Journal of Neuro-Ophthalmology, December 2005, Volume 25, Issue 4

The 57th Annual Meeting of the American Academy of Neurology

The 57th Annual Meeting of the American Academy of Neurology, Miami, Florida, April 9- 16, 2005 There were 1,405 scientific papers and poster presenta­tions at the 57th Annual Meeting of the American Academy of Neurology held in Miami Beach, Florida from April 9 to 16, 2005. Abstracts are published in Neurology 2005; 64: Suppl 1. We have summarized the material of most interest to neuro- ophthalmologists. OPTIC NEURITIS AND MULTIPLE SCLEROSIS Brain MRI is an established biomarker of disease in multiple sclerosis ( MS), and data on the impact of MS and acute optic neuritis on retinal nerve fiber layer ( RNFL) thickness, as measured by optical coherence tomography ( OCT), are beginning to emerge. A recent investigation examined the relation of visual function to RNFL thickness and brain MRI parameters in an MS cohort. Scores for low-contrast letter acuity ( Sloan charts) and contrast sensitivity ( Pelli- Robson), the leading candidates for visual compo­nents for inclusion in the MS functional composite, were significant predictors of average overall RNFL thickness ( P < 0.001) and of lesion burden on T2- weighted MRIs ( P = 0.001 for Sloan charts; P = 0.03 for Pelli- Robson) accounting for age. The greatest reductions in RNFL thick­ness were noted among eyes of MS patients with a history of acute optic neuritis. However, MS eyes without an optic neuritis history also demonstrated abnormalities. These results not only confirm a role for axonal loss in the anterior visual pathways of MS patients but demonstrate correlations of low- contrast letter acuity and contrast sensitivity with structural biomarkers, supporting their validity as clinical trial outcome measures ( Wu GF, Philadelphia, PA, POL025). Visual dysfunction is a common manifestation of MS and may therefore have important effects on health- related quality of life ( FfRQOL). The 25- Item National Eye Institute Visual Function Questionnaire ( VFQ- 25) has been used in a variety of ocular conditions and ophthalmic clinical trials. A study was performed to examine whether a 10- Item Neuro- Ophthalmic Supplement could increase the capacity of the VFQ- 25 to capture self- reported visual dysfunction in patients with neuro- ophthalmic disorders, particularly those asso­ciated with diplopia or optic neuropathy. Patients included those with optic neuritis, MS, idiopathic intracranial hyper­tension, ischemic optic neuropathy, ocular myasthenia gravis, thyroid eye disease, and ocular motor palsies. Scores for the VFQ- 25 + 10- Item Neuro- Ophthalmic Supplement ( com­bined scores) had a greater capacity to distinguish neuro-ophthalmically impaired patients from disease- free controls ( receiver operating characteristic [ ROC] curve area, 0.77) than did the VFQ- 25 alone ( ROC curve area, 0.73; P = 0.001). VFQ- 25 + Supplement scores correlated signifi­cantly with binocular and with worse eye visual acuities ( rs = 0.38 - 0.41; P < 0.0001), and Neuro- Ophthalmic Sup­plement items demonstrated appropriate levels of reli­ability. The 10- Item Supplement is a valid measure of self- reported visual dysfunction in neuro- ophthalmically impaired patients. This new scale captures symptoms and limitations related to diplopia and will be used to complement the VFQ- 25 in clinical trials and other research ( Balcer LJ, Philadelphia, PA, P01.031). Sixty MS patients were studied to establish the relationship of infections to MS exacerbations. MS attacks occurring between two weeks before and five weeks after an infection were considered temporally related to infection. A total of 127 infections were recorded in 53 patients, and 124 exacerbations occurred in 49 of the 53 patients. There was an increased risk of relapses temporally related to infec­tion ( odds ratio, 3.2; P < 0.0001). Exacerbations that were temporally related to infection were more frequently asso­ciated with severe and sustained deficits than those that were not temporally related to infection. The number of Gd- enhancing lesions was higher during exacerbations temporally related to infection than in those that were not temporally related to infection. This study demonstrates a significant association between systemic infection, risk of MS clinical relapse, and degree of MRI activity ( Correale JD, Buenos Aires, Argentina, P03117). NEUROMYELITIS OPTICA Neuromyelitis optica ( NMO) is a severe inflamma­tory central nervous system ( CNS) disorder with a predi­lection for the optic nerves and spinal cord. Because of the potential overlap with MS with regard to clinical and neu-roimaging findings, the diagnostic criteria for NMO have been recently re- examined and revised. These new