Melissa A. Jenkins

Impairments of attention after cingulotomy

Background: Outcome studies have generally not indicated significant cognitive disturbances after cingulotomy. There is now considerable evidence that the cingulate may play an important role in emotional behavior and attention. Objective: To characterize impairments of attention associated with bilateral lesions of the anterior cingulate cortex produced by cingulotomy. Methods: Twelve patients who underwent cingulotomy for treatment of intractable pain were administered tests of attention, executive functions, response intention and production, and a broad range of other neurocognitive functions before surgery and again 3 and 12 months after surgery. Data from this within-subjects repeated-measures design were analyzed by multivariate analysis of variance procedures. Results: After cingulotomy, patients initially had executive and attentional impairments. By 12 months, these had resolved into more circumscribed deficits, with greatest impairments on tasks requiring intention and spontaneous response production, and milder impairments of focused and sustained attention. Other aspects of attention and other cognitive functions were generally unaffected. Conclusion: The anterior cingulate cortex modulates response intention and focused attention.

Attentional dysfunction associated with posttraumatic stress disorder among rape survivors.

Posttraumatic stress disorder (PTSD) is characterized by subjective reports of decreased concentration and an inability to sustain attention. Some empirical validation of these symptoms has been demonstrated via reduced performance on attentional tests among war veterans with PTSD. However, the significance of such findings is unclear given high co-morbidity with other psychiatric, neurologic, and substance abuse disorders among veterans. The present study examined neuropsychological functioning among rape survivors with PTSD, a patient population with comparatively low rates of psychiatric co-morbidity. Rape survivors with PTSD (PTSD+; n = 15) were compared to rape survivors without PTSD (PTSD–; n = 16) and age- and education-matched nontraumatized controls (CTRL; n = 16) on tests of attention. Performance of the PTSD+ group was significantly worse than the other groups on measures of sustained and divided attention, but not on shifting of visuospatial selective attention. Performance differences were not attributable to co-morbid psychiatric disorders or substance abuse. The implications of these findings regarding the effects of trauma on attentional functions are discussed.

The naming deficit in early Alzheimer's and vascular dementia

Patients with early Alzheimers disease (AD) were compared to normal controls and patients with early vascular dementia (VaD) on their naming errors using the Boston Naming Test (H. Goodglass & E. Kaplan, 1983). All naming errors were classified into three general error categories: visuoperceptual, semantic, and phonemic. Semantic errors were further classified into coordinate errors (responses that belong to the same semantic category as the target words), superordinate errors (responses that belong to a broader semantic category than the target word), and functional-circumlocutory errors (circumlocutions and responses that functionally describe the target word). The findings indicated that AD participants display more overall naming errors than VaD participants, although the pattern of general errors was similar between the patient groups. However, the qualitative difference between the patient groups was observed within the semantic errors because the AD group made more superordinate errors.

Dementia Rating Scale Performance: A Comparison of Vascular and Alzheimer's Dementia

Differences in the pattern of neuropsychological dysfunction associated with Alzheimers disease (AD) and vascular dementia (VaD) were examined using the Dementia Rating Scale (DRS). We examined three groups of patients: (1) Patients with AD; (2) patients with single stroke (CVA); and (3) patients with multiple cerebral infarctions (MI). Comparisons of cognitive dysfunction were conducted on patients that met the DRS criteria for dementia. Dementia groups were similar in age, education, and severity of dementia. Comparisons of the AD and two VaD groups across the specific DRS-scales (Attention, Conceptualization, Construction, Initiation/Perseveration, and Memory) indicated that patients with AD were more impaired on the DRS-Memory while the patients with VaD were more impaired on the DRS-Construction. Additionally, patients with VaD related to MI scored lower on the DRS-Initiation/Perseveration as compared to patients with AD, and patients with AD scored lower on the DRS-Conceptualization as compared to patients with VaD related to CVA. These results are indicative of qualitative differences in the pattern of cognitive deficits associated with the two types of dementia.

Memory processes in depressed geriatric patients with and without subcortical hyperintensities on MRI.

In this study, 12 patients over age 60 with depression with moderate to severe subcortical hyperintensities (SH) localized to the periventricular white matter were identified by quantitative MRI. Using the California Verbal Learning Test, they were compared with 12 age‐, education‐, and severity‐matched patients with depression with minimal white matter changes on specific aspects of memory performance. Patients with cortical lesions, neurologic or systemic illness affecting cognition, and history of substance abuse were excluded. Patients in the group with high SH showed reduced use of semantic encoding strategies (p < 0.05), reduced learning efficiency (p < 0.05), and a greater discrepancy between free recall and recognition discriminability (p < 0.05) than their low SH counterparts. This pattern of performance on memory tasks is similar to that found in previous studies to be associated with subcortical degenerative disorders such as Huntingtons and Parkinsons diseases. Geriatric patients with depression with SH may represent a subgroup with greater subcortical involvement, with associated cognitive and functional decline.

Disruption of short-duration timing associated with damage to the suprachiasmatic region of the hypothalamus

The neural bases of circadian rhythmicity have been demonstrated in a variety of animal species, including primates. Yet, the brain mechanisms underlying time experience and the timing of behaviors of shorter duration are still not well understood. In the present study, we demonstrate disruption of short-duration timing capacity in AH, a patient with damage to the suprachiasmatic (SCN) region of the hypothalamus. AH exhibited extreme inconsistency in her rate of tapping production on a motor continuation paradigm. Her inter-response intervals (IRIS) were extremely large compared with normal control subjects and were similar to those previously reported in patients with cerebellar dysfunction. Increased variability of both central timing and motor implementation processes was evident compared with both age-matched and elderly normal control subjects. Severe impairment of time perception was also evident on duration discrimination, whereas auditory loudness discrimination was intact. These findings suggest that a hierarchic relationship between long-duration (circadian) and short-duration timing exists, and that in addition to the cerebellum, intact hypo-thalamic functioning is necessary for short-duration timing.