Biomedical subjects

L E Cutting

Publications and source records attributed to L E Cutting.

10 recordsLinked to original sources

PubMed2006

Sex differences in cerebral laterality of language and visuospatial processing.

Sex differences on language and visuospatial tasks are of great interest, with differences in hemispheric laterality hypothesized to exist between males and females. Some functional imaging studies examining sex differences have shown that males are more left lateralized on language tasks and females are more right lateralized on visuospatial tasks; however, findings are inconsistent. Here we used functional magnetic resonance imaging to study thirty participants, matched on task performance, during phonological and visuospatial tasks. For each task, region-of-interest analyses were used to test differences in cerebral laterality. Results indicate that lateralization differences exist, with males more left lateralized during the phonological task and showing greater bilateral activity during the visuospatial task, whereas females showed greater bilateral activity during the phonological task and were more right lateralized during the visuospatial task. Our data provide clear evidence for differences in laterality between males and females when processing language versus visuospatial information.

Adult↗

PubMed2005

Differential components of sentence comprehension: beyond single word reading and memory.

A number of studies have used functional neuroimaging to examine the neural mechanisms of sentence comprehension; however, few fMRI studies have examined activation patterns associated with sentence comprehension after accounting for activation attributable to single-word-level tasks important for sentence comprehension. To investigate the patterns of activation associated with sentence comprehension after controlling for single word reading and maintaining single words in memory, 20 unimpaired adult readers completed a block design paradigm which included sentence comprehension, single word reading, and short-term memory (for words) tasks. Results indicated that, regardless of the aspect of sentence comprehension being controlled for, activation was observed in bilateral temporal lobes (left > right) as well as bilateral occipital lobes and middle frontal gyri. Additional findings showed that bilateral superior parietal lobe activation was greatest for short-term memory for words, while left anterior inferior frontal gyri activation (centered around Brodmann's area 47) was greatest for single word reading. Results suggest that temporal cortex (left > right) is a core region important for sentence comprehension beyond the short-term memory and semantic requirements inherent in processing sentences.

Adult↗

PubMed2005

Subtle executive impairment in children with autism and children with ADHD.

BACKGROUND: The executive functions of inhibition, planning, flexible shifting of actions, and working memory are commonly reported to be impaired in neurodevelopmental disorders. METHOD: We compared these abilities in children (8-12 years) with high functioning autism (HFA, n = 17), attention deficit-hyperactivity disorder (ADHD, n = 21) and healthy controls (n = 32). Response inhibition was assessed using the Stroop Color and Word Test (Golden, 1978). Problem solving, set-shifting, and nonverbal memory were assessed using three tasks, respectively, from the CANTAB (Cambridge Cognition, 1996): the Stockings of Cambridge task; the Intra-Dimensional/Extra-Dimensional set-shifting task; and the Spatial Working Memory task (SWM) with tokens hidden behind 3, 4, 6, and 8 boxes. RESULTS: There were no group differences on the response inhibition, planning, or set-shifting tasks. On the SWM task, children with HFA made significantly more between-search errors compared with controls on both the most difficult problems (8-box) and on the mid-difficulty problems (6-box); however, children with ADHD made significantly more errors compared to controls on the most difficult (8-box) problems only. CONCLUSION: Our findings suggest that spatial working memory is impaired in both ADHD and HFA, and more severely in the latter. More detailed investigation is needed to examine the mechanisms that differentially impair spatial working memory, but on this set of tasks there appears to be sparing of other executive functions in these neuropsychiatric developmental disorders.

Attention Deficit Disorder with Hyperactivity↗

PubMed2002

Megalencephaly in NF1: predominantly white matter contribution and mitigation by ADHD.

