Biomedical subjects

T Grabowski

Publications and source records attributed to T Grabowski.

At least 19 recordsLinked to original sources

PubMed2003

Improvement in variability of the horizontal meridian of the primary visual area following high-resolution spatial normalization.

We investigated the decrease in intersubject functional variability in the horizontal meridian (HM) of the primary visual area (V1) before and after individual anatomical variability was significantly reduced using a high-resolution spatial normalization (HRSN) method. The analyzed dataset consisted of 10 normal, right-handed volunteers who had undergone both an O-15 PET study, which localized retinotopic visual area (V1), and a high-resolution anatomical MRI. Individual occipital lobes were manually segmented from anatomical images and transformed into a common space using an in-house high-resolution regional spatial normalization method called OSN. Individual anatomical and functional variability was quantified before and after HRSN processing. The reduction of individual anatomical variability was judged by the reduction in gray matter (GM) mismatch and by the improvement in overlap frequency between individual calcarine sulci. The reduction in intersubject functional variability of HM was determined by measurements of the overlap frequency between individual HM areas and by improvement in intersubject Z-score maps. The HRSN processing significantly reduced the individual anatomical variability: GM mismatch was reduced by a factor of two and the mean calcarine sulcus overlap frequency was improved from 37 to 68%. The reduction in functional variability was more subtle. However, both HM mean overlap (increased from 18 to 28%) and the average Z-score (increased from 2.2 to 2.55) were significantly improved. Although, functional registration was significantly improved by matching sulci, there was still residual variability. This is believed to be the variability of individual areas within the calcarine sulcus, and cannot be resolved by sulcal match. Thus, the proposed methodology provides an efficient, unbiased, and automated way to study structure-functional relationship in human brain.

Brain↗

PubMed1998

A case of late-onset MELAS.

We describe a 60-year-old man with MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes) and discuss the mitochondrial DNA point mutation 3243. A diagnosis of MELAS should be considered in the appropriate clinical setting at any age.

Age of Onset↗

PubMed1994

The return of Phineas Gage: clues about the brain from the skull of a famous patient.

When the landmark patient Phineas Gage died in 1861, no autopsy was performed, but his skull was later recovered. The brain lesion that caused the profound personality changes for which his case became famous has been presumed to have involved the left frontal region, but questions have been raised about the involvement of other regions and about the exact placement of the lesion within the vast frontal territory. Measurements from Gage's skull and modern neuroimaging techniques were used to reconstitute the accident and determine the probable location of the lesion. The damage involved both left and right prefrontal cortices in a pattern that, as confirmed by Gage's modern counterparts, causes a defect in rational decision making and the processing of emotion.

Accidents, Occupational↗

PubMed1992

Leptomeningeal myelomatosis presenting with mental status changes and other neurologic findings.

BACKGROUND: Leptomeningeal myelomatosis is a rare complication of multiple myeloma. METHODS: The authors identified and studied three patients with leptomeningeal myelomatosis and reviewed previous case reports of this condition. RESULTS: The patients described here had intermittent abnormalities in mental status or cranial nerve and brain stem abnormalities. Two of the patients responded dramatically, though transiently, to treatment. In one patient, the clinical findings correlated with lesions visualized by gadolinium-enhanced magnetic resonance imaging. CONCLUSIONS: These patients are typical of those reported previously. Patients with leptomeningeal myelomatosis often have a good response to treatment initially, but long-term survival is rare.

Aged↗

PubMed1992