criteria have modified those published in 1999 ( Wingerchuk et al., Neurology 1999; 53: 1107- 14) to update MRI findings and to incorporate a novel serum autoantibody marker, NMO- immunoglobulin ( Ig) G. Investigations for these studies calculated sensitivities and specificities for each component of the 1999 NMO diagnostic criteria using a new 118- patient cohort. Combinations of individual criteria, including NMO- IgG, were tested to optimize the potential for correct diagnosis. Among patients with NMO ( n - 84) versus MS ( n = 34), criteria that had the greatest capacity to distinguish NMO from MS were the presence of NMO- IgG ( sensitivity, 75.3%; specificity, 93.3%) and spinal cord T2- lesion length extending beyond three vertebral segments ( sensitivity, 97.0%; specificity, 79.0%). Neurological symp­toms indicating disease outside the optic nerves and spinal cord were seen in 17 NMO patients ( 20.2%). Based on these findings, the authors suggested criteria for diagnosis of NMO. Absolute criteria: presence of optic neuritis and acute myelitis ( but disease in other areas of CNS allowed); supportive criteria: 1) spinal cord MRI with lesion( s) ex­tending over three or more vertebral segments or 2) NMO-IgG seropositivity ( Wingerchuk DM, Scottsdale, AZ, P01.033). As emphasized by studies refining the diagnostic criteria for NMO ( P01.033 above), an NMO diagnosis is no longer precluded by the presence of clinical or imaging abnormalities outside the optic nerves or spinal cord as long as the patient meets the new NMO criteria described the previous paragraph. Importantly, the former ( 1999) criteria required a normal brain MRI. The brain MRI findings for 60 patients who met revised criteria for NMO ( P01.033 above) were described in a recent study. In 26 ( 43%) of 60 patients, brain MRI was normal at a median of 1.6 years ( range, 0- 29 years) after the onset of symptoms. Seventeen patients ( 28%) had non- specific abnormalities that were generally located in the deep white matter and few in number ( only four [ 6.5%] patients had more than four high T2 signal foci). Typical MS- like lesions were found in only six patients ( 10%), five of whom were seropositive for NMO-IgG. The remaining 11 patients ( 19%) had MRI findings considered atypical for MS; brainstem lesions were seen mostly among children. Because brain MRI abnormalities were noted among - 50% of patients who otherwise had classic findings for NMO, diagnostic criteria have been revised to allow for brain involvement ( Pittock SJ, Scottsdale, AZ, P01.036). Because brain MRI techniques have continued to evolve, atypical findings have been noted more frequently in the brains of NMO patients. Given the contiguity of the hypothalamic regions to the anterior visual pathways, hypothalamic involvement in patients with NMO is perhaps not unexpected. Two patients with otherwise classic fea­tures of NMO were described as having hypersomnolence, hyponatremia, and hypothermia. MRI scans revealed new areas of hyperintense signal in the hypothalamus in the absence of other brain parenchymal lesions. Additional sim­ilar cases were identified from the literature, and this series again supports revision of the NMO diagnostic criteria to include involvement beyond the optic nerves and spinal cord ( Poppe AY, Montreal, QC, Canada, P01.037). GENETIC OPTIC NEUROPATHIES Patients with Friedreich ataxia ( FA) develop optic neu­ropathies, most frequently after development of gait and limb dysfunction. Sixteen molecularly defined Italian FA patients with quantified GAA were assessed with visual acuity, fundus photos, 30- degree Humphrey visual field, Ishihara color plates, OCT, visual evoked potentials ( VEP), and electroretinography ( ERG). All patients showed optic nerve damage as assessed by OCT and visual fields. Fiber loss was typically peripheral; decreased visual acuity was present only when central fibers were lost. VEP was altered in eight ( 56%) of the patients. In six, they were significantly delayed with reduced amplitudes; in three, the responses were absent. ERGs were normal in all patients. The degree of fiber loss, expressed as thickness of the nerve fiber layer as measured by OCT, was significantly correlated with the GAA expansion in the smaller allele of the frataxin gene ( P = 0.002; r = - 0.69 for the peripheral sectors). OCT was the most sensitive test in showing optic neuropathy ( Forruna F, Milan, Italy, SOL003). Investigators designed a battery of clinical measures that may be used for outcomes assessment in FA therapeutic trials. FA candidate performance measures, including the timed 25- foot walk, 9- hole peg test, low- contrast letter acuity, and RATA test ( a test of speech) were evaluated in a cohort of 131 FA patients at six academic medical