Journal of Neuro-Ophthalmology, December 1981, Volume 1, Issue 4

Visual-evoked responses. A new abnormality with focal retinal damage.

A new monocular pattern-shift visual-evoked response abnormality seen with focal retinal damage is described in a patient with a right parietal malignant astrocytoma treated with 3 pulse doses of unilateral intra-arterial carotid BCNU to a cumulative dose of 750/mg/M2. Ophthalmoscopy showed a minimally blurred right optic disc edge with a large flame-shaped hemorrhage in the right superior quadrant at 11 o'clock, one disc diameter from the disc. Visual-evoked response with right eye stimulation demonstrated prolongation of the major P-100 wave in the right occipital area but not the left. Left eye stimulation was normal at both occipital electrodes. Unilateral occipital slowing ipsilateral to pattern shift presentation--with normal evoked responses from the contralateral eye--was seen in a patient with pathology of the retina. Abnormalities of visual-evoked responses must be interpreted in the context of a good ophthalmoscopic examination and not attributed solely to pathology in the optic nerve and more central structures of the nervous system.

J. C1in. N~uro-ophth"'mol. 1: 273-275, 1981. Visual-Evoked Responses A New Abnormality with Focal Retinal Damage HARRY S. GREENBERG. M.D. Abstud A new monocub,r p..Uern_shift visu..l-eyokfd re­sponse ..bnorm..lity SHn wilh foc..1relin..1d..m..ge is dfSCriMd in .. jUlienl with .. righl p.uiet..1m..lign..nl ul«K)'Iom.. tre..lfd with 3 pulse dOSft of unil..ler..1 intu-..rleri.1I ciillrotid BCNU 10 .. cumub,live dose of 750/mglM1 . Ophth.llmoscopy showed .. minimiilllly blurrfd right optic disc edge wilh .I l.uge f).Ime­sh. ped hemorrh.ge in Ihe righl supt'rior qU.ldunt.l1 11 o'dock, one disc di.lmeler from Iht disc. Visu.l­eyokfd rftponse with righl eye stimuliilltion demon­slulfd prolong.tion of tht m.ljor P-loo WiillYf in Ihe right ocdpil.Jol uu but nol Iht left. ldl tye stimul.l­lion wu nonn.ll.lt bolh occipitiilll tlectrodes. Unit..ltnl CK:dpil.JoI slowing ipsil.lIU.lIIO p.1o"tm shift prtsenu.­lion- with norm..1tvoked responses from tht contriill­I. ttnl tye-wiillS SHn in iiIl p.1otitnl with p.llhology of tht rtliniill. Abnonn.llilies of visu..l~vokfd responses Ulust M inltrprttfd in tht conlut of .. good ophlh.ll­moscopic t'Umin.tion ..nd not ..ttribuled soltly 10 p"­Ihology in tht optic nt.rvt .Ind mort erntul slructures of tht ntrvous sys;tem. A monocular p.tttern-shift visual-evoked re­sponse abnormality seen with focal retinal damage is described in a patient with a right parietal malig­nant astrocytoma. Methods Visual-evoked responses were obtained with monopolar electrodes referred to the joined ears. A DeVices limited SP-IOO pattern shift gt'nerator (60 cm from the subject) was triggered by a Ht'w­lett- P.lIck..ard 21168 computer and Grass 5-88 stirn· ul.lltor at 1 Hz. The shift w.s for 300 ms. Two trials wt're obtained. The response W.lS processed and ;ecorded with a 24-channel averaging sySlem, con­sisting of a Grass Model 78 EEG machine, Hewlett· p..ckard Z1168 computer system, and Ht'wlelt· p..ck..ard 10048 x-Y plotter.' The inlernational 10­20 system w,as used for el«trode placemt'nt with the Oz electrode on the right occipital .Irea and the 01 electrode on the left. From Ihf ~p.onmfnl of