Neuropsychological Sequelae of Subthalamic Nucleus Deep Brain Stimulation in Parkinson's Disease: A Critical Review

Neuropsychologists are increasingly involved in surgical candidacy evaluations and postoperative neurobehavioral assessments of patients with movement disorders, most notably those with disease (PD). We review here the initial studies regarding neuropsychological outcomes of deep brain stimulation (DBS) within the subthalamic nucleus (STN) for treatment of PD. Overall, these initial investigations provide preliminary support for the cognitive and neurobehavioral safety of STN DBS. Improvements in self-reported symptoms of depression and diminished verbal fluency were the most common findings, whereas changes in global cognitive abilities, memory, attention, and frontal/executive functions were inconsistent and most often described as nominal and/or transient. The generalizability of this literature is hindered by several methodological limitations, including small samples and the absence of appropriate control participants. The clinical and theoretical implications of these initial studies are highlighted and recommendations are offered to guide future research.     

Action verbal fluency normative data for the elderly

An emerging body of literature points to the prominent role of the frontal lobes in the retrieval of verbs, whereas production of common and proper nouns arguably is mediated primarily by posterior and anterior temporal regions, respectively. Although the majority of studies examining the neuroanatomic distinctions between verb and noun retrieval have relied on action naming tasks (naming depicted activities, e.g., running) as indicators of verb retrieval abilities, recent studies have utilized an action (verb) verbal fluency measure, the Action Fluency Test (AFT), to assess verb retrieval. Findings from these studies suggest that action fluency is sensitive to the integrity of fronto-subcortical neural circuitry and that it is a valid measure of executive and language functions. The AFT is an easily administered executive function measure, but no normative data for the AFT or other action fluency tasks has been published. This study was undertaken to provide initial AFT normative data for a sample of 145 healthy elderly subjects. As education is significantly correlated with AFT scores, the normative data are stratified by educational level.     

Fathers’ and Mothers’ Involvement with Their Adolescents

We explored mothers’ and fathers’ time spent with their adolescents and found that mothers reported spending more time with their adolescents than did fathers. Developmental patterns were found for some aspects of time involvement, with both mothers and fathers reporting higher involvement with younger adolescents. Ratings of time-spent were not associated with adolescents’ self-reported emotional/behavioral problems. Both mothers and fathers agreed that mothers had more responsibility for adolescents’ discipline, daily care, and recreational activities. Mothers and fathers reported comparable levels of satisfaction with this arrangement. Mothers, and to a lesser extent fathers, reported greater satisfaction with the division of labor when fathers showed higher levels of responsibility for adolescents’ activities. Satisfaction with the division of labor was inversely related to interparental conflict. Few differences were found based on adolescent gender for any of these variables. Results are discussed within the context of mother–child and father–child relationships and family functioning.     

A Comparison of Multidimensional Health Profiles across Three Trauma-Exposed Diagnostic Groups

Posttraumatic stress disorder has been associated with adverse health outcomes. The extent to which the health effects of PTSD differ from other diagnoses has not been explored empirically. The current study investigated the Multidimensional Health Profile (including both Psychosocial and Health factors), across three diagnostic groups and one group of well-adjusted participants (N = 92) in a contrasted-groups design. Participants were all trauma-exposed and were assessed using structured clinical interviews. The PTSD and depression groups tended to differ from the social phobia and well-adjusted groups. Both the PTSD and depression groups demonstrated elevated profiles on variables assessing psychological distress, negative social exchange, and hypochondriasis. Results are consistent with prior research suggesting PTSD is associated with worse psychological and health functioning relative to trauma-exposed individuals without PTSD, although these health outcomes seem to differ little between those with PTSD and those with depression.     

Motion as manipulation: implementation of force–motion analogies by event-file binding and action planning

Tool-improvisation analogies are structure-mapping inferences implemented, in many species, by event-file binding and pre-motor action planning. These processes act on multi-modal representations of currently perceived situations and eventuate in motor acts that can be directly evaluated for success or failure; they employ implicit representations of force-motion relations encoded by the pre-motor system and do not depend on explicit, language-like representations of relational concepts. A detailed reconstruction of the analogical reasoning steps involved in Rutherford's and Bohr's development of the first quantized-orbit model of atomic structure is used to show that human force-motion analogies can in general be implemented by these mechanisms. This event-file manipulation model of the implementation of force-motion analogies is distinguished from the standard view that structure-mapping analogies require the manipulation of explicit, language-like representations of relational concepts.     

Visual re-identification of individual objects: a core problem for organisms and AI

Two open questions about the visual re-identification of individual objects over extended time periods are briefly reviewed: (1) How much a priori information about the nature of objects, identity and time is required to support robust individual object re-identification abilities? and (2) how do epistemic feelings, such as the feeling of familiarity, contribute both to object re-identification and to the perception of opportunities and risks associated with individual objects and their affordances? The ongoing interplay between experiments that can be carried out with human subjects and experiments made possible with robotic systems is examined. It is suggested that developmental robotics, including virtual-reality simulations of robot–environment interactions, may provide the best route to understanding both the implementation of epistemic feelings in humans and their functional contribution to the identification of persistent individual objects.     

The effects of differential training procedures on linked perceptual class formation

When the stimuli in one perceptual class (A') become related to the stimuli in another perceptual class (B'), the two are functioning as a single linked perceptual class. A common linked perceptual class would be the sounds of a person's voice (class A') and the pictures of that person (class B'). Such classes are ubiquitous in real world settings. We describe the effects of a variety of training procedures on the formation of these classes. The results could account for the development of naturally occurring linked perceptual classes. Two perceptual classes (A' and B') were formed in Experiment 1. The endpoints of the A' class were called anchor (Aa) and boundary (Ab) stimuli. Likewise, the anchor and boundary stimuli in the B' class were represented as Ba and Bb. In Experiment 2, the A' and B' classes were linked by the establishment of one of four cross-class conditional discriminations: Aa-->Ba, Aa-->Bb, Ab-->Ba, or Ab-->Bb. Results were greatest after Aa-->Bb training, intermediate after Aa-->Ba and Ab-->Ba training, and lowest after Ab-->Bb training. Class formation was influenced by the interaction of the anchor/boundary values and the sample/comparison functions of the stimuli used in training. Experiment 3 determined whether class formation was influenced by different sets of two cross-class conditional discriminations: Aa-->Ba and Ab-->Bb, or Aa-->Bb and Ab-->Ba. Both conditions produced equivalent results. Similarities were attributable to the use of anchor stimuli as samples and boundary stimuli as comparisons in each training condition. Finally, the results afterjoint Aa-->Ba and Ab-->Bb training were much greater than those produced by summing the results of Aa-->Ba training alone and Ab-->Bb training alone. This same synergy was not observed after joint Aa-->Bb and Ab-->Ba training or either alone.