HUMAN SPINAL CORD IMPEDANCE: ITS APPLICATION IN NEUROSURGICAL STEREOTAXIC CORDOTOMY

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72600/1/j.1749-6632.1970.tb17740.x.pd

Identification of the Rostral Migratory Stream in the Canine and Feline Brain

In the adult rodent brain, neural progenitor cells migrate from the subventricular zone of the lateral ventricle towards the olfactory bulb in a track known as the rostral migratory stream (RMS). To facilitate the study of neural progenitor cells and stem cell therapy in large animal models of CNS disease, we now report the location and characteristics of the normal canine and feline RMS. The RMS was found in Nissl-stained sagittal sections of adult canine and feline brains as a prominent, dense, continuous cellular track beginning at the base of the anterior horn of the lateral ventricle, curving around the head of the caudate nucleus and continuing laterally and ventrally to the olfactory peduncle before entering the olfactory tract and bulb. To determine if cells in the RMS were proliferating, the thymidine analog 5-bromo-2-deoxyuridine (BrdU) was administered and detected by immunostaining. BrdU-immunoreactive cells were present throughout this track. The RMS was also immunoreactive for markers of proliferating cells, progenitor cells and immature neurons (Ki-67 and doublecortin), but not for NeuN, a marker of mature neurons. Luxol fast blue and CNPase staining indicated that myelin is closely apposed to the RMS along much of its length and may provide guidance cues for the migrating cells. Identification and characterization of the RMS in canine and feline brain will facilitate studies of neural progenitor cell biology and migration in large animal models of neurologic disease

Pain‐determined Dissociation Episodes

Objectives.  Dissociation disorders are a group of conditions characterized by a disruption of integrated function of consciousness, memory, or perception. The purpose of this report is to describe the impact of increased pain levels on the genesis of two types of dissociation disorders, dissociative fugue ( DF) and dissociative identity disorder ( DID), in patients with chronic pain ( PWCP). Design/Patients/Interventions/Outcome Measures. From November 1992 to July 2000, 2 DID and 4 DF patients were identified from 2,544 consecutive PWCP evaluated and/or treated at the University of Miami Comprehensive Pain and Rehabilitation Center. The salient features of these six dissociation PWCP are presented. All four DF PWCP completed a dissociation experience scale first at the time of identification of the dissociation disorder (with chronic pain) and one alleging their experiences with dissociation predevelopment of chronic pain. Results.  Frequency percentage for dissociation for this population was 0.235%. For all four of the DF PWCP, dissociation episodes began after the onset of chronic pain. All six (100%) PWCP described or associated their episodes of dissociation to times when their pain would increase. Mean dissociation scale scores for the four DF PWCP were 1.4 ± 1.11 pre‐chronic pain and 20.53 ± 16.82 at time of identification of the dissociative disorder (with chronic pain). Conclusions.  The frequency percentage for dissociation within PWCP is small compared with psychiatric populations. There may be an etiological association between the development of dissociation episodes and the development of chronic pain and/or increases in chronic pain

Is there a relationship between nonorganic physical findings (Waddell signs) and secondary gain/malingering?

This is a structured evidence based review of all available studies addressing the concept of nonorganic findings (Waddell signs) and their potential relationship to secondary gain and malingering. The objective of this review is to determine what evidence, if any, exists for a relationship between Waddell signs and secondary gain and malingering. Waddell signs are a group of 8 physical findings divided into 5 categories, the presence of which has been alleged at times to indicate the presence of secondary gain and malingering. A computer and manual literature search produced 16 studies relating to Waddell signs and secondary gain or malingering. These references were reviewed in detail, sorted, and placed into tabular form according to topic areas, which historically have been linked with the alleged possibility of secondary gain and malingering: 1) Waddell sign correlation with worker compensation and medicolegal status; 2) Waddell sign improvement with treatment; 3) Waddell sign correlation with Minnesota Multiphasic Personality Inventory validity scores; and 4) Waddell sign correlation with physician dishonesty perception. Each report in each topic area was categorized for scientific quality according to guidelines developed by the Agency for Health Care Policy and Research. The strength and consistency of this evidence in each subject area was then also categorized according to Agency for Health Care Policy and Research guidelines. Conclusions of this review were based on these results. There was inconsistent evidence that Waddell signs were not associated with worker's compensation and medicolegal status; there was consistent evidence that Waddell signs improved with treatment; there was consistent evidence that Waddell signs were not associated with invalid paper-pencil test; and there was inconsistent evidence that Waddell signs were not associated with physician perception of effort exaggeration. Overall, 75% of these reports reported no association between Waddell signs and the 4 possible methods of identifying patients with secondary gain and/or malingering. Based on the above results, it was concluded that there was little evidence for the claims of an association between Waddell signs and secondary gain and malingering. The preponderance of the evidence points to the opposite: no association