Diagnostic validity of a short neurobehavioral test for screening of parietal lobe lesions

Disturbances stemming from lesions of the parietal lobes can produce the most wide-ranging and diagnostically ambiguous symptoms of any of the cortical regions. Currently, parietal assessment and research is hampered by the lack of a specific, brief battery which emphasizes sensory-perceptual rather than cognitive aspects of parietal lobe disease. The Neurological Tests of Parietal Impairment (NTPI) is a battery designed to fulfill this need, providing a broad but brief assessment of major neurobehavioral symptoms of parietal insult. The present study was a preliminary attempt to investigate the diagnostic validity of the NTPI, comparing 7 focal left and 7 focal right parietal lesion cases with 7 focal left and 4 focal right frontal lobe cases, and 5 cases with diffuse cortical disease. The NTPI was found correctly to lateralize right parietal patients and successfully to discriminate them from patients with both right and left frontal lesions on all NTPI subtests except those involving complex receptive speech. Diffuse lesion cases could not be differentiated from parietal patients on the NTPI, as expected. Left parietal patients were not correctly lateralized as effectively as right parietal cases by the NTPI, nor could their performance be differentiated from that of the frontal lesion cases. Possible reasons for this finding were discussed.