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Patients with Parkinson's disease (PD) often show impaired manual dexterity even when being only minimally bradykinetic, suggesting that they may have limb kinetic apraxia (LKA), that is, a loss of fine motor skill not explained by elemental motor deficits. To explore this dissociation, we investigated the differential dopaminergic responsiveness of dexterity and bradykinesia in PD. Twelve patients with PD (4 women, age 64.4 +/- 8.3, mean + SD) and 12 matched healthy controls (64.8 +/- 8.9) were tested twice in ON vs. OFF and 1st vs. 2nd trial, respectively. A coin rotation (CR) task was applied to assess dexterity and a finger tapping (FT) task to assess bradykinesia. Performance was followed by video recording and analyzed by measuring the frequency of CR and FT during three 10-second periods. Statistical analysis was done by a mixed factorial design with group (PD vs. controls) as between-subject factor and medication (ON- vs. OFF-state or 1st vs. 2nd trial), task (FT vs. CR), and handedness (dominant vs. nondominant) as within-subject factors. In patients with PD, regardless of hand involved, dopaminergic treatment only mildly improved CR performance, in contrast to the strong increase in FT scores (up to the level of controls), as demonstrated by the significant triple interaction of the factors group, medication, and task (F(1,22) = 7.9, P = 0.01; eta(2) = 0.26). Furthermore, CR scores were considerably lower, both in OFF and ON, than in normal controls, pointing to a substantial impairment of dexterity in PD (P < 0.001). In conclusion, impaired manual dexterity showing significantly diminished response to dopaminergic treatment suggests that dextrous deficits in PD are related to LKA rather than bradykinesia.

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We report what is to our knowledge the first approach to diamond turn microoptical lens array on a steep curved substrate by use of a voice coil fast tool servo. In recent years ultraprecision machining has been employed to manufacture accurate optical components with 3D structure for beam shaping, imaging and nonimaging applications. As a result, geometries that are difficult or impossible to manufacture using lithographic techniques might be fabricated using small diamond tools with well defined cutting edges. These 3D structures show no rotational symmetry, but rather high frequency asymmetric features thus can be treated as freeform geometries. To transfer the 3D surface data with the high frequency freeform features into a numerical control code for machining, the commonly piecewise differentiable surfaces are represented as a cloud of individual points. Based on this numeric data, the tool radius correction is calculated to account for the cutting-edge geometry. Discontinuities of the cutting tool locations due to abrupt slope changes on the substrate surface are bridged using cubic spline interpolation.When superimposed with the trajectory of the rotationally symmetric substrate the complete microoptical geometry in 3D space is established. Details of the fabrication process and performance evaluation are described.

Acute partial transverse myelitis (APTM) may be the first clinical manifestation of multiple sclerosis (MS), of relapsing myelitis, or remain a monophasic event. Identification of risk factors associated with relapse or conversion to MS is important, as prognostic information might help to guide management. The objective of this study was to define clinical, laboratory and neuroimaging factors in patients with first-ever APTM that predict relapses or conversion to MS. We identified 73 patients with a first-ever APTM admitted to our institution from January 1999 to June 2005. The follow-up time ranged from 12 to 90 months (mean follow-up 46 months). Patient demographics, clinical impairment at onset and after 3 months, ancillary tests including cerebrospinal fluid (CSF), magnetic resonance imaging (MRI), evoked potentials, recurrent and new symptoms and signs during follow-up were analysed. APTM remained a monophasic event in 35 patients (47.9%), conversion to MS occurred in 32 (43.8%) and recurred as relapsing myelitis in six patients (8.2%). According to univariate analysis, a family history of MS (P = 0.02), higher expanded disability status scale (EDSS) at onset (P = 0.03) and lesions on brain MRI (P = 0.03) were predictive factors for conversion to MS. CSF-specific oligoclonal bands (P = 0.04) or abnormal IgG-index (P = 0.04) were associated with increased risk for MS as well. In patients with a first-ever APTM, a family history of MS, high EDSS at presentation, lesions on brain MRI, CSF-specific oligoclonal bands or abnormal IgG-index may indicate an increased risk for conversion to MS.

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