NfUrology, UniVl'fS'ly of Mi(h,jt<On Mfdiul CfnlfT. Ann Arbor. M.chig.on. December 1981 Case Report A 56-year-old, right-handed female was trans­ferred to the University of Michigan Hospital on 1·31-80 with a I-week history of headaches and progressive obtundation. CT scan demonstrated a contrast-enhancing right parietal mass, confirmed by angiography. Craniotomy with sublotal resec­tion on 2-4-80 revealed a grade III malignant astro­cytoma. The visual acuity on 3-14-80 was 20/30 in both eyes with normal visual fields and ophthal. moscopic examination. A minimal hemiparesis with extinction to double simultaneous stimulation was present on the left side. She r«eived her First of three courses of intra-,arterial carotid BCNU on 3-14-80 and the last on 6-12-80, to a lolal dose of 750 mg/M2 • On 7-21-80. Ihere were no visual complaints, but ophthalmoscopic examination of the right eye showed a hemorrhage one disc di,ameter tempo­rally dt II o·c1ock. Visual acuity was unchanged at 20/30 in both eyes with glasses. Visu,al-evoked responses with right eye stimulation (00) dem­onstrated prolongation of the major P100 wave in the right occipital area (0:1), but not the left (01). The recorded response to left eye stimulation (OS) was normal at at and ().~ (Fig. 1). Three days later she complained of decreased vision in the right eye and was tesled in the de­partment of ophthalmology where her visual acuity was recorded as 20/50 in the right eye and 20/15 in the left eye. The anterior chamber had no ct'lls or flare. Schiotz tensions were IZ mm Hg bilat­erally. Funduscopic eXdmindtion showed diffuse peripapillary and posterior pole hemorrh,ages, cot­Ion wool exudates. and disc edema in the right eye and a normal examinalion in the left eye (Fig. 2). Ove'r the nt'xt 3 ddys her vision decreased 10 light perception in tht' right eye. She rt"Ceived 6CX>O R whole br<lin radidlion therapy between 10-1-80 and J 1-15-80. On 11-19-80 her visu.tl acuity WdS 20/40 in the right eye. At this time thE' only hemorrhagt' in the fundus was superotemporallo the oplic disc (Fig. 3). Discussion 8CNU (1,3-bis-Z-chloreothyl-I-nitrosourea) is a non phase-specific alkylating agent used for intra- 213 0' OD ----~ .. ". .-. 0' .., Ol~--'- ... -...;-.' 0· ... figll" I. V,~u..l-f'YOk~ rP'!oponsn 7/21/80 R1lthl ~ Sl,mull11o" 100, dtm­mon,;. l."hnlt prolon~lion of Ih, r-loo W.W: In 1M nJtht O(c.p'loll .If'" 10,1. WIth AOl'II'I.il t..1f'ftCy to Ihr ItoM occ,p.,..l .rr. rO,I. 1m ~ ~hmul"hon ,OS, norm,,' .., D,.nd 0, ,.. Figure 2... ) rundu~ photogr.?h of th, f,g!'!1 'y' 7/24/~ ""th d.ffu~ r<-"rJr,llJro.· JnJ I"'~lt'rl\'f l"lt h,morrh.grs. (olton woo; rxud",l's, .nd disc C'd,m. (bl Ldt ryt nomul arterial cdfotid chemotherclPY of malignant gliomds and intravenous chemotherilPY of syst£'mic mdlig­ndnd(' s.~·:1 It produces a unilaterdl toxic .t'lio.11 vasculitis ipsitaterallo the sidp of the inlrd-.H1Nidl Cdfotid infusion visible by ophthdlmoscopic Pl(­amination (Fig. 2 and J). F1uoreSCt'in .mgiography in other pdlients with refinell velsculitis secondary to intrel-elrterial BCNU nas snown s~mentell peri­vascular stainin~ elnd nyperfluor('S(ence of tnl' op­tic disc consistent with el tOllic rE'tinal v.\sculitis. The opnthdlmic drtl'ry nelS bE'E'n norm.al witn no ('Videncl' o( a ~l'nl'relllzl'd cl'rl'brell v.lsculitis on rl'pE'elt mtl'mell c.lrotid drtery eln~iOf:rolm.