Journal ofNeurology, Neurosurgery, and Psychiatry 1991;54:633-638 633 Anterograde amnesia with fornix damage J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.54.7.633 on 1 July 1991. Downloaded from following removal of IIIrd ventricle colloid cyst John R Hodges, Katherine Carpenter Abstract was normal. A CT scan revealed a typical high Two patients developed anterograde density non-enhancing colloid cyst situated in amnesia following the apparently the anterior part of the IlIrd ventricle with a uncomplicated transcallosal-trans- mild degree of obstructive hydrocephalus. ventricular removal of a colloid cyst. Surgery was performed in July 1985. A Damage to the fornical columns was transcallosal approach to the left lateral ven- demonstrated on CT and MRI scans, tricle was used. A 2 cm incision was made in whilst other memory related structures the corpus callosum. The pericallosal arteries were entirely normal. Longitudinal were identified and spared. A typical tense neuropsychological evaluation, over 12- colloid cyst was identified embedded in the 24 months, has revealed a very similar septum pellucidum which was opened. The pattern of deficit in the two cases: verbal cyst was then removed via the left foramen of memory has remained persistently Munro without apparent damage to the for- impaired whilst nonverbal anterograde nices. There were no operative complications memory has improved to some degree. and the patient's recovery in the immediate Formal tests of remote public (famous post-operative period was uneventful. faces and events) and personal Upon recovery, it was immediately autobiographical memory have suppor- apparent that she had developed an amnesic ted the clinical impression that neither syndrome with anterograde memory impair- patient has a temporally extensive ment so that she was unable to retain simple retrograde amnesia. These findings verbal material (for example, name and address the role of the fornix, and the address) for more than a few minutes and was dissociation of memory processes in disorientated in time. The retrograde amnesia humans. initially covered the last 12 months. For in- stance, she was unable to recall the operation, preceding illness or family events of the past The issues addressed in this paper are year. Over the next few months, however, the threefold. Firstly, the finding of a clinically retrograde amnesia gradually decreased to significant amnesic syndrome in two patients approximately four weeks in duration. following the apparently uncomplicated trans- Detailed and repeated informal assessment of callosal removal of colloid cysts from the remote memory, for both personal and public http://jnnp.bmj.com/ IlIrd ventricle has obvious practical implica- events, from the past two decades has shown tions for the management of such cases.'2 consistently excellent performance. Secondly, the site of pathology has relevance Although there has been no improvement in to the continuing controversy concerning the the degree of anterograde memory impair- role of the fornix in human memory.3 Thirdly, ment during the two years since her surgery the pattern of memory deficit, with partial she has adjusted well to the handicap by the recovery of non-verbal anterograde memory extensive use of mnemonic devices, and on September 23, 2021 by guest. Protected copyright. and the absence of appreciable retrograde retains good insight into her memory amnesia in either case, addresses the issue of capacities. In 1986 she returned to work at her the dissociation of memory processes, parti- former employment but in a sheltered part- cularly the relationship between anterograde time capacity. and retrograde memory loss in the amnesic Formal neuropsychological testing was syndrome.4 carried out at one, three, 14 and 24 months The University of post operatively (see below). A CT scan per- Cambridge Clinical Case reports formed following surgery showed an area of School, Cambridge Case one low attentuation in the region of the left J R Hodges column A obtained Department of A 45 year old right handed woman, presented fornical (fig la). recently Clinical in July 1985 with a 12 month history of severe MRI brain scan, with contiguous parasagittal Neuropsychology, The paroxysmal bursting headaches, associated Ti weighted images, demonstrated severance Radcliffe Infirmary, of and of the fornices at the level of the IIIrd ven- Oxford latterly with brief episodes paraesthesia K Carpenter weakness affecting the left leg. She had no tricle directly beneath the deficit in the and had con- anterior corpus callosum (fig 2a). Both scans Correspondence to: complaints of memory loss, Dr Hodges, Department of tinued working as a clerk and running her failed to reveal any abnormalities in other Neurology, Addenbrooke's structures the Hospital, Cambridge CB2 house without difficulty. Her family had noted major memory-related (that is, 2QQ, UK no problems with her memory or other higher thalamus, the hippocampus and para- Received 12 February 1990 cognitive function. Physical examination hippocampal regions). Figure 3 illustrates the and in final revised form normal and course of the fornix in 6 March 1991. revealed no abnormalities. Bedside testing of appearance Accepted 8 March 1991 orientation, attention, memory and language a control subject for comparison. 