Walking Before and During a Sea Voyage

Stationary and moving surfaces impose different constraints on walking. In this study we investigated within-participants differences between walking on a ship before (at the dock) and during (at sea) a sea voyage. Four individuals participated in the study. While on the ship they wore a tri-axial accelerometer (ActiGraph GT3X+; ActiGraph LLC, Pensacola, FL) on their waists. Activity data were sampled at 30 Hz. Data were collected on the day before the voyage began and on several days at sea. The number of steps per day was greater at the dock than at sea. The net resultant force per day also was greater at the dock than at sea. However, resultant force per step was greater at sea (79.97 ± 8.50 vector magnitude counts/step) than on land (62.94 ± 10.03 vector magnitude counts/step). In addition, we observed variations in resultant force per step across days at sea. Ship motion decreased overall activity but increased the force per step.     

Interhemispheric EEG activity in normal and aphasic adults.

EEG recordings were obtained from 10 normal and 10 aphasic adults while they participated in behavioral tasks and a no performance condition. Interhemispheric asymmetry and average activity at 5 to 15 Hz in each hemisphere were compared between groups and among tasks. Asymmetry during behavioral tasks did not differ significantly between groups or among tasks, however, aphasic patients showed a significant decrease in average activity at 5 to 15 Hz on the behavioral tasks compared with the level for a non performance condition. Test-retest reliability was poor for asymmetry but acceptable for average activity at 5 to 15 Hz. Finally, asymmetry was significantly related with severity of aphasia.     

The relationship of limb apraxia severity to motor and language deficits

Ipsilateral motor and symbolic/linguistic skills were examined in normals and three left hemisphere damaged groups with no, mild, or moderate-severe limb apraxia. When the two apraxic groups were pooled they demonstrated poorer response inhibition and reading relative to the nonapraxic group. There were no significant group differences on motor or language tasks when the three brain damaged groups were separately compared. These results indicate there is a limited relationship between limb apraxia and some motor and linguistic skills, but the relationship was not greater for motor than linguistic skills.     

The role of early maladaptive schemas in predicting exposure and response prevention outcome for obsessive-compulsive disorder

This is the first study that explores whether early maladaptive schemas are related to treatment outcome for patients with obsessive-compulsive disorder (OCD). The sample consisted of 88 outpatients with a diagnosis of OCD who completed exposure and response prevention treatment. The Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), the Beck Depression Inventory and Young Schema Questionnaire – Short Form were administered before and after treatment. Regression analyses using post-treatment Y-BOCS as the dependent variable indicated that higher scores on the abandonment schema at pre-treatment were related to poor outcome and explained 7% of the variance in symptoms at post-treatment. Higher scores on the self-sacrifice schema at pre-treatment were related to good outcome and explained 6% of the variance in obsessive-compulsive symptoms at post-treatment. During treatment, only changes in the failure schema were significantly related to good outcome and explained 18% of the variance in symptoms at post-treatment.     

The role of the hemispheres in closed loop movements

The purpose of these experiments was to determine if the two hemispheres play different roles in controlling closed loop movements. Subjects were asked to move to a narrow or wide target in the left or right hemispace. Reaction time (RT) was faster for the left arm of normals, only in the right hemispace, but there were no differences between arms in movement execution. Right but not left hemisphere stroke (CVA) patients showed longer RTs for the contralateral but not ipsilateral arm. The right CVA group's ipsilateral movement, especially to narrow targets was less accurate. The left CVA group's RT did not benefit from advanced information, but ipsilateral movement execution was normal. These results were discussed in terms of inter- as well as intrahemispheric control of programming and execution of closed loop movements.     

Skill learning in the elderly: diminished implicit and explicit memory for a motor sequence.

Explicit and implicit memory for a cognitive-motor sequence was studied in elderly and young adults. Implicit memory was examined in a serial reaction-time paradigm in which sequences of hand postures repeated cyclically, then shifted to random sequences. Two control groups received random sequences throughout. Movement times (MTs) across the first 4 blocks did not improve more in the elderly-repeated than in the elderly-random group. In contrast, the young-repeated group showed greater improvement in MT across these blocks than the young-random group. MT was less affected in the elderly than in the young by shifts between repeated and random sequences, indicating impaired implicit memory. Explicit memory, which was assessed by free recall and cued recall, also was impaired in the elderly. Diminished implicit memory in the elderly could not be explained solely by the possible intrusion of conscious recollection strategies.     

The different types of limb apraxia errors made by patients with left vs. right hemisphere damage

Limb apraxia errors were compared among normal controls and right- or left-hemisphere-damaged patients as they imitated gestures with the ipsilateral hand. Both brain-damaged groups made similar errors on nonrepresentative and representative/intransitive movements. In contrast for pretended object use movements (transitive), the left-hemisphere-damaged group made more arm position and classical body-part-as-object errors while the right hemisphere group made as many partial errors and more less-primitive, body-part-as-object errors than the left-hemisphere-damaged group. These results help explain why a certain percentage of right-hemisphere-damaged patients are labeled apraxic, but also suggest that the left hemisphere is more important for integrating intrapersonal space and the “representation” of extrapersonal space.     

Psychometric and CT scan measurements in a case of crossed aphasia in a dextral

A case of crossed aphasia with lesion deep to the right supramarginal gyrus was studied to determine (1) if this patient behaved similar to patients with the same lesion site in the left hemisphere, (2) if visuospatial deficits were present, and (3) if the CT scan asymmetries were similar to those of other right-handers. Speech and language skills were similar to those patients with similar lesions in the left hemisphere. Visuospatial and arithmetic deficits were similar to those described after right-hemisphere and left-hemisphere damage. CT scan asymmetries were atypical. These results provide behavioral and neuroradiological confirmation of atypical hemispheric dominance.     

Limb apraxia and motor performance

This study was desinged to determine if motor deficits in limb apraxia are task specific. Non-brain-damaged patients and apraxic and nonapraxic patients with left hemisphere damage performed language and limb apraxia tests and six motor tasks with the left hand. Contrary to previous data, no significant group differences occurred on a finger tapping task. Although task complexity or sequencing requirements affected group differences, greatest apraxic impairment was noted on a task of precise steadiness, but only when its response inhibition requirements were increased. This pattern of deficits appears to be associated with greater involvement of the premotor area in the apraxic group.