~ V" ,uI I, ..."krd r("Spons("S ml'elsurl' conduction of nerve impulses from tne centrell three degrees of tne visuell field of the retina to tne occipital lobe, with the potentioll helying predominantly a fovedl origin,' The oIllons arising from gelnglion ceUs temporal to the rignt mdculd sweep around the central retinal arE',) to enler the nervehedd on its temporal border. These fibers course to the ipsilateral lateral genic­ulate body dnd syndpse with fibers which trayel to thl' right occipital cortex,~" Nasal macular ganglion cell axons pdSS into the optic nerve like the spokes of d wneel, cross at the optic chiasm and conduct to the opposite occipitallobe.u The nonnal response at (h with left stimulation 'oum.d of Oink,oII Neuro-ophth.almology FiJ'l~ J. Fundus pMtl.'tU.lph of 1M nlhl ~ 11I1Q/NJ dnn. ClIUl:r.ItInJ Mnoorrft.,~ II 10 I o·clocl. wllk Mrv~ f,oo U)"I'T "U.lta indiut~ th..lt n~ith~r th~ nght optic tract nor th~ right occipital lobe- is th~ sit~ of p.llhology and that th~ O! occipital ~1t."'Ctrod~ IS properly in plac~. The normal ~ponse at 0, with nghl ~y~ stimulation indiC<ilt~ noll1Ul conduction from th~ nu.al mAculA to th~ optic n~rv~ through Ih~ OptiC chiasm to the left ocripitallobe-. Patt~m·shift visual-evokrd r~ponSt" conduction d~lay seen only al th~ ipsil,ll~ral.occipital lobe, with nonnal evok~d r~pans~ from the contralat· ~ral ty~ indiutes primarily prechiasmatic involve· ment of t~mporal m<ilcula ganglion cells or their nons, although recent half·field stimulation sug­gests the delay may be seen maximally at the contralateral occipital lobe.4 A hemorrhage in the Otc~mbf'r 1981 Creen~rg rellnoll ".ons of the temporal melcul.J g.Jnglion cells w.Js observed funduscopicell1y th~ d.Jy of Ihe vis· u.l.evokrd r!.'Spanse recording (F,g. I) elnd WelS the only hemorrhdge remaimng " months later when vision rt'lurned (Fig. J). Tht' gredl Importance of fmdin): a Idrgt' hemorrhagt' is thelt retmdl pathology molY produce oIbnonnolli!l~ m th~ visudl-rvoked r..-spanse.•lnd oIbnorm.thti~of the VISUdl-evoked response must be mterprete'd m the cont~l(t of a good ophthdlmoscopic ~XdmlRatlon. R~ferencn KOOt, I<...A., .rod M.rshdll, R L: V,su.' Evokt'd Po­r.. nr,.ls In C..ntr.l DljOrckrs 01 rh.. V,sucll 5ysr..m_ ApptrodUt ...·24. H<lTptr &. Row, Nf'W York, 1979. pp.157-159. 2:. Greenbforg. H.S. Ensmmge', W.O.• 5E'eg~r. I r., et dl.: Intrd'dr1t'ridl BCNU chemothtrdpy for Ihe lredl· mtnt of mdhgJUlnl ghomdS of Ihe ctnlrdl nervous system Cdroc..r T,...,. R..p. lin pTt'Ssl J. Holldnd.J.F, ..nd Frt'. E.. III (Cds ,. Cdnc..rMt'dlcme. u .. &. Feb'ier. Ptlll..dtiphloi. 1973. PI' 620-62:1. 4 Sokol. S. V,su..1 t'VOk~ poItnlloil In Ekctrodj· ...gnosrs lfI CllfIK..1 N~rolotrY, M J. Amlnoff, Ed. ChuTrlllllLJvlnplone. New York, 1979, pp. 348-J69. 5. V,..bK. f.: 1M l~por..1r..pht of 1M hutn.J.ro rrtiJUI. Am 1 Ophrh.lmol. 62: 926-9.3&, 1906. 6. W..lsh. F.8....nd Hoyt. WF..: OlflK..l N..u~ph­Ilwlmology, Vol 1 (Jrd tel, W,lh..ms &. W,lIuns. a...Jtlmo~, 1969, pp. 7-9 Ac.knowlrdgment. The dulhor IS mdebled 10 CSdbol M..r1ony, ..nd Ihe Oep.lrtffitnt of Ophlh..Jmlc Photosrdphy for tdking the fundus photogr..phs. Writ.. (or reprints ro: Hury 5. Gretnbt'rg. M.D.. Dtp.lr1ment of Neurology, University of Michig.lrl Med· luI Ct'nltr, Ann Arbor, Michig.ln 48109.