Cerebellar-induced apraxic agraphia: a review and three new cases

Apraxic agraphia is a writing disorder due to a loss or lack of access to motor engrams that program the movements necessary to produce letters. Clinical and functional neuroimaging studies have demonstrated that the neural network responsible for writing includes the superior parietal region and the dorsolateral and medial premotor cortex. Recent studies of two cases with atypical lesion localisations in the left thalamus and the right cerebellum support the hypothesis that the written language network is larger than previously assumed. The aim of this study is twofold: (1) to provide a survey of cases of apraxic agraphia published between 1973 and June 2010, and (2) to provide further evidence for a role of the cerebellum in writing via three additional cases who presented with apraxic agraphia after ischemic damage in the cerebellum. Functional neuroimaging studies by means of brain perfusion SPECT showed perfusional deficits in the anatomoclinically suspected supratentorial areas, subserving language dynamics, syntax, naming, writing and executive functioning.     

Infantile amnesia reconsidered: a cross-cultural analysis

A number of theories have been offered over the past hundred years to explain the phenomenon of infantile amnesia, the common inability to remember autobiographical experiences from the first years of life. Recent comparative studies that examine autobiographical memories in different populations, particularly populations in North America and East Asia, have yielded intriguing findings that provide a unique opportunity to revisit some of the major theoretical views and to propose new accounts. In light of these findings, this article discusses five theoretical explanations for infantile amnesia, including cognitive and social discontinuity, the emergence of the self, early parent-child memory sharing, functions of autobiographical memory, and the complexity of life experience. The reconsideration of infantile amnesia from a cross-cultural perspective suggests that while the basic mechanisms and contributing factors may be universal, the specific ways in which these mechanisms and factors are manifested differ qualitatively across cultures. A theoretical approach that takes the larger cultural context into account can help us understand this long-standing puzzle.     

Functional amnesia: clinical description and neuropsychological profile of 10 cases

We carried out the first neuropsychological study of a series of patients with functional amnesia. We evaluated 10 patients, first with a neurological examination and then with three tests of anterograde amnesia and four tests of retrograde amnesia. Excluding one patient who later admitted to malingering, all patients had a significant premorbid psychiatric history and one or more possible precipitating factors for their amnesia. Eight of the 10 patients still had persistent retrograde amnesia at our last contact with them (median = 14 mo after the onset of amnesia). On tests of anterograde amnesia, the patients performed normally as a group, though some patients scored poorly on tests of verbal memory. On tests of retrograde amnesia, all patients had difficulty re-collecting well-formed autobiographical memories of specific events from their past. In contrast, patients performed as well as controls at distinguishing the names of cities from fictitious city names. On remote memory tests for past public events and famous faces, different patients exhibited different but internally consistent patterns of impaired and spared performance. The variability in the clinical and neuropsychological findings among our patients may be understood by supposing that memory performance is poor in proportion to how directly a test appears to assess a patient's common sense concept of memory. The presentation of patients with functional amnesia is as variable as humankind's concept of what memory is and how it works.     

Impaired priming of new associations in amnesia

We assessed priming of new associations in amnesic patients and healthy control subjects in a paradigm developed by Graf and Schacter (1985). Subjects were presented unrelated word pairs embedded in sentences (e.g., A BELL was hanging over the baby's CRADLE) and were asked to rate how well the sentences related the two words. Subjects were then given a word completion test. They were shown three-letter word stems and were asked to complete the stem with the first word that came to mind. In the same context condition, each word stem was presented together with the word that had appeared in the same sentence during study (e.g., BELL-CRA--). In the different context condition, each stem was presented together with a new word that had never been presented (e.g., APPLE-CRA--). Control subjects completed more words in the same context condition than in the different context condition. In contrast, amnesic patients did not complete any more words in the same context condition than in the different context condition. Indeed, across two experiments none of the amnesic patients exhibited consistent priming of new associations. Thus, although amnesic patients do exhibit entirely normal priming of preexisting memory representations, they do not appear to exhibit priming of new associations in this paradigm.     

Current scientific interest in dissociative amnesia: A bibliometric analysis

In a bibliometric analysis, we used the PubMed search engine to count the number of publications identified by the search term “dissociative amnesia” for the years 2011–2020. We then counted publications from the same decade for five representative comparison disorders: “panic disorder,” “anorexia nervosa,” “obsessive–compulsive disorder,” “attention deficit hyperactivity disorder,” and “bipolar disorder.” Our search yielded only 89 publications for “dissociative amnesia,” and only seven of these involved localized or selective amnesia for specific events. By contrast, we found between 3000 and 21,000 publications for each of the five comparison disorders during 2011–2020. We performed several additional secondary analyses, all of which suggested that the diagnosis of “localized or selective dissociative amnesia” has generated little scientific interest in recent years. Examining possible hypotheses to explain this lack of interest, it appears most likely that the concept of localized or selective dissociative amnesia is not widely accepted among scientists at present.     