centers. Scores for individual components ( including vision) and for the combination of performance measures correlated signifi­cantly with neurologic disability, activities of daily living, and disease duration ( rs = 0.40 - 0.89; P < 0.0001). Visual function scores were also found to be lower in the FA cohort compared with disease- free controls, further supporting the inclusion of low- contrast letter acuity in an FA outcomes assessment battery. Given the high proportion of FA patients who progress to a non- ambulatory status in adulthood, inclu­sion of measures that capture vision, arm function, and speech will ensure sensitivity and applicability throughout the course of disease ( Lynch DR, Philadelphia, PA, P01.104). To further development of an animal model for Leber Hereditary Optic Neuropathy ( LHON), mice received intra­ocular injections of an adeno- associated virus- ribozyme directed against the murine mitochondrial ND4 subunit of complex I. Their ganglion cells showed hyperchromatic cyto­plasm and nuclear condensation suggestive of apoptosis. Optic nerves showed secondary demyelination with axonal loss. Transmission electron microscopy revealed swelling and vacuolization of mitochondria with dissolution of cristae. Allotopic expression of a mutant R340H ND4 results in histopathology similar to that of patients with LHON harboring the Gl 1778A mutation in mitochondrial DNA ( mtDNA). This is a step further in development of an animal model of LHON ( Qi X, Gainesville, FL, SO 1.001). In addition to the three most common mtDNA mutations that occur in patients with LHON, novel path­ogenetic mutations continue to be discovered. Overlap with other mitochondrial disease phenotypes, such as mitochon­drial encephalopathy, lactic acidosis, and stroke- like epi­sodes ( MELAS), has also been described for mutations involving the ND5 subunit of complex I. An Italian family with a maternally inherited LHON phenotype demonstrated an ND5 mtDNA mutation ( G13042A/ ND5) that was path­ogenetic for LHON yet had been previously described in a case of MELAS. This report underscores the potentially variable clinical expression that may occur in the setting of mtDNA mutations and reinforces the need for consider­ation of a variety of mutations in patients with optic neu­ropathies consistent with LHON ( Valentino ML, Bologna, Italy, P01.029). An attempt to use neuroprotection to prevent second eye involvement with LHON was reported. In an open- label prospective pilot study, nine patients with one- eye vision loss for less than six months and normal visual function in the other eye were treated with brimonidine purite 0.15% ( Alphagan P) four times daily in the unaffected eye for up to two years. Visual acuity was the primary outcome mea­sure. Secondary measures included changes on automated perimetry and quantification of the relative afferent pupil­lary defect. There were eight men and one woman enrolled, aged 13- 54 years ( mean, 32 years); eight had the 11,778 mtDNA mutations, and one the 3,460 mutations. Despite normal visual acuity and visual field mean deviations at baseline, seven patients had minimal changes in the central visual field of the study eye. All patients had deterioration of their second eye vision. Topical brimonidine purite in this dosage was unsuccessful in preventing second- eye involvement ( Newman NJ, Atlanta, GA, SOL002). Horizontal gaze palsy with progressive scoliosis ( HGPPS) is a rare syndrome with congenital absence of conjugate horizontal eye movements from birth and a severe progressive scoliosis. It is caused by mutations in the human axon guidance gene ROB03 that is important in midline crossing during neurodevelopment. Two genetically denned HGPPS patients were studied. One patient underwent struc­tural MRI, and one underwent Brain Stem Auditory Evoked Responses ( BAERs). A Tl- weighted three- dimensional volume MRI provided anatomical information and was co- registered to the diffusion tensor imaging ( DTI) data. Diffusion tensors were calculated from diffusion- weighted images using standard methods. The structural MRI showed reductions in the size of the pons, medulla, and cerebellar peduncles and flattening of the rostral medulla. Color- coded DTI showed absence of the decussation of the superior cerebellar peduncles and absence of the major crossing fibers representing the trapezoid body at the pontine level, confirmed by the BAER results in the second patient. Supratentorial crossing fibers appeared normal. Muta­tions in ROB03 resulted in DTI- defmed abnormal midline crossing of several white matter tracts in the hindbrain. This is the first report of the lack of decussation of both the superior cerebellar peduncles and the auditory/ vestibular pathways ( Sicotte NL, Los