Gary Goldberg

Supplementary motor area structure and function : review and hypotheses

Though its existence has been known for well over 30 years, only recently has the supplementary motor area (SMA) and its role in the cortical organization of movement come to be examined in detail by neuroscientists. Evidence from a wide variety of investigational perspectives is reviewed in an attempt to synthesize a conceptual framework for understanding SMA function. It is suggested that the SMA has an important role to play in the intentional process whereby internal context influences the elaboration of action. It may be viewed as phylogenetically older motor cortex, derived from anterior cingulate periarchicortical limbic cortex, which, as a key part of a medial premotor system, is crucial in the “programming” and fluent execution of extended action sequences which are “projectional” in that they rely on model-based prediction. This medial system can be distinguished from a lateral premotor system postulated to have evolved over phylogeny from a different neural source. An anatomico-physiologic model of the medial premotor system is proposed which embodies the principles of cyclicity and reentrance in the process of selecting those neural components to become active in conjunction with the performance of a particular action. The postulated dynamic action of this model in the microgenesis of a discrete action is outlined. It is concluded that although there is a great deal to be learned about the SMA, a convergence of current evidence can be identified. Such evidence suggests that the SMA plays an important role in the development of the intention-to-act and the specification and elaboration of action through its mediation between medial limbic cortex and primary motor cortex.

Gender and arm length: Influence on nerve conduction parameters in the upper limb

Abstract Median, ulnar, and radial nerve conduction studies (NCS) were performed in 44 subjects. Students t -test was used to compare nerve conduction velocities (NCV), distal latencies (DL), and distal amplitudes (DAMP) for the two sexes. Only the sensory DAMPs showed statistical significance ( p 2 = .46, p 2 = .59, p 2 = .29, p

Statistical methods in rehabilitation literature: a survey of recent publications.

OBJECTIVE To document the use of statistical methods in the recent rehabilitation research literature. DESIGN Descriptive survey study. METHODS All 1,039 articles published between January 1990 and December 1993 in the American Journal of Physical Medicine and Rehabilitation and the Archives of Physical Medicine and Rehabilitation were reviewed for the use of statistical methods. RESULTS There were 682 (66%) research articles in the sample that included systematic data collection and analysis. The most frequently encountered analytic tests and techniques included: (1) analysis of variance, (2) t tests, (3) correlation analysis, (4) contingency table analysis, (5) regression, and (6) nonparametric tests. Results were compared with results of a review of the 1982 rehabilitation literature by Wainapel and Kayne. Our study showed an increased sophistication in statistical methodology as well as a more intense use of such methods. In addition, there was a large number of relatively obscure and poorly documented tests encountered in the more recent literature. There was also a lack of adherence to a standardized format for describing statistical methods. CONCLUSIONS The following recommendations are made: (1) Training curricula for rehabilitation professionals should provide instruction in the most commonly-encountered statistical methods and should be revised as needed to reflect changes in statistical method usage. (2) When less common statistical tests are applied, the responsibility of the authors to fully describe and justify their methods should be recognized. (3) Critical assessment of the literature is facilitated when statistical methods are reported in a standardized format.

Hemispatial factors in mirror writing

The effect of the hemispace in which writing was performed was assessed in two left hemisphere stroke patients who demonstrated left-handed mirror writing. Both patients produced significantly more mirrored words when writing in right, as compared to left (body) hemispace. We suggest that writing in the right hemispace activates the left hemisphere. Further, we propose that mirror writing in the right hemispace is attributable to activation of the damaged left hemisphere spatial system, which fails to assist in the translation of right hand motor programs into those appropriate to the left hand. Writing in left hemispace, in contrast, activates the intact right hemisphere based spatial system which guides the execution or monitoring of motor productions in left hemispace. The result is writing which remains directionally correct when the left hand is used in left hemispace.

Critical evaluation of clinical research

This focused review contains a suggested core of material that will help residents or practicing physiatrists critically review research papers published in the medical literature. Before accepting the results of a clinical trial, physiatrists must critique the experimental methods and study design carefully to decide whether to include these new ideas into their clinical practice. Medical research relies on statistical methodology, and statistics pervade the medical literature. This article begins with an introduction to rudimentary statistics. Fortunately, most studies depend on a rather small body of statistical concepts. The elements of experimental design--clinical trials, randomization, single-subject design, meta-analysis, epidemiological studies--are presented in a concise review. Finally, the elements of statistics and experimental design are integrated into a step-by-step method strategy for reading the medical literature.

