Journal Articles
This page lists current research articles in the field of learning disabilites.
BACKGROUND:
Previous studies have found that child attention-deficit/hyperactivity disorder (ADHD) is associated with more parental marital problems. However, the reasons for this association are unclear. The association might be due to genetic or environmental confounds that contribute to both marital problems and ADHD.
METHOD:
Data were drawn from the Australian Twin Registry, including 1,296 individual twins, their spouses, and offspring. We studied adult twins who were discordant for offspring ADHD.Using a discordant twin pairs design, we examined the extent to which genetic and environmental confounds,as well as measured parental and offspring characteristics, explain the ADHD-marital problems association.
RESULTS:
Offspring ADHD predicted parental divorce and marital conflict. The associations were also robust when comparing differentially exposed identical twins to control for unmeasured genetic and environmental factors, when controlling for measured maternal and paternal psychopathology,when restricting the sample based on timing of parental divorce and ADHD onset, and when controlling for other forms of offspring psychopathology. Each of these controls rules out alternative explanations for the association.
CONCLUSION:
The results of the current study converge with those of prior research in suggesting that factors directly associated with offspring ADHD increase parental marital problems.
OBJECTIVE:
To examine the relationship between ADHD medications, study habits, and academic achievement of ADHD-diagnosed undergraduates.
METHOD:
A total of 92 students with a self-reported ADHD diagnosis and a current prescription for ADHD medication were compared with 143 control students in a survey of academic performance.
RESULTS:
Most ADHD students took stimulant medication and said the drugs helped them, yet believed they were worse than other students at planning and completing assignments and avoiding distractions. Although most study habits of ADHD students did not differ from controls, their high school and college GPA (grade point average), and ACT scores were significantly lower, and they withdrew from significantly more classes than did control students. Interestingly, preliminary data suggested that good study habits alone, even without stimulants, could overcome the achievement disparity of ADHD students.
CONCLUSION:
As previously shown for children and adolescents, stimulant medications alone did not eliminate the academic achievement deficit of ADHD undergraduates.
Dr. Levinson's comment:
Believe it or not:The authors state that preliminary data suggests that good study habits alone can overcome the achievement disparity of ADHD students whereas helpful stimulant medications did not. According to Levinson's experience, ADHD is a medical disorder most often complicated by dyslexia or LD. It can be significantly helped by medical and non-medical therapies--but not "cured."
OBJECTIVE:
The existence of neuropsychological deficits has been implicated in obsessive-compulsive disorder (OCD), particularly memory, attention, and executive functions. However, few studies have focused on neuropsychological deficits in the relatives of OCD patients. The aim of this study was to investigate cognitive deficits in OCD patients and their parents.
METHODS:
Forty patients with OCD, 48 parents of these patients, and 87 healthy controls completed a neuropsychological testing battery.
RESULTS:
Both OCD patients and their parents showed impairments in delayed verbal memory and delayed visual memory. Furthermore, they performed worse than healthy controls in problem-solving ability. Dr. Levinson suggests these results support his research indicating a correlation of anxiety disorders with dyslexia and cerebellar-vestibular dysfunction.
CONCLUSION:
Our study demonstrated familial aggregation of delayed memory deficits and impaired problem-solving ability, which may be the potential neuropsychological endophenotypes of hereditary susceptibility to OCD.
OBJECTIVE:
The authors examined the specificity and course of psychiatric disorders from early childhood through adolescence in offspring of parents with confirmed panic disorder and major depressive disorder.
METHOD:
The authors examined rates of psychiatric disorders at 10-year-follow-up (mean age, 14 years) in four groups: offspring of referred parents with panic and depression (N=137), offspring of referred parents with panic without depression (N=26), offspring of referred parents with depression without panic (N=48), and offspring of nonreferred parents with neither disorder (N=80). Follow-up assessments relied on structured interviews with the adolescents and their mothers; diagnoses were rated present if endorsed by either.
RESULTS:
Parental panic disorder, independently of parental depression, predicted lifetime rates in offspring of multiple anxiety disorders, panic disorder, agoraphobia, social phobia, and obsessive-compulsive disorder. Parental depression independently predicted offspring bipolar, drug use, and disruptive behavior disorders. Parental panic and depression interacted to predict specific phobia and major depressive disorder. Phobias were elevated in all at-risk groups, and depression was elevated in both offspring groups of parents with depression (with or without panic disorder), with the highest rates in the offspring of parents with depression only. Parental depression independently predicted new onset of depression, parental panic disorder independently predicted new onset of social phobia, and the two interacted to predict new onset of specific phobia and generalized anxiety disorder.