Angeles, CA, SO 1.005). Two children with severe microphthalmia and one with anophthalmia developed progressive severe white matter degeneration. The patients were unrelated, but parents originated from the same Pakistani village. Workup for known causes of white matter degeneration was nega­tive. The authors propose that this is a novel example of a leukoencephalopathy in which the abnormal cerebral white matter disappears over time ( vanishing white matter) ( Kanavin OJ, Amsterdam, Netherlands, S65.001). IDIOPATHIC INTRACRANIAL HYPERTENSION Obesity and weight gain are known risk factors for idiopathic intracranial hypertension ( IIH). However, the profiles of body mass index ( BMI; = weight [ kg]/ height2 [ meters]) and weight change that are most associated with IIH have not been denned. A recent case- control study designed to pilot a new risk factor questionnaire and to examine patterns of weight gain and obesity has provided new insight. This study included 34 newly diagnosed IIH patients and 41 age- matched controls. As expected, higher levels of BMI were associated with progressively greater risk of IIH in this cohort ( BMI, 25- 30; odds ratio in favor of IIH = 6.5; BMI 30- 35: odds ratio = 19.5; BMI > 35; odds ratio = 26.0; P < 0.01, \ 2 f° r trend). Higher percentages of weight gain during the year before diagnosis ( or corresponding reference time for controls) were also associated with IIH ( 5%- 10% weight gain: odds ratio = 3.5; 10%- 15%: odds ratio = 10.2; > 15%: odds ratio = 15.2; P < 0.01). Most interesting was the finding that among patients with moderate weight gain ( 5%- 15%), those with BMIs < 30 ( ideal or slightly overweight) were at greatest risk for IIH. Results of this study support clinical obser­vations that associate IIH with increasing degrees of weight gain and indicate that weight gain- associated IIH may develop even among patients of ideal or slightly overweight BMI profile ( Daniels AB, Philadelphia, PA, P01.032). VESTIBULO- CEREBELLAR PATHWAY DYSFUNCTION Whereas skew deviation is typically attributed to brain stem lesions that disrupt otolithic vestibular projections to the third and fourth nerve nuclei, it may also occur in the setting of isolated focal cerebellar lesions. Focal cerebellar lesions were identified in five patients with vertical ocular misalignment who had no evidence of brainstem in­volvement ( or neuromuscular disease). After detailed testing of the vestibulo- ocular reflex, patterns were found that implicate imbalance of the utriculo- ocular reflex as the mechanism for skew deviation ( Wong MF, Toronto, ON, Canada, POLO 13). Benign paroxysmal positional vertigo ( BPPV) is a common cause of vertigo encountered by neurologists and neuro- ophthalmologists. The assessment and treatment of BPPV has been systematically investigated by several research groups. BPPV is unique among other causes of vertigo in that it results from misplaced otoconia in the semicircular canals. Treatment, therefore, centers on repo­sitioning of the otoconial debris within the canals. Among 524 consecutive patients who presented to an emergency department in Italy with symptoms of dizziness, 243 were found to have BPPV that localized by Dix- Hallpike maneu­ver to the posterior or anterior canals ( n - 202), the hor­izontal canal ( n = 35), or the posterior and horizontal canals combined ( n - 6). Canalith repositioning treatment ( modified in cases of horizontal canal BPPV) produced resolution of vertigo symptoms in all but six patients ( Del Colle R, Legnago, Italy, P01.019). The efficacy of a new treatment maneuver for posterior canal BPPV was also investigated. This new treatment, the Gans Repositioning Maneuver ( GRM), is a hybrid of the Semont Liberatory Maneuver ( SLM) and the Canalith Repositioning Maneuver ( CRM). Although these estab­lished maneuvers are well tolerated and easily performed on most patients, those with hip problems that may be ag­gravated by brisk lateral motion during the SLM, and individuals with a contraindication to neck hyperextension ( as required in the CRM), need a modified version of these treatments. The GRM consists of the following: 1) the patient is placed in a side- lying position ( used in SLM); 2) the patient rolls onto the shoulder opposite the involved ear ( with head turned away from involved ear throughout rotation); and 3) the patient is seated upright. Patients with posterior canal BPPV treated with GRM in a recent series ( n = 207) experienced resolution in 80.5% of cases after a single treatment; 95.5% resolved with two treatments. Symptom recurrence rates were only 5% within a three-month period, and results were in agreement with previous data for the SLM and CRM. The GRM was thus shown to be effective in posterior canal BPPV and may provide