Sidney Weinstein

TACTILE SENSITIVITY OF THE PHALANGES

Recent publications have reported a consistent superiority of the left side of the body for sensation of pressure (Ghenr, 19G1; Semmes, Weinsrein, Ghenr, & Teuber, 1960; Weinstein, in press; Weinsrein & Sersen, 1961) or electrical stimuli (Green, Reese, Peques, & Elliott, 1961) in dextrals. Also reported to influence sensitiviry, at least for two-point discrimination, is the degree of distal ir~ from the trunk, and, concomitantly, the relative motility of the part (Vierordr, 1870; Weber, 1900). Two-point discrimination thresholds were reported to diminish continuously from upper arm to the distal phalanges. The purpose of the present study was to determine whether a proximal-distal relationship exists with reyard to cutaneous pressure sensitivity of the phalanges, and whether the right-left d~fferences previously reported for palms, forearms, upper arms, soles, and breasts n-ould also be obtained in the fingers.

Phantoms in cases of congenital absence of limbs.

ALTHOUGH THE PHANTOM LIMB has been described for some four centuries as the subjective awareness of a nonexistent or deafferented appendage, to the authors’ knowledge there have been no reports of phantoms in cases of congenital absence of limb. In fact, most authors, starting with Pick,’ deny the possibility of phantoms in cases of congenital absence of limb or where the amputation occurs during the first five years of life. The usual explanation of such absence of phantom is derived from the theoretic positions of Pick,’ Head,* and Bonnier.3 Thus, for example, in describing a case of congenital absence of the forearm with no experience of phantom limb, Bailey and Moersch4 state: “This would be expected since sensory impression for this part had never been recorded by the cerebral cortex.” Browder and Gallaghe+ say of congenital absence of limb that I ‘ . . . there would not be a phantom of the missing part since it was never included in the normal body pattern.” In discussing the case of congenital absence of limbs, Kolbe maintains: “In such cases, the continuing barrage of sensory impressions either has not existed or has been of too short duration to allow the development of this body concept.” During the course of an investigation to determine somatosensory changes in loss or absence of limbs, 30 patients with cases of congenital absence of limb were examined. Since the routine procedure in the examination of all patients requires the administration of a questionnaire concerning the presence and type of phantom, this series of questions was also administered to the patients with congenital absences. The authors were quite surprised to discover the presence of phantom limbs in 5 of the 30 patients. This report describes the patients with such phantoms, discusses the reasons it is believed phantoms have never been reported in such cases before, and the implications of these findings.

IS REAFFERENCE NECESSARY FOR VISUAL ADAPTATION

Two studies were performed to determine the necessity of reafference (stimulation due to self-induced movement) in the production of adaptation to prismatic displacement. In Exp. I, 48 Ss exposed to laterally-displacing prisms, were equally divided into four groups comprising combinations of each of the two following variables: self-induced versus passive movement, and self-directed versus externally-directed motion. These groups were non-differential in the magnitude of positive adaptation, although the total population adapted positively and significantly to the prisms. In Exp. II, 17 Ss were tested before and after exposure to the same prisms in a situation which provided informational feedback regarding error and which eliminated self-produced movement. The group demonstrated significant positive adaptation. It is concluded that reafference is not necessary for adaptation and that informational feedback is, at least, sufficient and may be necessary for adaptation.

Phantoms and Somatic Sensation in Cases of Congenital Aplasia

Summary Data are presented from interviews with 101 cases of congenital aplasia. Hand strength and finger dexterity were studied in 44 of these cases with unilateral upper extremity aplasia. Pressure, two-point, and point localization thresholds were obtained on the stump, homologous area, and palm in 27 of the cases with upper extremity aplasia. 1. Thirteen new cases of phantoms in congenital aplasics are described in addition to the five previously reported. 2. The characteristics of the phantoms obtained in the present population of congenital aplasics agree with those previously reported. 2. Terminal aplasics tend to have a higher incidence of phantoms than do intercalary aplasics, a finding consistent with greater cortical representation of such parts. 2. Phantoms acquired after amputation of deformities resemble the deformity, a finding inconsistent with theories based on phantasy. 2. Although use of prostheses is unrelated to strength, fitting a prosthesis before the age of seven significantly enhances the probability of phantom occurrence in congenital aplasics. 2. Strength and coordination of the right and left hands do not differ in cases of unilateral aplasia. 2. The tactual sensitivity of the stump equals that of the palm, and exceeds that of its homologous region. The implications of these findings are discussed with regard to theories of phantom causation and brain function.

