DEVELOPMENTAL MEDICINE A N D CHILD NEUROLOGY. 1966, 8

3. - Van Velzer, C. (1964) Presented to the Paediatric Research Society, Post Graduate Medical School.

4. Helmholtz, H. V. (1924) Helmholtz’s Treatise on Physiological Optics. Trans. from 3rd Herman edn,

5. Prechtl, H . R. F. (1958) ‘Directed head turning response and allied movements of the human baby.’

6. Sherrington, C. (1940) Man on his Nature. London: Macmillan. 7. Turkewitz, G., Gordon, E. W.. Birch, H. G. (1965) ‘Head turning in the human neonate: spontaneous

Brain (In press).

ed. by J. C. Southall. Rochester: Optical Society of America.

Behaviour, 13, 212.

patterns.’ J . genet. Psycho/., 107, 143.

ELECTROENCEPHALOGRAPHY IN THE NEONATAL WARD

Now that reliable portable apparatus and suitable electrodes are available, the EEG of newborn babies can be recorded even alongside a cot or incubator, without disturbing any of the special medical or nursing procedures which are sometimes necessary. The interpretation of the records, however, still requires a considerable amount of experience of electroencephalography in this age-group, as well as an understanding of the special clinical problems likely to arise. Since J. ROY SMITH first studied the newborn baby’s EEG in 1937 some useful work has been done on three aspects of this subject.

( I ) Maturation of Spontaneous Cerebral Electrical Activity.-The special features of the EEGS of premature and full-time babies have been discussed by Dr. DREYFUS-BRISAC and her colleagues in many publications since 1955. They have shown how the EEG evolves, from a pattern of intermittent electrical activity, to a complex though more continuous tracing. The EEGS of premature babies show bursts of generalized 0.3-1 c/s waves mixed with some 10-14 c/s and small amplitude faster activities. Some runs of 4-7 c/s activity also occur. These activities alternate with periods when there is no apparent electrical activity at all. There is no obvious periodicity in these changes, and the intermittent activity continues whether the baby is clearly awake or asleep. By 34-36 weeks of gestational age there is a definite difference between the sleeping and waking EEG. When the baby is awake there is irregular activity of mixed frequencies and small amplitude. Prolonged EEG record- ing, with simultaneous records of respiration, body activity, electromyograms and eye movement^,'^-^^ have shown that, from this gestational age, there are two types of EEG when the baby is asleep, and this cyclic type of EEG variation is said not to occur in premature babies under about 36 weeks gestational age.2 The two types of EEG correspond with two different kinds of body activity. In one there is very little body movement and the baby breathes regularly, while the EEG shows discontinuous 2-6 c/s activity of up to 200 micro- volts-the ‘tracP alternant’ described by DREYFUS-BRISAC. I n the other there is more body movement and the respirations are irregular and continuous, while the EEG shows fairly rhythmic activity of smaller amplitude at 4-10 c/s. DREYFUS-BRISAC~ has also shown that the rate of postnatal maturation of the EEG is related to gestational age rather than birth- weight.

(2) EEG Changes in Response to Stimuli.-DREYFUS-BRiSAC and her colleagues3 have described nonspecific changes in the EEG of fulI-time and premature babies subjected to sensory stimuli. The stimulus was followed by an increase or decrease in the amount and amplitude of electrical activity, often accompanied by clinical signs of arousal. These non- specific changes were also noted by ELLINGSON,” ’ in addition to transient waves at the vertex in response to sound. Specific responses confined to the temporal region, however, were not obtained. Evoked responses to sound, using an averaging technique,’. 14, 22 have

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ANNOTATIONS

been recorded from electrodes placed over the central, temporal and frontal regions. These potential changes could be obtained in various stages of wakefulness and sleep, but there were differences in the amplitude and latency of the response components according to the baby's state.