BACKGROUND: Megalencephaly is a frequent CNS manifestation in neurofibromatosis type 1 (NF1); however, its tissue composition, modification by attention deficit hyperactivity disorder (ADHD), and relationship with unidentified bright objects (UBO) remain controversial. METHODS: Eighteen male patients with NF1, seven of whom had ADHD (NF1+ADHD), were compared with 18 age- and sex-matched controls in terms of MRI-, Talairach-based brain, cerebral, lobar, and sublobar gray and white matter volumes. Twelve subjects with NF1 had UBO in the centrencephalic region, whereas six had no UBO or exclusively infratentorial lesions. RESULTS: Patients with NF1 without ADHD (NF1-pure) had the largest total cerebral, gray, and white matter volumes with larger parietal/somatosensory white matter volumes than controls, particularly if UBO were present in the basal ganglia. All subjects with NF1 (including NF1+ADHD) had larger total and frontal white matter volumes than controls. Smaller frontal/right prefrontal gray matter volumes were found in NF1+ADHD when compared with NF1-pure patients. CONCLUSIONS: The increase in frontal and parietal white matter volumes in male patients with NF1, including the preferential centrencephalic distribution, supports the hypothesis that NF1's white matter pathology encompasses but is not limited to visible UBO. Male patients with NF1+ADHD, as compared with NF1-pure patients, showed frontal reductions that are largely consistent with those found in idiopathic ADHD.

Adolescent↗

PubMed2002

Disproportionate increases of white matter in right frontal lobe in Tourette syndrome.

OBJECTIVE: Based on previous findings implicating abnormalities of cortico-striatal-thalamo-cortical circuitry in Tourette syndrome (TS), the authors performed a volumetric analysis of frontal and nonfrontal tissue (gray + white matter) in boys with TS, with and without attention deficit hyperactivity disorder (ADHD). METHODS: Frontal and nonfrontal gray and white matter compartment volumes, obtained by a MRI protocol, were analyzed with a 2 x 2 factorial multivariate analysis of variance approach for associations with a TS or ADHD factor in 11 boys with TS only, 14 with TS + ADHD, 12 with ADHD only, and 26 healthy boys. RESULTS: In subjects with TS, the right frontal lobe showed a larger proportion of white matter. In addition, results were consistent with previous reports of reduced frontal lobe volumes associated with ADHD. Our analyses suggested these reductions to be mainly the consequence of smaller gray matter volumes, particularly on the left. CONCLUSIONS: These findings, suggesting the volumetric composition of frontal lobe tissue to be different in TS, support the hypothesis proposing frontostriatal pathway involvement in the pathophysiology of the disorder. Differences in composition of right frontal lobe attributable to white matter do not definitively implicate the hypothesized fiber pathways; however, considered in the context of the unilateral directionality of frontal-striatal circuitry, these results suggest the white matter connections as one explanation for basal ganglia anomalies (loss of normal left > right asymmetry) in TS.

Adolescent↗

PubMed2001

Oculomotor abnormalities in attention deficit hyperactivity disorder: a preliminary study.

BACKGROUND: Prevailing hypotheses suggest that attention deficit hyperactivity disorder (ADHD) is secondary to dysfunction of motor intentional systems mediated by prefrontal circuitry. Oculomotor paradigms provide a mechanism for examining and localizing dysfunction at the interface between movement and cognition. OBJECTIVE: Three different saccade tasks (reflexive or prosaccades, antisaccades, and memory-guided saccades) were used to examine functions necessary for the planning and the execution of eye movements, including motor response preparation, response inhibition, and working memory. METHODS: The study included 19 children with ADHD, divided into two groups: a group of 8 children on methylphenidate at the time of testing and a group of 11 children not taking any psychoactive medication. Results from the two groups were compared with those from 25 age- and gender-matched normal control children. RESULTS: Both groups of children with ADHD made significantly more directional errors than did controls on the antisaccade task and significantly more anticipatory errors than did controls on the memory-guided saccade task, findings that are consistent with deficits in response inhibition. There were no significant differences in prosaccade latency, although unmedicated children with ADHD showed significantly greater variability in latency on the prosaccade task than did controls. On the memory-guided saccade task there were no significant differences in saccade accuracy; however, unmedicated children with ADHD showed longer saccade latency than did either controls or medicated children with ADHD. CONCLUSIONS: Oculomotor findings suggest that deficits in prefrontal functions, in particular response inhibition, contribute to behavioral abnormalities observed in ADHD. Findings also suggest that the administration of methylphenidate is associated with improvements in the consistency of motor response. Although there were no observed improvements in response inhibition with methylphenidate, conclusions await a design in which subjects complete testing both on and off medication.

