ABSTRACT
Behavioral evidence concerning memory in forms of high-functioning autism (HFA) and in moderately low-functioning autism (M-LFA) is reviewed and compared. Findings on M-LFA are sparse. However, it is provisionally concluded that memory profiles in HFA and M-LFA (relative to ability-matched controls) are similar but that declarative memory impairments are more extensive in M-LFA than in HFA. Specifically, both groups have diminished memory for emotion- or person-related stimuli. Regarding memory for nonsocial stimuli, both groups probably have mental-age-appropriate nondeclarative memory, and within declarative memory, both groups have mental-age-appropriate immediate free recall of within-span or supraspan lists of unrelated items, as well as cued recall and paired associate learning. By contrast, recognition is largely unimpaired in HFA but moderately impaired in M-LFA, and free recall of meaningful or structured stimuli is moderately impaired in HFA but more severely impaired in M-LFA. Theoretical explanations of data on declarative memory in HFA identify problems in the integrative processing, or the consolidation and storage, of complex stimuli or a specific problem of recollection. Proposed neural substrates include the following: disconnectivity of primary sensory and association areas; dysfunctions of medial prefrontal cortex, hippocampus, or posterior parietal lobe; or combinations of these associated with neural disconnectivity. Hypothetically, perirhinal dysfunction might explain the more extensive declarative memory impairments in M-LFA. Foreseeable consequences of uneven memory abilities in HFA and M-LFA are outlined, including possible effects on language and learning in M-LFA. Finally, priorities for future research are identified, highlighting the urgent need for research on memory in lower functioning individuals.
Subject(s)
Autistic Disorder/physiopathology , Memory Disorders/physiopathology , Memory/physiology , Autistic Disorder/pathology , Autistic Disorder/psychology , Emotions , Face , Hippocampus/pathology , Hippocampus/physiopathology , Humans , Memory Disorders/pathology , Neuropsychological Tests , Parietal Lobe/pathology , Parietal Lobe/physiopathology , Prefrontal Cortex/pathology , Prefrontal Cortex/physiopathology , Research Design , Severity of Illness IndexABSTRACT
We hypothesise that of the two processes underlying declarative memory, recollection is impaired in high-functioning autism (HFA) whereas recollection and familiarity are impaired in low-functioning autism (LFA). Testing these hypotheses necessitates assessing recollection and familiarity separately. However, this is difficult, because both processes contribute to performance on standard memory tests. Moreover, tests must be suitable for use with young or intellectually disabled participants. This study aimed to develop tests of recollection and familiarity separately, and to make preliminary tests of our hypotheses. We developed a temporal source memory task to assess recollection in LFA, and a shape recognition task to assess familiarity and an action recall task assessing recollection in HFA. The methods and implications of the results are discussed.
Subject(s)
Child Development Disorders, Pervasive/physiopathology , Mental Recall , Neuropsychological Tests , Recognition, Psychology , Adolescent , Child , Female , Humans , Intelligence Tests , MaleABSTRACT
Lack of pretense in children with autism has been explained by a number of theoretical explanations, including impaired mentalising, impaired response inhibition, and weak central coherence. This study aimed to empirically test each of these theories. Children with autism (n = 60) were significantly impaired relative to controls (n = 65) when interpreting pretense, thereby supporting a competence deficit hypothesis. They also showed impaired mentalising and response inhibition, but superior local processing indicating weak central coherence. Regression analyses revealed that mentalising significantly and independently predicted pretense. The results are interpreted as supporting the impaired mentalising theory and evidence against competing theories invoking impaired response inhibition or a local processing bias. The results of this study have important implications for treatment and intervention.
Subject(s)
Autistic Disorder/psychology , Cognition Disorders/diagnosis , Culture , Fantasy , Intellectual Disability/psychology , Autistic Disorder/epidemiology , Child, Preschool , Cognition Disorders/epidemiology , Female , Humans , Intellectual Disability/diagnosis , Intellectual Disability/epidemiology , Male , Neuropsychological Tests , Play and Playthings , Severity of Illness IndexABSTRACT
The hypothesis that a pervasive impairment of declarative memory contributes to language impairment in low functioning autism (LFA) was tested. Participants with LFA, high functioning autism (HFA), intellectual disability (ID) without autism, and typical development (TD) were given two recognition tests and four tests of lexical understanding. It was predicted that recognition would be impaired in the LFA group relative to the HFA and TD groups but not the ID group, and that recognition would correlate with lexical knowledge in the LFA group but none of the other groups. These predictions were supported except that the HFA group performed more similarly to the LFA group than expected, a finding interpreted in terms of selectively impaired episodic memory.