broader access to repositioning maneuvers for groups of patients with hip and neck problems that preclude traditional treatments ( Roberts RA, Semiole, FL, P01.016). One of the most important challenges facing physicians in an emergency room is differentiating peripheral vestibular dysfunction from more serious brain stem causes ( cerebellar or medullary infarction) of sudden- onset vertigo and ataxia. An abnormal head impulse sign ( HIS) on vestibular testing is thought to provide clinical evidence in favor of a peripheral vestibular etiology. To perform the HIS, the patient fixates a target while the examiner moves the patient's head rapidly to each side. The occurrence of a refixation saccade during this maneuver is a sign of decreased neural input from the ear ipsilateral to the head turn. ( If there is decreased neural input, the eye travels with the head during the high- velocity movement, and a refix­ation saccade is required to re- foveate the target.) Among 38 study participants ( mean age, 64.3 ± 13.1 years), 5 were diagnosed with peripheral vestibulopathy, and 27 were di­agnosed with cerebellar infarcts in various vascular territories ( 19 posterior inferior cerebellar arteries [ PICA], 3 superior cerebellar arteries [ SCA], and 5 anterior inferior cerebellar arteries [ AICA]). Five patients had a lateral medullary syndrome ( LMS), one had a pontomedullary infarct, and ten patients had strokes in multiple vascular territories. The HIS was normal in 18 of 19 PICA infarcts, 3 of 3 SCA infarcts, and in all LMS patients who presented initially with isolated vestibular signs. In the three patients with AICA infarcts and abnormal HIS, the abnormal HIS was attributed to involvement of vestibular nuclei or peripheral vestibular nerve ischemia. The authors concluded that a normal HIS tends to exclude pure brain stem/ cerebellar stroke in patients with non- specific acute onset symptoms of vertigo and ataxia ( Kattah JC, Peoria, IL, POLO 18). The National Health and Nutrition Examination Survey ( NHANES) provides cohort data on a large nationally representative sample of the U. S. population. The prevalence of self- reported dizziness among 3,002 men and women aged 40 years old who participated in NHANES from 1999 to 2000 was reported along with the demographic characteristics, relationship to cardiovascular risk factors, and response to treatment for dizziness in this cross-sectional sample. Dizziness within the past year was re­ported by 771 ( 26%) of the 3,002 persons screened. The symptoms lasted less than two weeks in 71%, two weeks to three months in 9%, and more than three months in 20% of the persons with dizziness. The prevalence according to age groups was 20% for age 40- 59 years, 27% for age 60- 79 years, and 40% for age 80 years and older. Compared with persons who did not report dizziness, persons with dizziness were more likely to be women ( 61% versus 48%, P < 0.05) and to have a higher mean systolic blood pressure ( 137/ 24 versus 133/ 21 mm Hg; P < 0.05). Treatment was instituted in 265 ( 35%) of the 771 persons with dizziness. It consisted of medication ( n = 149), ear surgery ( n = 8), other surgery ( n = 9), vestibular exercises ( n = 33), or other treatments ( n - 66). Improvement after treatment was reported among 189 ( 71%) of the 265 treated patients. The survey demonstrates that dizziness is a very common neurological symptom that affects over 20 million adults aged 40 years and older in the United States. Approximately 4 million adults will have symptoms that last over three months. A larger sample is required to appropriately diagnose and treat dizziness among adults ( Mohammad YM, Columbus, OH, P03.43). MYASTHENIA GRAVIS Patients with ocular myasthenia gravis ( OMG) expe­rience diplopia and ptosis that may be disabling. Mycophe-nolate mofetil ( MMF) was administered to 31 consecutive patients with OMG at escalating doses to a target of 1.0 g/ d. Patients had been on prednisone and were started on MMF because of adverse effects, objection to corticosteroid treat­ment, or disease progression. Prednisone ( 40- 60 mg/ day) was given during MMF dose escalation, and all were tapered off prednisone after stabilization of symptoms. One patient with thymoma underwent thymectomy. During an average follow- up period of 30 months, 84% of patients remained on MMF therapy. Adverse effects, including nausea, vomiting, and diarrhea were noted, but serious infections and cytopenia were not seen, and therapy was generally well tolerated. None of the patients who continued on MMF ( 26 of 31) developed bulbar or limb weakness within 2 years of onset. Relapses ( ptosis and diplopia) occurred in 12 of 31 patients, and they were treated with pyrido­stigmine. Larger randomized trials are planned to