Ronald Tusa - Academia.edu (original) (raw)

Papers by Ronald Tusa

Annals of Emergency Medicine, 2019

Journal of Neurophysiology, 1992

1. Eye movements were measured in three rhesus monkeys after monocular intravitreal injections of... more 1. Eye movements were measured in three rhesus monkeys after monocular intravitreal injections of picrotoxin, a gamma-aminobutyric acid (GABA) antagonist. The effects of this drug were tested when the animals were in a completely dark room, when they performed a smooth pursuit task, and when they viewed either a stationary pattern or a full-field optokinetic pattern rotating horizontally. 2. Between 15 and 20 min after the injection, a sustained conjugate spontaneous nystagmus developed in the dark, with the slow-phase movement in the temporal-to-nasal direction with respect to the injected eye. Peak slow-phase velocity ranged from 15 to 45 degrees/s. The nystagmus persisted for at least 1 h but stopped by the next day. 3. In a well-lit room, the nystagmus was completely suppressed, even during monocular viewing with the injected eye. When the lights were turned off, the slow-phase velocity of the spontaneous nystagmus slowly increased to a steady-state level within 70-120 s. 4. Hor...

Anales De Otorrinolaringologia Mexicana, 1996

Investigative ophthalmology & visual science, 1999

To investigate the incidence and waveform characteristics of periodic alternating nystagmus, (PAN... more To investigate the incidence and waveform characteristics of periodic alternating nystagmus, (PAN) in congenital nystagmus (CN). In a prospective study, 18 patients with CN without associated sensory defects agreed to undergo eye movement documentation using binocular infrared oculography. Two of the 18 had a diagnosis of suspected PAN before entering the study. The patients sat in a dimly lit room and viewed an LED (4 min in diameter) located in the primary position, at a distance of 100 cm. During an 8-minute recording, patients were read a story of neutral interest to hold attention at a constant level. PAN was defined as a left-beating nystagmus, a transition phase, a right-beating nystagmus, and a final transition phase; the sequence was then repeated. Seven of the 18 patients had PAN (median cycle: 223 seconds, range 180-307 seconds). The periodicity of the cycles for each adult patient was regular, although the phases within a cycle were often asymmetric. Six of the seven pat...

Yearbook of Neurology and Neurosurgery, 2009

To assess the demographics, clinical presentations, auditory and vestibular findings, value of se... more To assess the demographics, clinical presentations, auditory and vestibular findings, value of serologic tests, and treatment outcome in autoimmune inner ear disease (AIED). Retrospective chart review. Tertiary care centre. Sixty patients with confirmed AIED, with and without systemic disease. Diagnostic auditory, vestibular, and serologic tests and treatment with steroids. Auditory, vestibular, and serologic findings and treatment outcomes. The female to male ratio was 2:1. Forty-nine patients presented with unilateral or bilateral hearing loss; 28 patients also had vestibular symptoms. Eleven patients had vestibular symptoms only. Hearing loss was progressive in most, rapid in onset in one, and of sudden onset in two. Approximately 25% of patients had confirmed systemic autoimmune disease. Patients without systemic disease had serologic tests to confirm the diagnosis of AIED. The level of antinuclear antibodies was high, with a speckled pattern, in 38 patients, and 9 patients had a high rheumatoid factor. The positive yield of other detailed tests was low. Vestibular tests showed a peripheral type of change. Steroid treatment produced an excellent response in 33% and a good response in 16% without systemic disease. Only 25% of those with systemic disease had a similar response. Patients with vestibular symptoms only had an excellent response to steroids. Patients with AIED present with varied symptoms, and some have only vestibular symptoms. Limited serologic tests used in the diagnosis of systemic autoimmune diseases are valuable in establishing the diagnosis of AIED. Fifty percent of patients with AIED have an excellent response to steroids. Those with systemic disease have a lower response rate. Those with vestibular symptoms only are responsive to steroids.

Psychological Science, 1995

We describe a college student, A H, with a developmental deficit in determining the location of o... more We describe a college student, A H, with a developmental deficit in determining the location of objects from vision The deficit is selective in that (a) localization from auditory or tactile information is intact, (b) A H reports the identity of mislocalized objects accurately, (c) visual localization errors preserve certain parameters of the target location, and (d) visual localization is severely impaired under certain stimulus conditions, but nearly intact under other conditions These results bear on the representation and processing of location information in the visual system, and also have implications for understanding developmental dyslexia

Otology & Neurotology, 2003

... 3. Partial removal: up to 5% of the tumor left. ... This system therefore increases the chanc... more ... 3. Partial removal: up to 5% of the tumor left. ... This system therefore increases the chance of notreporting significant postoperative changes regarding the finer degrees of loss ... This classification also does not define normal and socially useful hearing, which should be considered ...

