MRI morphometry of the cerebral ventricles in patients with attention deficit hyperactivity disorder.

A total of 27 right-handed patients aged 7-30 years with diagnoses of attention deficit hyperactivity disorder were studied using standard MRI scans. Of these, 14 were aged below 13 years. The volumes of the lateral ventricles were measured using T1-weighted MRI images of sagittal sections of the brain to a precision of 3 mm3. External head sizes were also measured to allow ventricle volumes to be normalized. All patients underwent complex neuropsychological investigations. Memory was assessed, along with visual, auditory, tactile, and spatial recognition functions and the motor and speech spheres. Test data were assessed in terms of the severity of impairments associated with one brain structure or another on a tenpoint scale. Assessment points were summed for each hemisphere, for the "first area" (cortical structures), and all structures for statistical analysis. Neuropsychological testing revealed functional impairments predominantly of the frontal areas of the hemispheres, the hippocampus, and the reticular formation. Neuropsychological deficits were least linked with alterations in the postcentral and parietal areas of the cortex. Statistical analysis demonstrated a significant positive correlation between the normalized left lateral ventricle volume and the degree of neuropsychological impairments (r = 0.5127 at p = 0.0063) for the whole study group. The correlation was more marked on comparison of the normalized left ventricular volume and the severity of neuropsychological impairments related to the left hemisphere (r = 0.6303 at p = 0.0004). A relationship was seen between the volume of the intraventricular space and cortical functional impairments (r = 0.5071 at p = 0.0069) in patients less than 13 years old. A relationship between ventricular volume and linear head size was confirmed (r = 0.5759 at p = 0.0017), which was more marked in subjects less than 13 years old (r = 0.6833 at p = 0.01).

Observation of the naive-T-odd Sivers effect in deep-inelastic scattering.

Azimuthal single-spin asymmetries of leptoproduced pions and charged kaons were measured on a transversely polarized hydrogen target. Evidence for a naive-T-odd, transverse-momentum-dependent parton distribution function is deduced from nonvanishing Sivers effects for pi(+), pi(0), and K(+/-), as well as in the difference of the pi(+) and pi(-) cross sections.

[MRI morphometry of the brain ventricles in patients with attention-deficit hyperactivity disorder].

Twenty seven right-handed subjects aged 7-30 years with the attention deficit/hyperactivity disorder (ADHD) were exposed to standard MRI examination. From them, 14 were younger than 13 years old. The volumes of lateral ventricles were measured using T1-weighted MR-images of the sagittal brain sections to within 3 mm3. External head radii were measured additionally to normalize ventricle volumes. All patients passed complex neuropsychological testing. Memory and functions of visual, auditory, tactile and spatial recognition, motor and speech spheres were examined. Test results were evaluated by the degree of disorders with reference to corresponding brain structures on a 10-point scale. Absence of disorders corresponded to 0 points and maximum intensity of was scored as 10. Disorder scores were summed up for each of hemispheres, the first area (cortical structures), and all structures. Neuropsychological testing revealed disorders, predominantly, in the frontal area, hippocampus and reticular formation. Neuropsychological deficit was minimally related to the disturbances in post-central and parietal cortical areas. Statistical analysis revealed significant positive correlation between normalized volume of the left lateral ventricle and neuropsychological disorder score (r = 0.5127, p = 0.0063) for the whole group studied. The correlation between the normalized volume of the left lateral ventricle with the disorder score related to the left hemisphere was more significant (r = 0.6303, p = 0.0004). At the same time, a correlation of the ventricle volume and the dysfunction of the cortical structures was revealed (r = 0.5071, p = 0.0069) in subjects younger than 13 years old. The study corroborated interrelation between the volume of ventricles and linear head dimensions (r = = 0.5759, p = 0.0017) which was more pronounced in younger subjects (r = 0.6833, p = 0.01).

Double-hadron leptoproduction in the nuclear medium.

The first measurements of double-hadron production in deep-inelastic scattering within the nuclear medium were made with the HERMES spectrometer at DESY HERA using a 27.6 GeV positron beam. By comparing data for deuterium, nitrogen, krypton, and xenon nuclei, the influence of the nuclear medium on the ratio of double-hadron to single-hadron yields was investigated. Nuclear effects on the additional hadron are clearly observed, but with little or no difference among nitrogen, krypton, or xenon, and with smaller magnitude than effects seen on previously measured single-hadron multiplicities. The data are compared with models based on partonic energy loss or prehadronic scattering and with a model based on a purely absorptive treatment of the final-state interactions. Thus, the double-hadron ratio provides an additional tool for studying modifications of hadronization in nuclear matter.

Single-spin asymmetries in semi-inclusive deep-inelastic scattering on a transversely polarized hydrogen target.

Single-spin asymmetries for semi-inclusive electroproduction of charged pions in deep-inelastic scattering of positrons are measured for the first time with transverse target polarization. The asymmetry depends on the azimuthal angles of both the pion (phi) and the target spin axis (phi(S)) about the virtual-photon direction and relative to the lepton scattering plane. The extracted Fourier component sin((phi+phi(S))(pi)(UT) is a signal of the previously unmeasured quark transversity distribution, in conjunction with the Collins fragmentation function, also unknown. The component sin((phi-phi(S)(pi)(UT) arises from a correlation between the transverse polarization of the target nucleon and the intrinsic transverse momentum of quarks, as represented by the previously unmeasured Sivers distribution function. Evidence for both signals is observed, but the Sivers asymmetry may be affected by exclusive vector meson production.