Postprocessing results

Quantitative analysis was performed in 32/45 patients. Hemispheric asymmetry was seen in four: epilepsy was thought to arise from the smaller side in three (34, 35 & 46); localisation was not possible on electroclinical grounds in one (27). SM volume was abnormally low bilaterally in three patients (37, 51 and 55). No other hemispheric volume or callosal area abnormalities were found.

Figure 4.12. Patient 29. Male, 23 at scan, 7 at seizure onset. Fetal cyanosis at birth. Seizures: jerking of right arm and

leg; occasional SGS. Continuous slow and sharp wave activity over L temporal and parietal lobes; ictal EEG unhelpful, postictal activation of left-sided abnormality. Reconstruction

shows attenuation of the left superior temporal gyrus

(arrowed), with possibly some enlargement of the left middle

temporal gyrus.

Figure 4.13. Patient 32. Female, 35 at scan, 7 at seizure onset. Mild left hemiparesis. Typical frontal lobe seizures: brief, frequent, nocturnal, with bilateral arm dystonie

posturing (L>R), grimacing, lower limb stiffening and clonic

left-sided movements. No significant EEG changes. Focal widening of right middle frontal gyrus on surface rendering

(arrowed).

Figure 4.14. Patient 34. Male, 29 at scan, 3 at seizure onset.

Episodes of simple partial status since age 13 : left visual

field obscuration by flashing lights; progression to CPS/SGS. Right occipital ictal discharge; giant phase-locked spikes on photic stimulation. Abnormal right parietal sulcation on reconstruction marked on schematic.

Figure 4.15. Patient 36. Male, 24 at scan, 7 at seizure onset. Frequent nocturnal seizures with extension and dystonie posturing of both arms and bicycling movements of legs. No

significant EEG changes. Reconstruction shows abnormal

sulcation right frontal lobe (arrowed).

Figure 4.16. Patient 41. Female, 44 at scan, 12 at seizure onset.Frequent, brief, nocturnal attacks with stretching of legs and scissor movements and verbalisation. Interictal EEG shows bilateral frontotemporal spikes and sharp waves; ictal recordings unhelpful. Increased complexity over left middle frontal gyrus (marked) on reconstruction.

Figure 4.17. Patient 42. Male, 63 at scan, 40 at onset. Very

frequent (200/day), brief attacks with dazed expression, head

turning and shuffling movements of the left leg; immediate recovery. Frequent sharp waves or sharp-slow wave complexes maximal on frontopolar recording (F3)& bilateral synchronous sharp/slow wave complexes. Ictal EEG unhelpful. Reconstruction confirms atrophy and reveals abnormal gyral pattern in the

left frontal lobe, with a stellate gyral appearance

(outlined).

Figure 4.18. Patient 43. Male, 21 at scan, 12 at seizure onset. Complex partial seizures with extension of left leg;

infrequent nocturnal SGS. Interictal vertex epileptic

activity, field suggestive of horizontal dipole, often seen with small lesions; first ictal changes in R central region, where postictal slow also predominant. Reconstruction shows

small area of abnormal gyral complexity in the right middle frontal gyrus (arrowed).

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Figure 4.19. Patient 44. Male, 18 at scan, 9 at seizure onset. Left hemiatrophy. Frontal lobe seizures: frequent nocturnal complex partial with grimacing and bilateral arms elevation. Interictal EEG shows bilateral frontal parasagittal sharp and slow waves; ictal EEG: generalised attenuation. Reconstruction shows abnormal ring-like gyral configuration right frontal lobe (outlined).

Figure 4.20. Patient 46. Female, 44 at scan, 6 at onset. Complex partial seizures with right arm posturing and left arm automatisms. Predominantly left anterior temporal spikes interictally, with occasional bilaterally synchronous spikes. Ictal EEG unhelpful. Reconstruction shows abnormal gyral configuration left middle frontal gyrus, (ring-like) with central island gyrus (arrowed).