Otology & Neurotology, 2009

Neurology, 1997

Adrenomyeloneuropathy (AMN) is an X-linked metabolic disorder causing accumulation of very-long-c... more Adrenomyeloneuropathy (AMN) is an X-linked metabolic disorder causing accumulation of very-long-chain fatty acids with multifocal nervous system demyelination of the peripheral nerves, spinal cord, and cerebrum. The extent to which the disorder affects upper versus lower limbs or peripheral versus CNS has not been electrophysiologically defined in a large population nor differentiated in men and women. To determine patterns of nervous system demyelination and define gender differences, we studied 83 AMN patients with short latency median and posterior tibial nerve somatosensory evoked potentials (SSEPs). Most women (10/16) had abnormal median SSEPs all involving central pathways, whereas most men (59/67) had abnormal median SSEPs involving both peripheral and central pathways. Tibial SSEPs were abnormal in both sexes (14/15 women, 67/67 men), with either peripheral or central pathway involvement. This study demonstrates the frequent widespread involvement of both peripheral nerve an...

Neurology, 2002

Central vertigo can have positional characteristics that resemble the positional vertigo of perip... more Central vertigo can have positional characteristics that resemble the positional vertigo of peripheral origin.1 We observed a patient with vertigo that was triggered by orthostasis and likely caused by transiently impaired baroreflex function and cerebral autoregulation after a posterior inferior cerebellar artery (PICA) infarct. A 57-year-old man developed transient nausea, vomiting, vertigo, and diplopia that resolved within 10 minutes. Subsequently, he started to experience spells of intense vertigo every time he stood up. While supine, his blood pressure (BP) was 160/70 mm Hg, and his pulse was 65 beats/minute. The neurologic and neurotologic examination was unremarkable. Head- and neck-positioning maneuvers did not elicit any signs or symptoms. After standing up, however, BP dropped to 118/60 mm Hg, and pulse increased to 75 beats/minute. Within 20 to 30 seconds, he developed vertigo, left lateropulsion, and brisk right-beating horizontal nystagmus. The symptoms subsided within 20 seconds of recumbence. Brain MRI revealed an acute infarct in the right medial branch of PICA territory, involving the inferior cerebellum and the posterior medulla (figure, A). Cerebral angiography showed a right vertebral artery (VA) …

Neurologic Clinics, 2005

Management of dizzy patients depends on the history, bedside clinical examination, and laboratory... more Management of dizzy patients depends on the history, bedside clinical examination, and laboratory testing. The first two portions of this evaluation are covered in this article. The history is used to determine the onset of the problem, description of the symptoms, and, most importantly, how the symptoms affect the individual's lifestyle. This last element of the history is crucial, as some individuals may have evidence of chronic vestibular loss on one side based on clinical examination and laboratory testing, but they may be affected primarily by some other cause of dizziness, such as migraine or anxiety. The bedside clinical examination can be used to distinguish peripheral versus central vestibular problems, the degree of loss, and how acute the problem may be. History The history is the most important part of the evaluation. Taking a good history can be tedious, as complaints often are vague and frequently filled with anxiety-provoked symptoms. The tempo, symptoms, and circumstances of the complaint are three key items in the history (Table 1). Tempo Determine if patients have an acute attack of dizziness (3 days or fewer), chronic dizziness (more than 3 days), or spells of dizziness. Be sure to have patients describe the first onset of the dizziness. Did it happen suddenly or did it develop slowly? Was it provoked by anything or did it occur spontaneously? Did patients have a cold or some other illness near that time? If patients suffer from spells, try to determine the average duration of the spells in seconds, minutes, or hours. Have patients describe in detail the first spell, the most severe spell, and the last spell that they can recall clearly.

