Biomedical subjects

Teresa C Frohman

Publications and source records attributed to Teresa C Frohman.

6 recordsLinked to original sources

PubMed2006

Relation of visual function to retinal nerve fiber layer thickness in multiple sclerosis.

PURPOSE: To examine the relation of visual function to retinal nerve fiber layer (RNFL) thickness as a structural biomarker for axonal loss in multiple sclerosis (MS), and to compare RNFL thickness among MS eyes with a history of acute optic neuritis (MS ON eyes), MS eyes without an optic neuritis history (MS non-ON eyes), and disease-free control eyes. DESIGN: Cross-sectional study. PARTICIPANTS: Patients with MS (n = 90; 180 eyes) and disease-free controls (n = 36; 72 eyes). METHODS: Retinal never fiber layer thickness was measured using optical coherence tomography (OCT; fast RNFL thickness software protocol). Vision testing was performed for each eye and binocularly before OCT scanning using measures previously shown to capture dysfunction in MS patients: (1) low-contrast letter acuity (Sloan charts, 2.5% and 1.25% contrast levels at 2 m) and (2) contrast sensitivity (Pelli-Robson chart at 1 m). Visual acuity (retroilluminated Early Treatment Diabetic Retinopathy charts at 3.2 m) was also measured, and protocol refractions were performed. MAIN OUTCOME MEASURES: Retinal nerve fiber layer thickness measured by OCT, and visual function test results. RESULTS: Although median Snellen acuity equivalents were better than 20/20 in both groups, RNFL thickness was reduced significantly among eyes of MS patients (92 mum) versus controls (105 mum) (P<0.001) and particularly was reduced in MS ON eyes (85 mum; P<0.001; accounting for age and adjusting for within-patient intereye correlations). Lower visual function scores were associated with reduced average overall RNFL thickness in MS eyes; for every 1-line decrease in low-contrast letter acuity or contrast sensitivity score, the mean RNFL thickness decreased by 4 mum. CONCLUSIONS: Scores for low-contrast letter acuity and contrast sensitivity correlate well with RNFL thickness as a structural biomarker, supporting validity for these visual function tests as secondary clinical outcome measures for MS trials. These results also suggest a role for ocular imaging techniques such as OCT in trials that examine neuroprotective and other disease-modifying therapies. Although eyes with a history of acute optic neuritis demonstrate the greatest reductions in RNFL thickness, MS non-ON eyes have less RNFL thickness than controls, suggesting the occurrence of chronic axonal loss separate from acute attacks in MS patients.

Acute Disease↗

PubMed2005

The neuro-ophthalmology of multiple sclerosis.

Multiple sclerosis (MS) is the most common disabling neurological disease in young people. Most CNS lesions involve neuroanatomically non-eloquent zones that often do not result in symptomatic complaints. By contrast, tissue-injury mechanisms involving inflammatory demyelination can involve more eloquent sites, such as the optic nerve and brainstem, which can correspondingly produce the development of well recognised syndromes such as optic neuritis and internuclear ophthalmoplegia, respectively. In this review we discuss the broad landscape of abnormalities that affect the afferent visual system and the ocular motor apparatus, and emphasise relevant features, the recognition and treatment of which are of importance to general neurological practice. The commonness of visual sensory and eye movement abnormalities in MS highlights the importance of understanding the principles addressed in this review.

Humans↗

PubMed2004

An unusual variant of the dorsal midbrain syndrome in MS: clinical characteristics and pathophysiologic mechanisms.

Patients with MS exhibit a broad diversity of ocular motor syndromes. We describe a patient with relapsing-remitting MS who developed an unusual variation of the dorsal midbrain syndrome, characterized by monocular convergent-retraction nystagmus in the right eye, accompanied by divergent-retraction nystagmus in the fellow eye upon attempted upward gaze. Examination also revealed a skew deviation with a left hyperdeviation and severe adduction limitation in the left eye during attempted right gaze. We propose that a left INO accounted for the inability of the left eye to adduct (and result in convergent-retraction) during attempted upward saccades. We consider the pathophysiologic mechanisms responsible for our observations and review important details of the dorsal midbrain ocular motor circuitry.

Adult↗

PubMed2003

A new measure of dysconjugacy in INO: the first-pass amplitude.

BACKGROUND: The ratios of abducting to adducting eye movements (versional dysconjugacy index, VDI) for saccadic velocity and acceleration have been useful measures by which to objectively characterize internuclear ophthalmoparesis (INO). Amplitude measures of dysconjugacy have been less useful, given that many patients maintain the ability to ultimately reach a centrifugal fixation target and that traditional amplitude measures of VDI have focused on this 'final amplitude' (FA) position. METHODS: We utilized infrared oculography to define a new amplitude measure of dysconjugacy in 42 multiple sclerosis (MS) patients with INO. The first-pass amplitude (FPA)-VDI is the ratio of abduction/adduction eye movement amplitudes computed at the time when the abducting eye initially achieves the centrifugal horizontal fixation target. RESULTS: FPA-VDI values were significantly more sensitive and specific than FA-VDI values in demonstrating dysconjugacy in INO, and there was a 14-fold increase in dysconjugacy as measured by FPA-VDI Z-scores when compared to FA-VDI Z-scores. CONCLUSION: Consideration of velocity (pulse) and amplitude (step) components of dysconjugacy in patients with INO can provide a greater understanding of the dynamic aspects of this syndrome. We propose to characterize the relationship between the pathophysiology of INO and neuroradiologic measures of tissue injury in MS.

Diagnostic Techniques, Ophthalmological↗

PubMed2003

Horizontal monocular saccadic failure: an unusual clinically isolated syndrome progressing to multiple sclerosis.

This paper describes an unusual clinically isolated syndrome of inflammatory demyelination that was characterized by a right VI nerve palsy and right internuclear ophthalmoparesis (INO), along with an unusual form of dissociated nystagmus. Magnetic resonance imaging (MRI) revealed an isolated lesion within the right dorsomediolateral pontine tegmentum. Four years later, the subject developed a partial sensory transverse myelitis, confirming clinically definite multiple sclerosis (MS). This paper extends the range of isolated syndromes associated with MS.

Abducens Nerve Diseases↗

PubMed2002

Acquired sexual paraphilia in patients with multiple sclerosis.

BACKGROUND: Sexual dysfunction in patients with multiple sclerosis is typically characterized by diminished libido, erectile and ejaculatory dysfunction in men, and poor lubrication and anorgasmy in women. In contrast, hypersexual behavior and paraphilias are distinctly uncommon in this population of patients, but have been associated with various focal brain lesions. PATIENT AND METHODS: We describe a man with clinically definite multiple sclerosis who developed profound and abrupt disinhibition and paraphilic behavior during an exacerbation. RESULTS: Neuroimaging revealed a marked increase in the number of enhancing lesions in the right sides of the hypothalamus and mesencephalon and extending into the right sides of the red nucleus, substantia nigra, and internal capsule. The altered sexual behavior was characterized by an obsessive and insatiable desire to touch women's breasts. CONCLUSIONS: Acquired sexual paraphilic behavior is uncommon in patients with multiple sclerosis but may occur when inflammatory demyelination involves the hypothalamic and septal regions of the basal prosencephalon. Our experience with this man illustrates the great difficulty involved in treating such patients when the paraphilic behavior becomes persistent.

Adult↗