Hyperactive vestibulo-ocular reflex in cerebellar degeneration: pathogenesis and treatment

We studied a patient with a cerebellar degeneration and hyperactive vestibulo-ocular reflex (VOR). He complained of oscillopsia and blurred vision with head movement. A twofold increase in VOR gain (peak eye velocity/peak head velocity) at high frequencies was associated with a VOR time constant of 6 seconds (low normal). Visual cancellation ("suppression") of the VOR and smooth pursuit were also abnormal. We hypothesized that his high VOR gain was due to dysfunction of olivocerebellar projections. Physostigmine reduced his VOR gain, consistent with the hypothesis that these projections are cholinergic.     

Clinical and ocular motor analysis of congenital nystagmus in infancy.

PURPOSE: The purpose of this study was to identify the clinical and ocular motility characteristics of congenital nystagmus and to establish the range of waveforms present in infancy. BACKGROUND: The clinical condition of congenital nystagmus usually begins in infancy and may or may not be associated with visual sensory system abnormalities. Little is known about its specific waveforms in infancy or their relationship to the developing visual system. METHODS: Forty-three infants with involuntary ocular oscillations typical of congenital nystagmus were included in this analysis. They were evaluated both clinically and with motility recordings. Eye movement analysis was performed off line from both chart recordings and computer analysis of digitized data. Variables analyzed included age, sex, vision, ocular abnormalities, head position, null-zone or neutral-zone characteristics, symmetry, conjugacy, waveforms, frequencies, foveation times, and responses to convergence and to monocular cover. RESULTS: Patient ages ranged from 3 to 18 months (average, 9.2 months). Seventeen patients (40%) had abnormal vision, 3 had a positive family history of nystagmus, 11 had strabismus, 16 (37%) had a head posture, 26 (60%) had null and neutral positions, 14 (33%) had binocular asymmetry, and all were horizontally conjugate. Average binocular frequency was 2.8 Hz, and average monocular frequency was 4.6 Hz. The waveforms were both jerk and pendular; average foveation periods in patients with normal vision were more than twice as long as those in patients with abnormal vision. CONCLUSIONS: Common clinical characteristics and eye-movement waveforms of congenital nystagmus begin in infancy, and waveform analysis at this time helps with both diagnosis and visual status.     

Variable waveforms in downbeat nystagmus imply short-term gain changes

A patient with downbeat nystagmus subsequent to ankylosing spondylitis was studied. His nystagmus was found to exhibit both increasing- and decreasing-velocity exponential slow phases as well as the linear form more often reported. Alternation between waveforms sometimes occurred on a beat-to-beat or even intrabeat basis. Possible explanations for all three waveforms are presented in terms of short-term gain changes in cerebellar compensation for leaky brainstem neural integrators. A computer model was developed and its results are discussed.     

Paroxetine in Parkinson's disease: effects on motor and depressive symptoms

Selective serotonin reuptake inhibitors have been used in the treatment of depression in patients with PD. Conflicting data as to whether selective serotonin reuptake inhibitors worsen parkinsonian motor symptomatology have been reported. In this study, the additional 6 months therapy with paroxetine 20 mg/d in a group of depressed patients with PD did not modify parkinsonian motor function (Unified Parkinson's Disease Rating Scale scores); however, in one patient, fully reversible worsening of tremor was observed. Depression, as evaluated by Beck Depression Inventory and Hamilton Depression Rating Scale, improved from baseline to final visit (p < 0.05 by analysis of variance).     

Post-traumatic stress disorder in DSM-5: Estimates of prevalence and criteria comparison versus DSM-IV-TR in a non-clinical sample of earthquake survivors

Background

The latest edition of DSM (DSM-5) introduced important revisions to PTSD symptomatological criteria, such as a four-factor model and the inclusion of new symptoms. To date, only a few studies have investigated the impact that the proposed DSM-5 criteria will have on prevalence rates of PTSD.

Methods

An overall sample of 512 adolescents who survived the L'Aquila 2009 earthquake and were previously investigated for the presence of full and partial PTSD, using DSM-IV-TR criteria, were reassessed according to DSM-5 criteria. All subjects completed the Trauma and Loss Spectrum-Self Report (TALS-SR).

