that were associated with mittens.

Clinical Significance of 14 and 6 Per Second Positive Spikes in the Electroencephalograms of Patients Over 29 Years of Age

Fourteen and 6 per second positive spikes are so common in the electroencephalograms of school-age children that many electroencephalographers have concluded that they are normal. They have been reported as occurring in 15-50 percent of control subjects 4-19 years of age (1-6). Among asymptomatic adults over 29 years of age this pattern is rare; the incidence was only 0.3 percent in 344 control subjects over 29 years of age (6 ) . We thought it would be of interest to study the clinical correlates of 14 and 6 per second positive spikes in this older age group. Among 3,452 consecutive patients over 29 years of age who were referred to our private office for electroencephalographic study, 207, or 6 percent had 14 and 6 per second positive spikes (Table 1 ) . This percentage is not large, but if 14 and 6 per second positive spiking is normal for mature adults, it seems strange that it occurred 20 times more often among patients than among control subjects. Among our patients over 29 years of age, there were 46 who had sustained head traumas but had no symptoms; of these asympto-

Amphetamine Induced Sleep in Children With Extreme Spindles

Extreme spindles, i.e., high voltage moreor-less continuous sleep spindles in the electroencephalogram, were originally described by Kellaway in 1952 (I), and later reported by Winfield et al. in 1955 (2 ) . Their association with mental retardation has been emphasized by the present authors (3-6). They are found in a special, highly organic type of mental retardation, usually in association with neurological defects and deficits. They are most commonly seen in children 2-9 years of age ( 6 ) . Extreme spindles are in general a sleep pattern, but in some cases they are evident both awake and asleep. In our material all patients with spindles awake and extreme spindles asleep were mentally retarded (6 ) . Kellaway ( 1) , suggested that extreme spindles are evidence of damage to or disorder in the reticular formation. Animal studies indicate normal sleep spindles are produced by the intralaminar nuclei of the thalamus ( 7 ) . It seemed possible to us that some type of injury or disorder in the sleep producing structures in the diencephalon might be responsible for the intellectual subnormality of persons with extreme spindles. If so, the subnormality of such persons might be due to their inability to become fully “awake.” We wondered whether, if these patients could be alerted, they would become more intelligent. Seven mentally retarded children were selected with spindle-like waves in their waking e!ectroencephalograms and extreme spindles in sleep. An attempt was made to “awaken” them with intramuscular injections of amphetamine (Benzedrine). The doses used were from 10-20 mg. administered intramuscularly. In all cases instead of reacting with the usual excitement, these children reacted as though they had been given a powerful sedative; they went to sleep (Figures 1 and 2 ) . From this amphetamine induced sleep, they were as difficult to arouse as from a sleep induced with Seconal or chloral hydrate, two drugs which were used to induce sleep in these same children at doses no different from those employed routinely to obtain sleep recordings.