Specific responses to light occur over the occipital region in newborn premature and full- time babies, whether they are awake or asleep, and the wave form, amplitude, distribution and response to repeated stimuli have been fully de~cribed.~- '~ The latency of the response to photic stimulation decreases with increasing gestational age, and this relationship is unaffected by a low Apgar score or the presence of abnormal EEG features. ENGEL'O suggested that these latency measurements might provide another parameter for estimating maturational age at birth. The studies of repetitive photic stimulation by GLASER and LEVY^^ included 60 babies who had suffered some form of perinatal stress. 'Photic following potentials' occurred more often in normal babies 6 hours after birth than earlier, but they occurred less often at this time in the stressed babies.

(3) Abnormal EEG Features.-Many abnormal EEG features have been described in this age group, including generalized or focal spikes and sharp waves, complex wave forms, unusual rhythmic activity, an excess of slow waves, asymmetries between the activities of the two hemispheres, and an apparent absence of electrical activity.l5l7 DREYFUS-BRISAC and MONOD,4v and TIBBLES and P R I T C H A R D ~ ~ are some of the considerable list of contributors to this work. Most of the babies have been studied because of obvious neurological troubles, particularly seizures of various kinds. The gestational age of the babies reported is not always clear, but abnormal EEG features may also be seen in premature babies. DREYFUS- BRISAC and MONOD,' for example, described a baby of 28 weeks' gestational age who had tonic seizures accompanied by EEG changes. In general, marked EEG abnormalities have been found during seizures, although the interseizure record may not show any unusual features. When an abnormal interseizure record is obtained the prognosis is more ~ e r i o u s . ~

ROSEN and SAT RAN^^ looked for abnormal EEG features in repeated records during the first three days of life from 174 babies who were clinically normal but had been exposed to complications of pregnancy or delivery which are known to be associated with perinatal troubles in the baby. Abnormal EEG features were seen, sometimes only transiently, twice as often in these babies as in a much smaller group of normal babies born without any complications.

At present the EEG in the neonatal period is of limited practical value in the management of individual cases, and much more work remains to be done on the subject. In particular there is a need for correlative studies of the various EEG features with clinical, biochemical and cerebral histopathological findings, followed in relation to the development of each child.

RUTH HARRIS

REFERENCES I. Barnet, A. B., Goodwin, R. S. (1965) 'Averaged evoked electroencephalographic responses to clicks

in the human newborn.' Electroenceph. d i n . Neurophysiol., 18, 441. 2. Dreyfus-Brisac, C. ( I 964) 'The electroencephalogram of the premature infant and full-term newborn:

normal and abnormal development of waking and sleeping patterns.' In Neurological and Electro- encephalographic Correlative Studies in Infancy. Ed. by P. Kellaway and 1. Petersen. New York and London: Grune and Stratton, pp. 186-207.

Monod, N. ( 1955) 'Vielle, somrneil et reactivite chez le nouveau-ne a terrne.' In Conditionnement et Reactivite en 6lectroencephalographie, ed. by H. Fischgold and H. Gastaut. Elecfroencepli. din. Neirropliysiof., suppl. 6, 42543 I .

3. -

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DEVELOPMENTAL MEDICINE AND CHILD NEUROLOC; Y . 1 %lb, 8

4. - - (1964) ‘Electroclinical studies of status epilepticus and convulsions in the newborn.’ I n Neurological and Electroencephalographic Correlative Studies in Infancy. Ed. by P. Kellaway and 1. Petersen. New York and London: Grune and Strafton, pp. 250-271.

5 . - Samson-Dollfus, D., Fischgold, H. (1955) ‘L‘activitt electrrque cerebrale du premature et du nouveau-ne.’ Sem. H6p. Paris, 31, 135.

6 . - - Sainte-Anne Dargassies, S. (1955) ‘Vielle, sommeil et reactivite sensorielle chez le premature.’ In Conditionnement et ReactivitC en Eltctroencdphalographie. Electroenceph. clin. Nerrroph.syiol.,

7. Ellingson, R. J. (1958) ‘Electroencephalograms of normal full-term newborns immediately after birth with observations on arousal and visual evoked responses.’ Electroericeph. din. Neurophysiol.. 10, 3 I .

8. - (1960) ‘Cortical electrical responses to visual stimulation in the human infant.’ Electroeticepli. din. Neurophysiol., 12, 663.