further examine the potential for MMF to treat OMG and to delay or prevent onset of generalized symptoms ( Chan JW, Las Vegas, NV P01.030). A case of primary CNS lymphoma was reported after 37 months of treatment with mycophenolate mofetil for myasthenia. This is reported as the first such patient in a non- transplant population ( Vernino S, Rochester, MN, P01.070). Cogan's lid twitch is often touted as a relatively specific clinical sign of OMG, reflecting fatigability of the levator palpebrae muscle. In a series of 35 patients with symptomatic ptosis, sensitivity of Cogan's lid twitch sign was found to be 50%, consistent with Cogan's original findings. Whereas specificity was 91%, the positive pre­dictive value was 25% ( present in one of four patients diagnosed with MG), emphasizing that other etiologies for ptosis may be associated with Cogan's lid twitch sign ( Bhatt A, Detroit, MI, P01.026). Repetitive nerve stimulation ( RNS) was performed on the radial nerve recording from the extensor indicis proprius in ten normal controls and ten patients with MG who had a clinical history and examination consistent with the diagnosis of MG and positive acetylcholine receptor antibodies. A larger decrement was found after radial than ulnar stimulation ( 17.4 % versus 7.4%). Forty percent of subjects demonstrated > 10% decrement on radial RNS without significant decrement on ulnar RNS ( Rubin D, Jacksonville, FL P03.044). VISUAL FIELDS Homonymous hemianopia ( HH) is a disabling visual manifestation of hemispheric infarct, hemorrhage, tumor, or head trauma. Any recovery of HH defects is thought to occur within six months of onset, but the natural course of such recovery has not been examined in detail. A series of 111 cases ( complete HH in 38% and incomplete HH in 62%; infarctive in 55%, hemorrhagic in 18%, tumorous in 15%, traumatic in 5%, and neurosurgically- induced in 3%) demonstrated improvement or resolution in 63 ( 55%) cases. The probability of improvement did not correlate with age, type of lesion, or extent of defect, although resolution was seen more often with incomplete defects. Importantly, im­provement of visual field was noted to occur after six months in eight patients, providing evidence for spontane­ous recovery that may be useful when evaluating the ratio­nale and effectiveness of rehabilitative therapies. Whether such prolonged recovery represents true improvement of visual field function or merely increasing capacity to per­form visual field testing remains to be investigated ( Zhang X, Atlanta, GA, P01.027). A study looking at the correlation of neuroimaging with congruity of HH was presented. Among 904 patients, 548 ( 70%) had incomplete HH. Of these, 373 ( 68%) were congruous, and 175 ( 32%) were incongruous. There were no significant differences between the two groups with respect to age, sex, and side of the visual field defect. Fifty-five ( 84%) of 64 bilateral HH and 318 ( 66%) of 484 unilateral HH were congruous ( P = 0.001). Congruity was more common in macular- sparing HH ( 88%), paracentral HH ( 82%), and quadrantanopic HH ( 69%) than in other incomplete HH ( 35%) ( P = 0.001). HH after stroke was more often congruent ( 72%) than after trauma ( 55%), tumors ( 55%), or demyelination ( 53%) ( P = 0.001). Occipital lobe lesions resulted in the most frequent congruity ( 84.8%). Isolated occipital lesions produced congruous HH in 83%; however, congruity was also seen in 55% of temporal lobe lesions, 40% of parietal lobe lesions, 62% of basal ganglia lesions, 50% of optic tract lesions, and 57% of lateral geniculate lesions. Of the 118 congruous HH cases with follow- up, 7% resolved, 30% improved, 58% remained stable, and 4% worsened. Of the 52 incongruous HH cases with follow- up, 6% resolved 33% improved, 42% remained stable, and 20% worsened. Perhaps the most useful in­formation from this study is that at least 55% of incomplete HH secondary to lesions of the optic tract and optic radiations will be congruous ( Kedar S, Atlanta, GA, SI. 006). RETINA Four patients treated with whole- brain irradiation for primary CNS lymphoma developed retinopathy. The clinical presentation of retinopathy included blurred vision ( 2 cases), visual loss ( 3 cases), and floaters ( 1 case). One patient was clinically asymptomatic at diagnosis of reti­nopathy. The median latency from completion of radiation therapy to diagnosis of retinopathy was 25 months. Oph­thalmic signs in these patients included retinal hemorrhages ( 2 cases) and vasculopathy ( 3 cases). No patient had previous diabetes or other vascular disease ( Grimm SA, New York, NY, P01.071). VISUAL PROCESSING Change blindness ( CB) refers to an inability to detect changes in visual scenes because of a failure to encode in­formation into visual