634 Hodges, Carpenter Figure 1 Axial CT scan J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.54.7.633 on 1 July 1991. Downloaded from images in cases 1(la) and 2 (lb) at the level of the foramen of Munro showing an area of low attenuation in the region of the left fornical column (arrow). Case Two high density non-enhancing cyst situated in the A 33 year old right handed man, presented in anterior part of the IIIrd ventricle, approx- May 1987 with a three month history of imately 1 cm in diameter. There was minimal paroxysmal headaches and a single episode of enlargement of the lateral ventricles. loss ofconsciousness. At this time he continued Surgery was performed in May 1987. The to work as a self-employed salesman without cyst was removed by a transcallosal approach to difficulty. His wife had not noticed any impair- the left lateral ventricle, a technique identical to ment in his memory. that used in case 1. A 1 cm incision was made in Physical examination revealed no abnor- the corpus callosum. The pericallosal arteries malities. Bedside testing of attention, orienta- and thalamo-striate vein were identified and tion, memory, visuospatial function and lan- spared. The septum pellucidum was then guage was normal. A CT scan revealed a typical opened and a typical colloid cyst was identified through the foramen of Munro. The cyst was incised and evacuated, the capsule was then Figure 2 Sagittal MRI dissected away from the forniceal columns and images in cases I (2a) completely removed via the left lateral ven- http://jnnp.bmj.com/ through the midline tricle. There were no complications in the showing interruption of the fornices (arrow) at the immediate post-operative period. level of theforamen of As soon as he had recovered from the Munro directly beneath procedure it was apparent that he had the surgical corpus callosum defect. In case 2 developed an amnesic syndrome with clinically (2b) the rightfornical obvious anterograde memory impairment but column was 2pparent on limited loss. temporally retrograde memory on September 23, 2021 by guest. Protected copyright. contiguous parasagittal cuts, but in the other Initially the retrograde amnesia was of approx- patient neither column imately 18 months duration; he was unable to could be demonstrated. recall his operation, presenting complaints or W;:-. ,._' Figure 3 Midline sagittal MRI image in a control subject showing the normal appearance and course of the fornixs .'ig (arrow) for comparison with the two patients. Anterograde amnesia with fornix damagefollowing removal of IIIrd ventricle colloid cyst 635 Table I Results ofgeneral intellectural and memory tests in case 1 foramen of Munro (fig 2b). No other lesions J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp.54.7.633 on 1 July 1991. Downloaded from were Aug 85 Oct 85 Sept 86 Aug 87 Expected shown. (I month) (3 months) (14 months) (24 months) Range* Results IQ Verbal 89 97 Performance 112 120 The formal neuropsychological test results on Full Scale 99 107 cases 1 and 2 are shown in tables 1 and NART' 101 103 2, Digits Forward 5 6 6 6 respectively. The patients' scores were com- Backward 4 5 5 5 pared with established normative data for tests Verbal Memory Paragraph Immed 4 75 3 5 3 5 3 0 8-10 in routine clinical usage. For the more Delayed (60 mins) 0 0 0 0 5-6 experimental tests, normative data were PALT2 Immed 5 0 7 0 7 5 8 0 14-18 Delayed Easy 4 5 6 5 6 derived from 20 neurologically normal controls Hard 0 0 0 0 3-4 subjects, mean 54-2 who Warrington RMT' (SD) age (8 6), Words (raw score) 43 43-46 represent a subgroup of the community-based Faces (raw score) 45 47-48 controls used in a previous Non-Verbal Memory study.6 Form A B A The results confirmed the presence of an Rey Figure Copy 34 29 34 >32 amnesic syndrome which initially affected Recall (45 mins) 6 17 5 19 > 22 Corsi block span 6 6 6 6 anterograde verbal and nonverbal memory to supraspan +2 trials >20 10 6 6-10 an equal degree. In Case 2 there was no Spatial memory test Items recalled 4 5 6-10 significant discrepancy between the estimated Mean displacement 9-1 8-2 5-11 level of pre-morbid IQ, as judged by perfor- mance on the National Adult Test Key: 1 National Adult Reading Test, 2 Paired Associate Learning Test, 3 Warrington Reading Recognition Memory Test, *based on age and IQ. (NART)7 and the post-operative WAIS IQ scores.