The fractionation of retrograde amnesia

This single case study describes our investigations of the retrograde memory deficit of a patient who became severely and selectively amnesic after an encephalitic illness. On clinical assessment his retrograde deficit for both personal and public events appeared to encompass his entire adult life. However, he retained knowledge of words introduced into the vocabulary during the retrograde period. The experimental investigation documented his inability to recall, recognize, and place in temporal order the names and faces of famous people for all time periods sampled. By contrast, his recall of either a famous face or a famous name was significantly facilitated by the verbal cue of the person's first name and initial of the surname (i.e., Margaret T...). His performance on a test of "familiarity" that required him to select the famous name or the famous face from two distractors (unknown) was within normal limits. It is argued that names and faces of famous people are represented in more than one system: both in a vocabulary-like fact memory system that is preserved and also in a congnitively mediated schemata that in this case is functionally inoperative.     

The many faces of amnesia

Results from studies of retrograde amnesia provide much of the evidence for theories of memory consolidation. Retrograde amnesia gradients are often interpreted as revealing the time needed for the formation of long-term memories. The rapid forgetting observed after many amnestic treatments, including protein synthesis inhibitors, and the parallel decay seen in long-term potentiation experiments are presumed to reveal the duration of short-term memory processing. However, there is clear and consistent evidence that the time courses obtained in these amnesia experiments are highly variable within and across experiments and treatments. The evidence is inconsistent with identification of basic temporal properties of memory consolidation. Alternative views include modulation of memory and emphasize the roles that hormones and neurotransmitters have in regulating memory formation. Of related interest, converging lines of evidence suggest that inhibitors of protein synthesis and of other biochemical processes act on modulators of memory formation rather than on mechanisms of memory formation. Based on these findings, memory consolidation and reconsolidation studies might better be identified as memory modulation and "remodulation" studies. Beyond a missing and perhaps unattainable time constant of memory consolidation, some current views of memory consolidation assume that memories, once formed, are generally unmodifiable. It is this perspective that appears to have led to the recent interest in memory reconsolidation. But the view adopted here is that memories are continually malleable, being updated by new experiences and, at the same time, altering the memories of later experiences. Studies of memory remodulation offer promise of understanding the neurobiological bases by which new memories are altered by prior experiences and by which old memories are altered by new experiences.     

Towards a new functional anatomy of language

The classical brain-language model derived from the work of Broca, Wernicke, Lichtheim, Geschwind, and others has been useful as a heuristic model that stimulates research and as a clinical model that guides diagnosis. However, it is now uncontroversial that the classical model is (i) empirically wrong in that it cannot account for the range of aphasic syndromes, (ii) linguistically underspecified to an extent that prohibits contact with the language sciences, and (iii) anatomically underspecified. We briefly summarize some of the central issues that motivate why a new functional anatomy of language is necessary, in the context of introducing a collection of articles that describe systematic new attempts at specifying the new functional anatomy. The major convergent observations are highlighted and the emergent conceptual and empirical trends are identified.     

Psychology and the politics of same-sex desire in the United States: an analysis of three cases

Psychological science has assumed an increasingly explicit role in public policies related to same-sex desire in the United States. In this article, we present a historical analysis of the relationship between policy discourse and scientific discourse on homosexuality produced within U.S. psychology over the 20th and early 21st centuries through the lens of three cases: Bowers v. Hardwick (1986), Lawrence v. Texas (2003), and Perry v. Schwarzenegger (2010). Our analysis suggests that, for the majority of its disciplinary history, psychology produced knowledge that supported a status quo of legal and cultural subordination for same-sex-attracted individuals. The discipline's shift in understanding of homosexuality, reflected in a 1975 policy statement of the American Psychological Association, reversed this relationship and opened up space for advocacy for social and political change regarding homosexuality. Our analysis of policy decisions rendered by the courts reveals the increasingly important role psychological science has assumed in challenging the legal subordination of same-sex-attracted individuals, though the basis upon which psychological science has sought to inform policy remains limited. We conclude with a critical discussion of the type of knowledge claims psychologists have traditionally used to advocate for gay and lesbian rights, suggesting the vitality of a narrative approach which can reveal the meaning individuals make of legal subordination and political exclusion.     

