Felicia C. Goldstein

Organization of verbal memory after severe closed-head injury.

Verbal learning and memory over repeated trials were studied in 12 severely closed-head-injured patients and a matched control group of 10 subjects for three types of word lists, i.e., unrelated, related but unclustered, and clustered words. Verbal memory was facilitated in both groups by presentation of related words in a clustered format. However, the performance of head-injured patients was characterized by low levels of recall, clustering, and subjective organization. In addition, they had a larger number of intrusive errors. The results provide evidence for some preserved semantic memory following closed-head injury and their implications for rehabilitation are discussed.

Memory functioning during the first year after closed head injury in children and adolescents

Effects of the severity of closed head injury (CHI) on verbal learning and memory and visual recognition memory were studied at base line and on a 1-year follow-up examination in 58 pediatric admissions sampled from three age ranges, 6-8, 9-12, and 13-15 years. Within each age range, recovery of memory was compared in patients with mild to moderate CHI and survivors of severe injury. Consistent with previous findings obtained in head-injured children sampled from a wide age range, the present study confirms that memory deficit persists at least 1 year after severe CHI. Impairment of visual recognition memory was directly related to severity of CHI in all three age ranges. The severity of CHI was directly related to initial and residual verbal memory deficit in adolescents, but this effect was inconsistent in children. We suggest that the cerebral substrate for visual recognition memory was well established in all three age ranges and thus was vulnerable to the effects of injury. In contrast, verbal memory skills were undergoing rapid development in the adolescents, but were still immature in children. Extended follow-up could conceivably demonstrate the late appearance of verbal memory deficit in the children who had apparent sparing of function.

Epidemiology of Pediatric Closed Head Injury Incidence, Clinical Characteristics, and Risk Factors

This paper reviews the epidemiology of pediatric closed head injury. Incidence rates, etiologic/pathophysiologic correlates, and associated risk factors are discussed. Future research directions include the need to consider the relationships among age, etiology, and pathophysiology in outcome studies as well as inclusion of premorbid measures of personality/intellectual functioning.

Automatic and effortful processing after severe closed head injury.

To investigate the automatic versus effortful distinction following severe closed head injury (CHI), we administered free recall and frequency of occurrence tasks to patients and controls. In Experiment 1 we found that both free recall (an effortful task) and judgment of relative frequency of occurrence (an automatic task) were impaired in 15 CHI patients as compared to 14 controls. In Experiment 2 we corroborated this finding and showed that absolute estimates of frequency were also impaired in new samples of 16 patients and 16 controls. We infer that cognitive tasks which normal individuals can perform without practice, feedback, or instructions may demand more effortful strategies following severe CHI.

Intellectual and academic outcome following closed head injury in children and adolescents: Research strategies and empirical findings

The literature on intellectual and academic outcome after closed head injury in children and adolescents is reviewed. The research strategies and variables used to evaluate recovery are considered in terms of empirical findings and methodological issues. It is argued that assessment of outcome must take place within the context of an understanding of the childs premorbid behavioral and cognitive functioning. In addition, more fine‐grained tests of cognition other than global IQ measures should be utilized to tap subtle information processing, problem solving, and scholastic achievement deficits resulting from traumatic brain injury.

Assessment of the accuracy of regression equations proposed for estimating premorbid intellectual functioning on the Wechsler Adult Intelligence Scale.

This investigation examined the accuracy of regression equations proposed by Wilson et al. (1978) for estimating premorbid intellectual quotients (IQs) on the Wechsler Adult Intelligence Scale (WAIS). Actual Verbal, Performance, and Full Scale IQs in a sample of 69 neurologically normal adults were compared against their estimated premorbid levels. While the equations provided an adequate overall fit to the data, actual IQ values at the extremes of the WAIS Scales were found to be most susceptible to underestimation (high actual IQ values) or overestimation (low actual IQ values). The clinical importance of this finding and possible applications of the equations are discussed.

Hemispheric Disconnection Syndrome Persisting after Anterior Cerebral Artery Aneurysm Rupture

Hemispheric disconnection syndrome is a rarely reported sequela of aneurysm rupture. Serial neurobehavioral examinations of such a patient after clipping of a right pericallosal artery that had bled into a large portion of the corpus callosum disclosed defects in interhemispheric transfer of information and competitive movements between the left and right extremities. Although the patients postoperative memory deficit subsequently resolved, his disconnection syndrome persisted and was primarily responsible for his disability despite otherwise normal neurological findings. We studied a second patient with a hematoma in the genu of the corpus callosum secondary to an arteriovenous malformation (AVM). Although the second patient also exhibited postoperative memory problems, her hemispheric disconnection symptoms were minimal and commensurate with a more circumscribed corpus callosum lesion. Neurobehavioral sequelae of aneurysm or AVM rupture involving the anterior circulation, which may be overlooked in the absence of a detailed examination, can produce persistent disability in many patients.

Automatic Processing of Frequency Information in Survivors of Severe Closed Head Injury

Several information processing theories have proposed that individuals possess limited capacity for engaging in activities and that performance on various tasks depends, in part, upon the quantity and type of resources required (Hasher & Zacks, 1979; Kahneman, 1973; Navon & Gopher, 1979; Posner & Snyder, 1975; Shiffrin & Schneider, 1977). The notion of capacity refers to the basic amount of information that can be stored, transmitted, and processed. Individual difference variables such as age or intelligence have been posited to affect the amount of basic processing resources available for efficient performance. With increasing age, for example, less capacity may be available for performance on memory tasks that ordinarily place a heavy load on this limited pool. On the other hand, task variables such as difficulty or prior experience can also determine the ease of processing. Tasks that are relatively unfamiliar may require more resources than others.

Multiple resources: the concepts of task difficulty and response requirements

The variables of task difficulty and response requirements were examined within the multiple resources framework. The performance of 54 undergraduates was monitored on a visual target detection task as the difficulty of auditory shadowing was manipulated. Response competition was examined by varying the time at which subjects responded to the visual target. In line with multiple resources theory, there were no significant differences in target detection as a function of different demands of auditory shadowing, and there was no evidence for switching between auditory and visual inputs. Subjects were devoting their effort toward shadowing as measured by control trials of shadowing alone. Although evidence for response competition was not obtained in the hypothesized direction, the subjects who responded to visual targets while continuing to shadow performed better than other subjects. Alternative theories and the notion that effort may refer to the range of available processing strategies are discussed.