Results

A DSM-5 PTSD diagnosis emerged in 39.8% of subjects, with a significant difference between the two sexes (p<0.001), and an overall 87.1% consistency with DSM-IV-TR. Most of the inconsistent diagnoses that fulfilled DSM-IV-TR criteria but not DSM-5 criteria can be attributed to the subjects not fulfilling the new criterion C (active avoidance). Each DSM-5 symptom was more highly correlated with its corresponding symptom cluster than with other symptom clusters, but two of the new symptoms showed moderate to weak item-cluster correlations. Among DSM-5 PTSD cases: 7 (3.4%) endorsed symptom D3; 151 (74%) D4; 28 (13.7%) both D3 and D4; 75 (36.8%) E2.

Limitations

The use of a self-report instrument; no information on comorbidity; homogeneity of study sample; lack of assessment on functional impairment; the rates of DSM-IV-TR qualified PTSD in the sample was only 37.5%.

Conclusions

This study provides an inside look at the empirical performance of the DSM-5 PTSD criteria in a population exposed to a natural disaster, which suggests the need for replication in larger epidemiological samples.     

Dendritic cell precursor populations of mouse blood: identification of the murine homologues of human blood plasmacytoid pre-DC2 and CD11c+ DC1 precursors

Immature and predendritic cells (pre-DCs) of human blood are the most readily accessible human DC sources available for study ex vivo. Murine homologues of human blood DCs have not been described. We report the isolation and characterization of 2 populations of precursor DCs in mouse blood. Mouse blood cells with the surface phenotype CD11c(lo)CD11b(-)CD45RA(hi) closely resemble human plasmacytoid cells (or pre-DC2) by morphology and function. On stimulation with oligonucleotides containing CpG motifs (CpG), these cells make large amounts of type 1 interferons and rapidly develop into DCs that bear CD8, though they may be distinct from the CD8(+) DCs in the unstimulated mouse. A second population of cells with the surface phenotype CD11c(+)CD11b(+)CD45RA(-) closely resembles the immediate precursors of pre-DC1, rapidly transforming into CD8(-) DCs after tumor necrosis factor-alpha (TNF-alpha) stimulation. These findings indicate the close relationship between human and mouse DCs, provided cells are obtained directly from equivalent source materials.     

Combining recessions (nystagmus and strabismus) with tenotomy improved visual function and decreased oscillopsia and diplopia in acquired downbeat nystagmus and in horizontal infantile nystagmus syndrome.

PURPOSE: To investigate the effects of combined tenotomy and recession procedures on both acquired downbeat nystagmus and horizontal infantile nystagmus. METHODS: Patient 1 had downbeat nystagmus with a chin-down (upgaze) position, oscillopsia, strabismus, and diplopia. Asymmetric superior rectus recessions and inferior rectus tenotomies reduced right hypertropia and rotated both eyes downward. Patient 2 had horizontal infantile nystagmus, a 20 degrees left-eye exotropia, and alternating (abducting-eye) fixation. Lateral rectus recessions and medial rectus tenotomies were performed. Horizontal and vertical eye movements were recorded pre- and postsurgically using high-speed digital video. The eXpanded Nystagmus Acuity Function (NAFX) and nystagmus amplitudes and frequencies were measured. RESULTS: Patient 1: The NAFX peak moved from 10 degrees up to primary position where NAFX values improved 17% and visual acuity increased 25%. Vertical NAFX increased across the -10 degrees to +5 degrees vertical range. Primary-position right hypertropia decreased approximately 50%; foveation time per cycle increased 102%; vertical amplitude, oscillopsia, and diplopia were reduced, and frequency was unchanged. Patient 2: Two lateral, narrow high-NAFX regions (due to alternating fixation) became one broad region with a 43% increase in primary position (acuity increased approximately 92.3%). Diplopia amplitude decreased; convergence and gaze holding were improved. Primary-position right exotropia was reduced; foveation time per cycle increased 257%; horizontal-component amplitude decreased 45.7%, and frequency remained unchanged. CONCLUSIONS: Combining tenotomy with nystagmus or strabismus recession procedures increased NAFX and visual acuities and reduced diplopia and oscillopsia in downbeat nystagmus and infantile nystagmus.