Introducing philosophy of medicine: three new books

Theoretical Medicine and Bioethics -     

THOG: The anatomy of a problem

Summary Three experiments are reported on the attempts to solve a novel hypothetico-deductive problem. Its solution demands both the postulation of hypotheses about its structure and a combinatorial analysis upon the consequences of these hypotheses. The majority of subjects (students) failed to solve the problem because they argued from the properties of stimuli rather than from hypotheses about their conceptual status. The results suggest that a familiarity with the logical structure of the problem and the elicitation of appropriate hypotheses failed to correct this intuitive approach. These findings are discussed in relation to Piaget's theory of formal operations, and (very tentatively) in relation to habitual styles of thought.     

The effects of repeating a recognition test in lorazepam-induced amnesia: Evidence for impaired contextual memory as a cause of amnesia

In two experiments, a recognition test for an earlier presented list was given twice in immediate succession (Test 1 and Test 2). On the hypothesis that anterograde amnesia for episodic memory involves a deficit in contextual memory, amnesic subjects should confuse familiarity with distractor items gained during Test 1 with familiarity gained during original list presentation. As a result, they should think that they recognize more items on Test 2. This will lower recognition efficiency in Test 2 by increasing false alarms rather than by reducing hits. For subjects with an amnesia induced by lorazepam, but not for control subjects, recognition efficiency was substantially reduced in Test 2 in both experiments. As predicted, this impairment was due to a large increase in false alarms, with no decrease in the number of hits. The impairment could not be explained by a difference in recognition level between lorazepam and control subjects on Test 1. These findings therefore support the contextual memory deficit hypothesis of anterograde amnesia. Their implications for understanding the relationship between recall and recognition in amnesia are discussed.     

Phoneme errors in Broca's aphasia: three Finnish cases

The phonemic errors of three Finnish Broca's aphasics were analyzed according to various phonological features, frequency of segments, syllable, word, and stress positions, as well as for the phonotactic structure of the uncanonical products. It was found, e.g., that the distance between the syntagmatic error and its source could not be satisfactorily counted by phonemes, since the syllable had to be taken into account also in pathological Finnish. As regards the paradigmatic dimension of the errors, the number of incorrect features is even here in reverse relation to the frequency of the erroneous phonemes. Moreover, it was found that pure quantity errors and vowel harmony deviations are infrequent in the speech of Finnish Broca's aphasics.     

Clinicopathological findings of suicide in the elderly: three cases

The neuropathological correlates of suicide in older persons have received little research attention. Our recent study of elderly suicide victims from an Australian forensic medicine department (n = 143), unlike a previous case-control study, did not find an increased prevalence of Alzheimer's disease (AD) in older persons who committed suicide despite a history of dementia in 6.3%. Both studies were limited to the examination of AD-related pathology by the availability of tissue. We present clinicopathological data on three cases from our study for whom autopsy findings were available. These cases included: a community-dwelling male in his early eighties with dementia who was found to have multiple cortical and striatal lacunes and glial scars, small vessel cerebrovascular disease (SVD) and AD-related pathology; a community-dwelling male in his mid-seventies with depression and loss of concentration, with brainstem predominant Lewy body disease (LBD) and AD-related pathology; and a female nursing home resident in her nineties with a history of stroke and prior suicide attempts who was found to have infarcts and SVD in frontal regions. Neuropathological findings in elderly suicide victims may include multiple neurodegenerative pathologies. The burden and distribution of neurodegenerative diseases apart from AD, including SVD and LBD, should be assessed as possible pathophysiological factors contributing to late life suicide.     

Forensic hypnosis to lift amnesia: The jury is still out

In recent years, there has been a sharp increase in the use of forensic hypnosis to lift amnesia in victims and witnesses who may have repressed or otherwise forgotten evidentiary details. This paper addresses the reliability of memories that result from forensic hypnosis, as well as the impact that hypnotically refreshed testimony has on a jury. Because of the mixed data on the reliability of hypnotically enhanced memories, the increasing use of this forensic tool on amnesics is questioned.     

The causes and consequences of transient epileptic amnesia

Transient epileptic amnesia (TEA) is a recently recognised syndrome of epilepsy in which the principle manifestation of seizures is recurrent episodes of isolated memory loss. In this article, we describe the clinical and cognitive profile of this emerging syndrome, and present new data that provide at most weak support for its proposed relationship to cerebrovascular disease. TEA is often associated with two unusual forms of interictal memory impairment: accelerated long-term forgetting and remote memory impairment. We discuss the clinical and theoretical implications of these relatively novel cognitive deficits.     

The anatomy of loneliness

Loneliness is a potent but little understood risk factor for broad-based morbidity and mortality. We review five social neurobehavioral mechanisms that may account for this association. The evidence suggests that different mechanisms explain short-term and long-term effects, and that the long-term effects operate through multiple pathways. Implications for the design of interventions are discussed.