short- term memory ( VSTM). A study of CB in a traffic scene in 12 early Alzheimer disease ( AD) patients, 13 older control subjects, and 25 younger control subjects was performed. Half of the trials contained a discrete object that gradually faded in and out of the scene and half contained no change. Participants had to determine whether a change occurred. Advanced age and AD reduced the ability to detect and respond to changes in traffic- related scenes, indicative of increased CB. The authors attributed the increased CB in advanced age and AD to declining control over the focus of attention upon items entering VSTM or decreased VSTM capacity. The AD participants in this study were also more likely than control subjects to report a change when none had occurred, compatible with impaired perceptual decision- making. Cog­nitive decline caused by aging and AD produces increases in CB, which may have consequences for processing key information in a variety of real- world tasks, including au­tomobile driving ( McEvoy S, Iowa City, IA, S61.003). To test the hypothesis that visual and cognitive func­tions deteriorate along with motor function in Parkinson disease ( PD), 61 PD patients were tested on many cog­nitive, basic, and higher order visual functions. PD patients with mild- moderate disease severity were impaired in basic and higher visual abilities, as well as cognitive functions including attention, memory, and executive functions com­pared with elderly controls. The higher order visual and cognitive dysfunction correlated with motor severity, in particular with axial/ gait impairment, and may contribute to some of the dysfunction in PD patients ( Ergun Y, Iowa City, IA, P03.155). A study compared visual hallucinations in patients clinically diagnosed with AD and patients with Dementia with Lewy bodies ( DLB). Hallucinations occurred in 63% of DLB patients and in 8% of AD patients. They occurred earlier in the course of DLB ( 1.7 years) than in AD ( 6 years) ( Ferman T, Jacksonville, FL, S25.001). HEADACHE A case report of episodic posterior hemispheric dys­function with severe headache beginning 17 years after re­section and radiation for a cerebellar astrocytoma was reported. Episodes lasted days to weeks. As part of the syndrome, homonymous hemianopia developed on one side or the other. Electroencephalogram ( EEG) showed unilateral occipitoparietal slowing, and MRI revealed uni­lateral diffuse cortical enhancement on the side correspond­ing to the hemianopia. With resolution of clinical deficits, the EEG and MRI changes resolved. This is the third such reported case after radiation. The authors suggest the acronym SMART for Stroke- like Migraine Attacks after Radiation Therapy ( Lachance D, Rochester, MN, P04.048). STROKE Patent foramen ovale ( PFO) has been implicated as a cause of stroke. Therapeutic options include antiplatelet medications, warfarin, and surgical or percutaneous closure, but there is little rigorously acquired information to support any particular therapy. A survey of cardiologists and neu­rologists who were about to participate in a clinical trial on PFO treatment showed the following results: Neurologists recommended antiplatelet medications for 49% (± SD, 33%) of patients, whereas cardiologists recommended them in 26% (± SD, 26%; P = 0.0003). Neurologists prescribed warfarin for 28% (± 26%), whereas cardiologists prescribed it in 17% (± 22%; P = 0.04). Neurologists chose surgical closure for 23% (± 9%), whereas cardiologists only chose it for 0.2% (± 0.8%; P = 0.05). Neurologists recommended percutaneous closure for 20% (± 21%) of patients, while cardiologists recommended it for 54.5% (± 33.5%, p < 0.0001). Further, 2% of neu­rologists and 9% of cardiologists recommended closing asymptomatic PFOs ( P = 0.2); 6% of neurologists and 24% of cardiologists recommended closure of PFO for SCUBA diving ( P = 0.02). Finally, no neurologists and 14% of cardiologists recommended PFO closure for migraine treatment ( P - 0.01). Clearly, there are differences in the practice patterns of neurologists and cardiologists, with the latter more likely to recommend percutaneous closure ( Messe SR, Philadelphia, PA, P03.065). A study of the sensitivity of magnetic resonance angiography ( MRA) for posterior communicating artery ( PCA) aneurysm was presented. A neuroradiologist masked to the side of the third cranial nerve palsy or suspected aneurysm examined the maximum intensity projection ( MTP) images and source images to determine if the PCA vessel itself or a PCA aneurysm was present. Of 201 PCAs, MIP images showed 106. Source images ( P = 0.0001) showed 182 PCAs. Source images revealed 42 of 43 aneurysms ( missed aneurysm diameter: 2 mm), and MIPs showed 39 ( missed aneurysm diameters: 2- 6 mm). MRA