Nils R. Varney

Visual perception of line direction in patients with unilateral brain disease

The accuracy of identifying the slope of briefly exposed lines was assessed in patients with lesions of the left or right hemisphere and in a group of control patients without history or evidence of brain disease. The frequency of impaired performance was remarkably high in the patients with right hemisphere lesions. In contrast, the patients with left hemisphere lesions did not perform differently from the control group. Visual field defect, aphasic disorder, and age were not related to performance level. The striking interhemispheric difference in performance on this visuospatial task suggests its further development for clinicodiagnostic purposes.

Tactile perception of direction in relation to handedness and familial handedness.

Abstract The accuracy of tactile perception of the direction of tactile stimulation of brief duration applied to the palms of the hands was investigated in relation to hand preference and familial background in normal subjects. In confirmation of previous findings, perception of direction was significantly more accurate on the left hand than on the righthanded subjects. Lefthanded subjects showed no trend toward superior performance on either hand. Familial background in respect to handedness was found to be a significant and independent determinant of lateral pattern of performance. Righthanded subjects with a purely dextral familial background showed clear superiority on the left hand while those who had a lefthanded parent showed no lateral asymmetry in performance. Lefthanded subjects with righthanded parents show no lateral asymmetry in performance but those with a lefthanded parent show clear superiority on the right hand. The findings underscore the importance of familial background as a determinant of performances reflecting asymmetry in hemispheric function.

Lateral differences in tactile directional perception

Abstract Between-hands differences in the tactile perception of direction were assessed in normal righthanded subjects by a unimodal tactile matching task. The left hand superiority found in earlier studies employing a crossmodal tactile-visual matching procedure was again shown in this investigation. Thus the indications of hemispheric asymmetry in the mediation of tactile-spatial performances coming from studies which have utilized tactile-visual matching tasks cannot be ascribed to the crossmodal component in these tasks. The problem posed by the occurrence of “exceptional cases” in investigations of hemispheric asymmetry of perceptual function is raised.

Prognostic Significance of Anosmia in patients with Closed-Head Trauma

Among 40 patients who developed total anosmia as a result of closed-head injury, virtually all had major vocational problems during the two or more years after being medically cleared to return to work. None had major motor or sensory deficits, and the majority had above average intelligence and memory. However, most demonstrated psychosocial deficits of a type typically associated with damage to orbital frontal cortex. Vocational outcome for patients with partial anosmia was more variable with only about half having manifest vocational problems.

Quantitative PET findings in patients with posttraumatic anosmia.

OBJECTIVE To investigate quantitative positron emission tomography (PET) findings, particularly from orbitofrontal cortex, in patients with posttraumatic anosmia. SETTING Neuropsychology outpatient clinic and university brain imaging center. SUBJECTS Eleven patients with head injury resulting in severe anosmia and 11 controls matched for age. All 11 head-injured patients had their head injuries at least 2 years before involvement in the study. MEASURES Regional cerebral glucose metabolism was measured with PET. RESULTS Quantitative evaluation of PET findings for anosmic patients as a group showed orbitofrontal hypometabolism compared with controls. Decreased activity was also noted in mesial temporal lobe. Activity in subcortical white matter was essentially identical between groups. CONCLUSIONS Findings strongly suggest that posttraumatic anosmia is closely associated with hypometabolism in the orbitofrontal cortex and the medial prefrontal cortex. The results also underscore the importance of posttraumatic anosmia as a clinical sign of orbitofrontal damage, as has been shown previously with neuroSPECT (single photon emission computed tomography).

Tinker toy test performance and vocational outcome in patients with closed-head injuries.

Fifty patients who had suffered closed-head injury with no resultant physical disabilities and 25 normal controls were administered a modified version of Lezaks Tinker Toy Test. All head-injured patients were examined at least 24 months following medical clearance to return to work. Twenty-five of the head injured had been unable to return to work or sustain normal competitive employment as a result of their head injuries. The remaining 25 had returned to their previous jobs successfully or had been employed for at least 6 months prior to assessment. Whereas all but one of the head injured who returned to work scored normally on the Tinker Toy Test, nearly half of the nonreturnees performed below the level of the worst control.

NeuroSPECT correlates of disabling mild head injury: Preliminary findings

Objective: To study mild head injury patients with poor psychosocial and vocational outcomes using neurological single photon emission computed tomography (neuroSPECT) imaging. Design: Case‐comparison study. Setting: VA Medical Center, outpatient clinics. Patients: Fourteen mild head injury patients with normal computed tomography (CT) and/or magnetic resonance imaging (MRI) scans and five normal controls. Head‐injured patients were selected because they had obtained and maintained highly responsible employment prior to injury, but were unable to sustain any occupation despite multiple attempts over a number of years after injury. Intervention: NeuroSPECT with technetium Tc 99m hexamethylpropyleneamine oxime. Main Outcome Measure: Regional abnormalities in cerebral perfusion as indicated by neuroSPECT. Results: This carefully preselected population consistently showed anterior mesial temporal hypoperfusion. By contrast, posterior temporal abnormalities were very infrequent. NeuroSPECT findings with regard to orbitofrontal damage were not as striking, but were statistically significant on the left and were sufficient to raise the question of dysfunction in this area as well. Conclusions: Findings indicate that some “mild” head injuries with unusually catastrophic psychosocial consequences can produce regional abnormalities in cerebral perfusion that are apparent with neuroSPECT, even in the absence of abnormalities seen on CT or MRI.

Dichotic listening and complex partial seizures

This study reports on 24 patients with multiple symptoms of untreated complex partial seizures (CPSz) who performed poorly at baseline assessment on a brief dichotic word listening task and subsequently improved following successful anticonvulsant therapy directed at treating seizure symptoms. These preliminary findings suggest that, in the absence of macroscopic structural lesions, dynamic electrophysiological dysfunction may interfere with the processing and transmission of simultaneously presented auditory information.

CT Scan Correlates of Sound Recognition Defect in Aphasia

This study was concerned with the relationship between defects in sound recognition and intrahemispheric locus of lesion. Previous studies have shown that defects in sound recognition are common in association with left hemisphere lesions resulting in aphasias with comprehension deficits and are uncommon in association with other unilateral lesions. Current findings indicate that defects in sound recognition, occurring within the first month post onset of aphasia, may be associated with lesions of basal ganglia, the auditory cortex (both primary and association cortices), supramarginal gyrus, angular gyrus, and area 37. At the same time, however, a number of patients with lesions in these areas failed to show sound recognition defects.

Locus of lesion in impaired pantomime recognition.

This study was concerned with the relationship between intrahemispheric locus of lesion and defective pantomime recognition in a population of left hemisphere damaged aphasics. Defects in pantomime recognition appeared to result from lesions in basal ganglia and areas 40, 39, 37 and 22. At the same time, however, a significant minority of aphasics with lesions in these various loci did not show defects in pantomime recognition.