Medical Clinics of North America, 2003

Journal of the Neurological Sciences, 1997

Journal of Neuro-Ophthalmology, 1997

Afferent System Amaurosis Fugax, Shirley H. Wray Demyelinating Diseases: Optic Neuritis, Neil R. ... more Afferent System Amaurosis Fugax, Shirley H. Wray Demyelinating Diseases: Optic Neuritis, Neil R. Miller Low-Vision Rehabilitation in Neuro-Ophthalmology, Joseph L. Demer Diagnosis and Management of Idiopathic Intracranial Hypertension (Pseudotumor Cerebri), Kathleen B. Digre and James J. Corbett Syndromes of the Optic Chiasm, Saunders L. Hupp Color Vision Testing in Clinical Neuro-Ophthalmology, William M. Hart, Jr. Traumatic Optic Neuropathies, Thomas C. Spoor and John G. McHenry Nonarteritic Anterior Ischemic Optic Neuropathy, Shalom E. Kelman Optic Nerve Sheath Decompression, Robert C. Sergott Hereditary Optic Neuropathies, Nancy J. Newman Evaluation and Treatment of Pituitary Tumor, Mary Lee Vance Optic Nerve Gliomas: Treatment Differences for the Benign and Malignant Varieties, W. Bruce Wilson Efferent System Development of Congenital and Infantile Nystagmus, Robert D. Reinecke Management of Strabismus, Michael X. Repka Visual Symptoms of Otolith Dysfunction, G. M. Halmagyi and Ian S. Curthoys Management of Acquired Nystagmus and Oscillopsia, R. John Leigh Management of Congenital Nystagmus, L. F. Dell'Osso Neuro-Ophthalmic Implications of Vestibular Disorders, James A. Sharpe Management of Ocular Myasthenia Gravis, Daniel B. Drachman Diagnostic Workup and Management of Fourth Nerve Palsies, Edward G. Buckley Cavernous Sinus/Orbit Cavernous Sinus/Orbital Apex Syndrome, Lanning B. Kline Fine-Needle Aspiration Biopsy of the Orbit, Dennis C. Matzkin and Thomas L. Slamovits Cavernous Sinus Arteriovenous Fistula, Karl C. Golnik Idiopathic Orbital Inflammation (Pseudotumor), Phil A. Aitken Diagnosis and Management of Thyroid-Related Orbitopathy, Gregory S. Kosmorsky Technological Advances in Neuro-Ophthalmology Magnetic Resonance Angiography Relevant to Neuro-Ophthalmology, David I. Kaufman, James E. Siebert, and Joseph R. Pernicone Color Doppler Imaging of the Eye and Orbit, Wolfgang E. Lieb Pupil Perimetry, Randy H. Kardon Radiation-Induced Optic Neuropathy, John Guy and Norman J. Schatz Oculinum Therapy: Its Use in Neuro-Ophthalmology, Joseph A. Mauriello, Jr., Rudolph S. Wagner, Ramin Mostafavi, and Larry P. Frohman Pathology Neurosarcoidosis, Barney J. Stern and Cherie J. Sewell Internuclear Ophthalmoplegia, David S. Zee Neurological Paraneoplastic Syndromes, Robert W. Baloh Neuro-Ophthalmology of Mitochondrial DNA Diseases, Donald R. Johns and Kyle H. Smith Diseases of the Basal Ganglia, Christopher Kennard Progressive Supranuclear Palsy, Frederick E. Lepore Ocular/Neurosyphilis Update, J. Lawton Smith Neuro-Ophthalmic Lyme Disease in Perspective, Jacqueline M. S. Winterkorn Diagnosis, Diagnostic Pitfalls, and Treatment of Giant Cell Arteritis, Michael L. Slavin Vascular Insults-Eye Movements, B. Todd Troost Treatment of Headaches and Facial Pain, Robert B. Daroff and Christina M. Whitney-Rainbolt

Journal of Comparative Neurology, 1979

The location and retinotopic organization of areas 18 and 19 in cat cortex were determined using ... more The location and retinotopic organization of areas 18 and 19 in cat cortex were determined using electrophysiological mapping techniques. These two areas each contain a single representation of the visual hemifield and each has a distinctive cytoarchitecture. The visual hemifield representations in these two areas are nearly mirror images of each other. Compared to area 17, areas 18 and 19 have less cortical surface area, have a lower cortical magnification factor, contain less of the visual field and contain second order instead of first order transformations of the visual hemifield. An unusual asymmetry was found between the representations of the upper and lower visual quadrants not seen before in maps of other areas of cat or other species. A considerable amount of variability in the retinotopic organization of these two areas was found among cats.

Journal of Comparative Neurology, 1980

The retinotopic organization of cat cortex, in the vicinity of areas 20 and 21 as defined by Heat... more The retinotopic organization of cat cortex, in the vicinity of areas 20 and 21 as defined by Heath and Jones ('71), was determined using electrophysiological mapping techniques. Although the topography of the visual field representations in this region of cortex is more complex than that found in areas 17, 18, and 19, this region appears to contain four representations of the visual hemifield. The four cortical areas these visual field representations occupy have been labeled 20a, 20b, 21a, and 21b. These representations are not as precise as those found in areas 17, 18, and 19; the receptive fields in areas 20a, 20b, 21a, and 21b are larger and there is more scatter in receptive field location among adjacent cells. The upper visual hemifield is emphasized in all four of these areas, but the extent of the representation ranges from just the central 20° found in area 21a to nearly the entire upper visual quadrant found in area 20b. The peak areal magnification factors found in th...

Journal of Comparative Neurology, 1978

This is the second in a series of papers in which we describe our continuing efforts to define fu... more This is the second in a series of papers in which we describe our continuing efforts to define functional units of visual cortex based upon electrophysiological mapping of single and multiple unit activity in both awake and the nitrous oxide anesthetized cats. In the first paper (Tusa, Palmer and Rosenquist, '78), the extent and retinotopic organization of area 17 were described. In this paper, we describe the somewhat more complex organization of the visual cortex lying on the banks of the middle and posterior suprasylvian sulci. This region of cortex consists of six retinotopically organized units. These areas are arranged as three roughly mirror symmetrical pairs separated in each case by the fundus of the middle or posterior suprasylvian sulci. Some thalamo‐cortical autoradiographic material is presented which supports this parcellation of the cortex.