and catheter angiography aneurysm size measurements were closely correlated ( r = 0.97). When source image analysis of MRA is used, PCA aneurysms with a diameter of > 2 mm should not be missed, and the authors suggest that catheter angiography may not be required. Although this may be true, the reliability of the readings clearly relies on the expertise of the person reading the films ( Kupersmith MJ, New York, NY, SOL004). Sleep apnea syndrome ( SAS) has been associated with stroke. Recent reports anecdotally link SAS with nonarteritic anterior ischemic optic neuropathy ( NAION). One possible explanation is a decrease in blood flow In a study of 76 consecutive awake SAS patients and 70 control subjects, mean blood flow velocity ( MV) and pulsatility index ( PI) in the middle cerebral artery ( MCA) and basilar artery ( BA) were measured by cervical and transcranial Doppler ( TCD) ultrasonography. Patients with cervical or intracranial arterial stenosis were excluded. Values of MV in MCA and BAwere significantly lower, and PI values were significantly higher in the MCA in SAS patients. This study demonstrates differences in cerebral hemodynamics between SAS patients and healthy subjects, a finding that may explain the relatively higher stroke risk in SAS patients ( Segura T, Albacete, Spain, S04.006). OCULAR MOTILITY Patients with Fisher syndrome have often had neurologic deficits attributable to brain stem damage, leading to confusion with the diagnosis of brainstem encephalitis. A 62- year- old man with ophthalmoplegia and dilated unreactive pupils after pharyngitis demonstrated increased jitter and blocking on single- fiber electromyography ( EMG), implying that there is a neuromuscular junction disturbance in Fisher syndrome. Muscle strength was normal. Deep tendon reflexes were reduced. Gait was tentative but normal; tandem walking was difficult. Brain MRI was normal. Spinal fluid protein was normal, and GQlb an­tibodies in low titer developed later. Standard EMG and nerve conduction studies were normal ( Lange DJ, New York, NY, P03.048). Oculopharyngeal muscular dystrophy ( OPMD) is an inherited myopathy clinically characterized by onset in adulthood of ptosis and dysphagia, often accompanied by extraocular and limb muscle weakness. In nine patients with OPMD, the EMG findings were reviewed to determine whether neuropathy may be part of this disorder. The average age at the onset of symptoms was 51 years, and average age at the time of the EMG was 62 years. Clinical findings included ptosis in nine ( 100%), dysphagia in nine ( 100%), limb weakness in nine ( 100%), ophthalmoparesis in six ( 66.7%), and distal paresthesias in one ( 11.1%). All patients had characteristic findings of myopathy; none had findings of neuropathy or neuromuscular junction abnor­malities. These findings should be helpful in differential diagnosis because other diseases, including myasthenia gravis, may present with similar symptoms ( Jones LK, Rochester, MN, P03.056). The distinction between epileptic and non- epileptic seizures ( NES) can be difficult and may occur in a same patient. The incidence of NES is 5%- 20% in an outpatient epilepsy population and up to 40 % for inpatients studied at epilepsy centers. Previous studies found that there are some stereotypical movements associated with NES, such as pelvic thrusting and back arching. A study examined eye closure in relation to NES. Among 52 patients with NES, 50 ( 96%) had their eyes closed during seizures. In contrast, only 4 ( 3%) of 156 patients with epileptic seizures had their eyes closed during a seizure. Interestingly, many patients with epileptic seizures would have their eyes open even when their seizures occurred during sleep. The authors conclude that ictal eye closure is a highly reliable indicator for NES ( sensitivity, 96.15%; specificity, 97.44%). Because it is a simple observation that can be easily reported, ictal eye closure could be a very useful screening question in an outpatient setting ( Chung SS, Phoenix, AZ, S30.004). The eye movement abnormalities in 17 patients believed to have a purely psychogenic disturbance were reported. In this group, 15 had convergence spasm, 1 had opsoclonus, and 1 had blepharospasm. Interestingly, only 7 ( 41%) of these 17 patients had visual symptoms ( diplopia or blindness) as their chief complaint. Non- ocular psy­chogenic movement disorders were present in 15 ( 88%). The co- existence of multiple psychogenic signs may be helpful in separating psychogenic from organic eye-movement disorders ( Mejia NI, Houston, TX, POL 168). Mark L. Moster, MD Albert Einstein Medical Center Wills Eye Hospital Thomas Jefferson University Philadelphia, Pennsylvania Laura J. Baker, MD University of Pennsylvania Philadelphia, Pennsylvania