Adolescent↗

PubMed2000

The association of neurofibromatosis type 1 and attention deficit hyperactivity disorder.

Some research and clinical observations have linked Neurofibromatosis Type 1 (NF-1) and Attention Deficit Hyperactivity Disorder (ADHD). In order to investigate whether ADHD is part of the phenotype of NF-1 or is a separate, unrelated disorder within families, we compared the ADHD status of children affected with NF-1 to that of their unaffected-NF-1 siblings and to that of their biological parents. Results of matched-pair analyses were calculated and revealed a significant with-in pair discordance, when comparing children with NF-1 and their siblings and when comparing children with NF-1 and their biological parents (in families with a sporadic, non-familial NF-1 child). These findings suggest that ADHD may occur as a component of the NF-1 phenotype.

Adolescent↗

PubMed2000

Relationship of cognitive functioning, whole brain volumes, and T2-weighted hyperintensities in neurofibromatosis-1.

Using quantitative magnetic resonance imaging morphometry, we report that the whole brain volumes of patients with neurofibromatosis-1 are significantly larger than normal, confirm the prevalence of macrocephaly as about 50%, and report that macrocephaly in patients with neurofibromatosis-1 does not appear to be related to the familial or sporadic origin of the neurofibromatosis-1 or to the presence or absence of T2-weighted hyperintensities. No strong relationship emerged between the extent of neurofibromatosis-1-associated impairment of cognitive functions and degree of macrocephaly; however, the macrocephalic neurofibromatosis-1 group did have a significant verbal impairment relative to the nonmacrocephalic neurofibromatosis-1 group in vocabulary (P < .009).

Adolescent↗

PubMed2000

How children with neurofibromatosis type 1 differ from "typical" learning disabled clinic attenders: nonverbal learning disabilities revisited.

To further investigate cognitive deficits in children with Neurofibromatosis Type 1 (NF-1), children with NF-1 were compared to typical learning disabled clinic attenders (LD-clinic), all of whom had reading disabilities, as well as to a group with no disabilities (NoDx). Results indicated that both the NF-1 group and LD-clinic group had reading and reading-related deficits when compared to the NoDx group; however, the NF-1 group was more globally language impaired than the LD-clinic group. In addition, the NF-1 group scored significantly lower than the LD-clinic group, but not the NoDx group, on the visuospatial measures, thus confirming that children with NF-1 have visuospatial deficits not typical of a general LD-clinic population. The NF-1 group was not impaired in comparison to the NoDx group on certain language and visuospatial tasks that were previously found to be deficits in sibling pairwise matched designs; thus, the importance of considering genetic and familial context when studying the impact of genetic disorders on cognition was demonstrated.

Attention Deficit Disorder with Hyperactivity↗

PubMed2000

Judgment of duration in individuals with ataxia-telangiectasia.

Several clinical investigations with adults suggest that the cerebellum may be critical for judgment of explicit time intervals; however, little work has been done in populations with lesions of the cerebellum acquired during development. We evaluated 17 individuals with ataxia-telangiectasia (AT), an autosomal recessive disorder with on-set in early childhood characterized by diffuse, almost selective, degeneration of the cerebellar cortex, and 21 normal controls, matched for age. Because patients with AT have motor impairment, verbal IQ (VIQ) was used to estimate intelligence; VIQ was significantly lower in the group with AT (p < .0001). Participants were tested using a test of judgment of duration that has been found to be impaired in adults with cerebellar lesions and a contrasting auditory control task (not impaired in adults with cerebellar lesions) involving judgment of pitch. After statistically controlling for VIQ, the 2 groups did not differ significantly on judgment of pitch, but those with AT performed significantly worse than controls on judgment of duration (p = .01). Children and adolescents with AT show deficits in judgment of duration but not of pitch, suggesting that the cerebellum may be critical for judgment of explicit time intervals at all ages.

Adolescent↗