9. Ellingson, R. J. (1964) ‘Cerebral electrical responses to auditory and visual stimuli in the infant.’ In Neurological and Electroencephalographic Correlative Studies in Infancy. Ed. by P. Kellaway and 1. Petersen. New York and London: Grune and Stratton, pp. 78-1 14.

10. Engel, R. (1965) ‘Maturational changes and abnormalities i n the newborn electroencephalogram.’ Develop. Med. Child Neurol.. 7, 598-506.

I I . - Butler, B. V. (1963) ‘Appraisal of conceptual age of newborn infants by electroencephalographic

SUPPI. 6,418-24.

methods.’J. Pediat., 63, 386. 12. Glaser. G . H.. Levv. L. L. 11965) ‘Photic following in the EEG of the newborn.’ Anier. J . Dis. Child.,

I _ . 109, ’3 33.

by electroencephalography.’ Laryngoscope, 74, I 3 16.

57, 501.

electroencephalograms of the neonate.’ h1er . J. D ~ J . Child., 76, 634.

- 13. Goldie, L., Van Velzer, C. (1966) ‘Innate sleep rhythms.’ Bruin. ( I n press.) 14. Goodman, W. S., Appleby. S. V., Scott, J. W., Ireland. P. E. (1964) ‘Audiometry i n newborn children

15. Harris, R., Tizard, J. P. M. (1960) ‘The electroencephalograni in neonatal convulsions.’ J . Peclictr.,

16. Hughes, J. G., Ehemann. B., Brown, U. A. (1948) ‘Electroencephalography of the newborn: abnoriiial

17. Imperato, C., Landucci Rubini, L. ( 1958) ’L’elettroencefalagrafia nella clinica del bambino.’ h i Recenti Progr. Pediat. Naples: E.S.I.

18. Monod. N.. Drevfus-Brisac. C. ( 1962) ‘Le trace Daroxvstiaue chez le nouveau-ne.‘ Rev. tieiwol.. 106. 129. 19. Rosen, ‘M. b., Satran, R. (1965) ‘Neonatal clehroencephalography. The EEG of the high risk infant.’

Amer. J. Obstet. Gynec., 92, 247. 20. Smith, J. R. (1937) ‘The electroencephalogram during infancy and childhood.’ Pro(*. Sor. exp. B i d .

Med., 36, 384. 21. Tibbles, J. A. R.. Prichard, J . S . (1965) ‘The prognostic value of the electroencephalogram in neonatal

convulsions.’ Pediatrics, 35, 778. 22. Weitzman, E. D., Fishbein, W., Gaziani. L. (1965) ’Auditory evoked responses obtained from the

scalp electroencephalogram of the full-cerm human neonate during sleep.’ Pedi(i/rirs, 35, 458.

CHTARI’S CEREBELLAR MALFORMATIONS AND THE SPINAL CORD

I N 1891 and 1896 CHIARI*. published excellent accounts of f o u r types of cerebellar mal- formation. Types 111 and I V do not concern us here but for the record Type I l l consists of herniation of the cerebellum into an occipital .meningocele and in Type IV there is hypo- plasia ofthecerebellum. Type I I is now generally known as the Arnold-Chiari malformation. I n Chiari’s Type I malformation there is congenital hydrocephalus, often compensated and non-progressive. with congenital herniation of the cerebellar tonsils through the foramen magnum; there is no gross malformation o f the spinal cord. The Chiari Type I malforma- tion is compatible with normal survival into adult life, but the patients may develop various neurological syndromes, including t h a t due to syringomyelia, in later life. GARUNI:K~ has reported the operative findings in 74 patients with syringomyelia and demonstrated that 68 had a typical Chiari Type 1 deformity. The displaced cerebellar tonsils were usually adherent to the spinal cord, and in at least 30 cases dissection revealed a fibrous membrane over the foramen of Magendie. In all cases there appeared to be partial obstruction to the outflow of cerebrospinal fluid (CSF) from the 4th ventricle, which GARDNER believes to be due t o failure of development of adequate exit foramina. The obstruction is not enough to produce progressive hydrocephalus but enough to prevent the spurt of CSF from the 4th ventricle

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