Deficits Concomitant with Aphasia or Lesions of Either Cerebral Hemisphere

Summary Recent research has demonstrated several sensory, perceptual, cognitive, and motor deficits which are concomitant with, or are spared in aphasia, or lesions of either cerebral hemisphere. Concomitant impairments in aphasia . Studies of aphasics and non-aphasic brain-injured subjects revealed impairment specific to the aphasic for tests involving: knowledge of the body (body schema), ability to locate embedded geometrical figures (hidden figures), complex visual problem-solving ability (conditional reaction), and map-reading with path-findings (spatial orientation). Impairments specific to right or left hemispheres . Brain-injured subjects with lesions of the right hemisphere were significantly poorer than controls or those with left hemisphere lesions on: tactual three-dimensional size discrimination, tactual discrimination of form, and speed of index finger oscillation. Those with lesions of the left parieto-temporal region showed a significant decline in general intelligence. Elimination of the aphasics from this comparison did not modify the results. Impairments nonspecific to aphasia or either hemisphere . A variety of simple and complex tactual and visual tasks were found not to be associated with aphasia or lesions of right or left hemispheres. These consisted of: measures of time-error for tactual size or weight stimulation, judgment of magnitude of size or weight of objects, discriminations (roughness, pattern, texture, and form), tactual pattern learning, and complex tactual or visual problem solving. Laterality differences . Recent results have shown that the right and left sides of the body surface differ with regard to measures of pressure sensitivity. These results are related both to the individuals familial history of handedness and his own hand preference. Research on impairments concomitant with and spared in aphasia is urged to increase our understanding of this complex neurological disorder.

An attempt to replicate a study of disarranged eye-hand coordination

Three groups of 15 Ss each were tested for disarranged eye-hand coordination in the distance dimension. All groups were tested using a bipartite box which permitted lighting only the upper or lower chambers. S was required to place a dot at the location of a virtual image of a target without seeing his hand. After making 30 such dots he was exposed to one of three conditions, after which he repeated the pre-exposure test. The three conditions were: (a) constrained self-produced hand movement with 7.6 cm. displacement, (b) free hand movement with 7.6 cm. displacement, (c) free hand movement without displacement (control). The results indicated a predominant proportion of individuals with negative adaptation in all groups. The two groups with reafference (stimulation through self-induced movement) and displacement did not differ significantly from the control group in the magnitude or the direction of adaptation. Our results could not be predicted from reafference theory and do not conform to the results of Held and Schlank, in which positive adaptation was obtained in a similar mirror-displacing situation.

THE BENDER-GESTALT TEST IN DIFFERENTIAL DIAGNOSIS OF TEMPORAL LOBECTOMY AND SCHIZOPHRENIA.

Twelve epileptic patients with uncontrolled seizures copied Bender-Gestalt (B-G) drawings before and after unilateral temporal lobectomy, as did 12 hospitalized schizophrenics, individually matched to these patients for age, sex and IQ. Twenty clinical psychologists attempted to differentiate 12 pairs of drawings within one of three sets: (a) pre- vs postoperative, (b) preoperative vs schizophrenic, or (c) postoperative vs schizophrenic. Each judgment was accompanied by a certainty rating. None of the judges exceeded chance expectations; the mean correct performance, 65.4%, exceeded chance expectations. There was also no consistent relationship between the certainty ratings and accuracy of judgment. Twenty laymen with no training in psychology correctly differentiated 62.5% of the postoperative from the schizophrenic drawings. This figure exceeded chance expectations and did not differ significantly from that earned by the psychologists. The Pascal-Suttell objective scoring method demonstrated no relationship between scores and seizure frequency and no predictable change after lobectomy. The authors recommend deletion of B-G, whether clinically judged or objectively scored, from the clinicians armanentarium, at least with regard to differential diagnosis of epilepsy or brain damage from schizophrenia.

DIFFERENTIATION OF HUMAN FIGURE DRAWINGS MADE BEFORE AND AFTER TEMPORAL LOBECTOMY AND BY SCHIZOPHRENICS

Twenty-one clinical psychologists with from 1 to 25 years of experience judged figure drawings made by epileptics before and after temporal lobectomy and by hospitalized schizophrenics. There was no significant ability to differentiate the pre- from the postoperative drawings, or the schizophrenic from either the pre- or postoperative drawings. There was no significant relationship between the ability to differentiate the drawings and years of experience, nor between this ability and certainty of judgment