Response and projection: a reinterpretation of the premotor concept

This paper reviews the principle of evolution of the neocortex which postulates that the neocortex has evolved over phylogeny from separate roots in hippo-campal and piriform cortices. In congruence with this principle, the premotor cortex of the frontal lobe of humans and subhuman primates is thought to be organized into two separate but interconnected systems—the mesiodorsal and the ventrolateral. The “core” premotor zone of the mesiodorsal system is the supplementary motor area (SMA) while that of the ventrolateral system is the arcuate premotor area (APA) identified in the primate brain. Evidence is presented to support the proposal that the SMA, as the premotor component of a system capable of generating model-based predictions, is necessary for extended, internally-contingent, project-ional action. The APA is hypothesized to be the premotor component of a system concerned with the perception, recognition and association of motivational significance to external inputs. It is postulated to be particularly important in the production of interactive, externally-contingent or responsive action.

AAEM case report 32 : Nerve injury associated with hip arthroplasty

Hip Arthroplasty to alleviate pain related to arthritic degeneration has become one of the most common orthopedic procedures performed. As the elderly population expands, the number of such procedures can be expected to continue to increase. An electrodiagnostic evaluation can aid in localization, help identify the mechanism of injury, and be used as a tool to identify the nature and severity of the nerve pathology. Electrodiagnosis can also be used to generate a prognosis for recovery from nerve damage following hip surgery.

Elements of academic productivity: A comparison of PM&R units versus other clinical science units

In early 1989, the Research Committee of the American Academy of Physical Medicine and Rehabilitation (AAPM&R) established a subcommittee to develop methods to monitor academic progress in physical medicine and rehabilitation (PM&R) units in the US. To develop an indirect baseline of academic productivity in PM&R, the rates and types of publications by PM&R researchers were assessed in eight peer review medical journals. The journals selected consisted of all issues of the following (published in calendar years 1987 to 1989): Archives of Physical Medicine and Rehabilitation, American Journal of Physical Medicine and Rehabilitation, Physical Therapy, Archives of Neurology, Pain, Stroke, Paraplegia, and Arthritis & Rheumatism. The sampling frame consisted of 3,553 journal articles. Affiliation with a PM&R unit or other clinical science unit (other unit), extramural funding sources, and type of manuscript (eg, case report or scientific investigation) were identified and coded. Sixteen percent of all articles were authored by members of PM&R units. The prevalence of scientific reports written by other unit authors (71%) was comparable to that written by PM&R authors (67%) (chi 2[3] = 5.54; p less than .20). There was a greater prevalence of funding by the US Department of Education of studies written by PM&R authors (10%) than of studies written by members of other units (2%) (chi 2[1] = 79.4; p less than .0001). Reports authored by members of other units had a greater prevalence rate of funding from all other sources--federal and private (47% vs 33%; chi 2[1] = 41.2; p less than .0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Neurophysiologic Models of Recovery in Stroke

A revised view of the CNS emphasizes the potential for experience to influence the detailed structure and function of the regions of the nervous system that are activated. The inherent plasticity in the synaptic organization of the brain and the response of synaptic organization to experience may provide a mechanism through which recovery of function following stroke can be understood. Basic studies in animal models may provide direction to the investigation and rehabilitation treatment of stroke patients.

The goal of treatment for motor impairment is not to “normalize” but to “functionalize” through facilitative modulation and enabling context

Adaptations occurring in the central nervous system (CNS) in the presence of pathology are not uniformly “good” for the organism when viewed in a functional context. A functional reordering of CNS priorities can be produced by allowing restructuring of the external context or through modification of neuromuscular physiology or anatomy designed to reduce the inherent restriction of functional movement in upper motor neuron syndrome. In fact, volitional control can often be “unmasked” through such interventions. Therapeutic interventions should not be directed toward “normalization” of motor patterns but should permit a functional reordering of CNS priorities that would otherwise not be possible.