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Figure 4.21. Patient 49. Female, 18 at scan, 3 at onset. Frequent seizures; bilateral arm extension and automatisms. Interictal EEG shows bifrontal spikes more marked on left. Ictal EEG unhelpful. Reconstruction shows gyral abnormality left frontal lobe (outlined).

Figure 4.22. Patient 53. Female, 36 at scan, 8 at onset. Frequent nocturnal attacks; bilateral limb dystonie posturing and late jerking; immediate recovery. Daughter with identical attacks since age 6. Interictally, bilateral slow waves, more marked on left than right; ictal EEG unhelpful. Increased gyral complexity in the left middle frontal gyrus (marked) on reconstruction.

Figure 4.23. Patient 54. Female, 27 at scan, 4 at onset. Frequent seizures: rhythmic jerking of whole body and dystonie posturing of right arm. Interictal EEG shows infrequent abnormality over left frontal region (F3); no ictal changes, postictal left anterior slow wave activity. Reconstruction shows stellate abnormality of disposition of gyri in left frontal lobe (outlined).

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Figure 4.24. Patient 55. Male, 30 at scan, 14 at onset. Born 10 weeks premature; bacterial meningitis at 8/12. Complex partial seizures with blurring of vision, shouting of names, then tonic stiffening of all limbs. Interictal EEG shows sharp-slow wave complexes in both temporal regions; ictal EEG unhelpful. On reconstruction, sulci are shallow in the right

Figure 4.25. Patient 56. Male, 32 at scan, 7 at seizure onset. Complex partial seizures; groaning, grunting, shaking of arms

(R predominantly). After one cluster, right Todd's

paresis. Bursts of high frequency activity right frontal

region (maximal at F4) , less frequent sharp waves or spikes on

left, equipotential at F7 and T3 ; rarely runs of fast activity

in the left inferior frontal regions. On reconstruction, altered gyral patterns both frontal regions (more marked on

right), without clear termination of middle frontal gyrus in

either hemisphere.

Figure 4.26. Patient 59. Male, 48 at scan, 18 at onset. Multiple seizure types; complex partial with epigastric aura, orofacial automatisms, face and eye deviation to the left; or with trembling of left-sided limbs; comlex partial status once a month; secondary generalised seizures every three to six

months. EEG shows posterior right temporal focus. On

reconstruction, abnormal gyrus R middle frontal gyrus

(outlined).

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Figure 4.27. Patient 60. Male, 18 at scan, 6 at onset. Familial frontal lobe epilepsy. Frequent tonic extension of right-sided limbs. No EEG localisation. On reconstruction, gyri of L hemisphere seen to be narrower than those of R hemisphere.

Figure 4.28. Patient 61. Male, 27 at scan, 9 at seizure onset. Previous R temporal lobectomy; seizures returned after 4 years, unchanged semiology: frequent brief attacks with

fidgeting of all limbs and complex automatisms. Depth electrode studies confirmed seizure onset in the right frontal dorsolateral convexity. On reconstruction, abnormal gyral pattern in the inferior margin of the right frontal lobe

Block analysis was not performed in patient 43 because of excessive rotation. In the remaining 31 patients, 16 had structurally abnormal brains as defined (>1 abnormal value of 80/brain). For these 16, the mean number of abnormal values was 4.94. Across all 31, there were a total of 82 abnormal values (expected by chance alone: 6.70). The spatial distribution of these abnormal values is shown in Fig. 4.10 and the distribution in terms of type of block abnormality in Table 4.2. Only 7 of the 16 patients with quantitatively abnormal brains on block analysis have gyral abnormalities on three-dimensional reconstruction.

By definition, no lesions were seen on routine inspection of the two-dimensional images in these patients: in this sense, all the abnormal blocks were "extralesional". If this assessment is related to gyral abnormalities revealed on reconstruction, in the 14 patients with such abnormalities and who had also had block analysis performed, extralesionally abnormal blocks not contiguous with the lesion were seen in

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Analysis of non-homologons block pairs showed 5/32 patients had more than one abnormal pair ratio; two of these (42 & 46) have gyral abnormalities revealed on reconstruction.