CONCLUSIONS:
At-risk offspring continue to develop new disorders as they progress through adolescence. These results support the need to screen and monitor the offspring of adults presenting for treatment of panic disorder or major depressive disorder.
In recent years many studies have focused on brain activity differences between fluent and dyslexic readers in order to understand the neural basis of dyslexia. The aim of the current study was to examine the processing of words and pseudo-words in the two hemispheres among dyslexic as compared to fluent readers, using behavioral, and electrophysiological source estimation measures. Two matched groups of university students, fluent and dyslexic readers, performed a lexical decision task in order to examine the processes of word recognition. Dyslexic readers showed overall less activity than fluent readers, mainly during late processing stages. In addition, the distinctive patterns of activity for words and pseudo-words displayed by fluent readers were not apparent in dyslexic readers. In particular, the increased activation of left-hemisphere language areas found in response to pseudo-words was absent in dyslexics. These findings are further evidence of orthographic and phonological impairments in dyslexia.
Two matched groups of university students, fluent and dyslexic readers, showed significant differences in brain activation when reading words and pseudo-words. Dyslexic readers showed overall less brain activity than fluent readers while processing both words & pseudo-words, especially pseudo-words. These findings are further evidence of orthographic and phonological impairments in dyslexia.
OBJECTIVE:
The role of visual processing deficits in dyslexia remains unclear and continues to stir controversy. Most studies to date have used alphabetic and or other language-dependent patterns. The current study compares how dyslexics and regular readers process non-alphabetic visual patterns.
METHODS:
The stimuli were black and white drawings, 50 meaningful (concrete objects) and 50 meaningless (pseudo-objects with no linguistic name) presented visually on a computer screen. Measures included behavioral accuracy and reaction time, event-related potential (ERP), and low resolution electromagnetic tomography (LORETA). The subjects were 15 dyslexic and 15 aged-matched regular readers.
RESULTS:
The dyslexics exhibited significantly longer reaction time and shorter latencies of P1 and P2 components to both objects and pseudo-objects compared to the regular readers. Data from the LORETA solution analysis indicated significantly different brain activity between the two groups: both exhibited higher left hemisphere activation when viewing objects compared to pseudo-objects; and dyslexics exhibited lower left hemisphere activation when viewing objects and higher right hemisphere activation when viewing pseudo-objects during the early stages of processing.
CONCLUSIONS:
The results support the notion that brain activation of dyslexic readers differs from that of the regular readers when processing non-alphabetic patterns, and that the differences appear from the early stage of processing.
SIGNIFICANCE:
These results emphasize that differences in brain activity between dyslexic and regular readers can be seen even in a non-alphabetic task, and in early stages of processing.
Copyright © 2010 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.
Brain activity during processing objects and pseudo-objects was significantly different between adult regular and dyslexic readers. The dyslexics exhibited significantly longer reaction time and shorter latencies to both objects and pseudo-objects. And dyslexics exhibited lower left hemisphere brain activation when viewing objects and higher right hemisphere activation when viewing pseudo-objects during the early stages of processing.
Dr Levinson wondered: While very important, these and related data do not yet attempt to clearly distinguish between whether these processing times and brain activation potentials are primary, secondary or resultant dysfunctional vs. compensatory phenomena.
Objective:
The existence of neuropsychological deficits has been implicated in obsessive-compulsive disorder (OCD), particularly memory, attention, and executive functions. However, few studies have focused on neuropsychological deficits in the relatives of OCD patients. The aim of this study was to investigate cognitive deficits in OCD patients and their parents.
Methods:
Forty patients with OCD, 48 parents of these patients, and 87 healthy controls completed a neuropsychological testing battery.
Results:
Both OCD patients and their parents showed impairments in delayed verbal memory and delayed visual memory. Furthermore, they performed worse than healthy controls in problem-solving ability.
Dr Levinson suggests these results support his research indicating a correlation of anxiety disorders with dyslexia and cerebellar-vestibular dysfunction
Conclusion:
Our study demonstrated familial aggregation of delayed memory deficits and impaired problem-solving ability, which may be the potential neuropsychological endophenotypes of hereditary susceptibility to OCD.
The primary reflex system emerges during fetal life and is inhibited during the first year after birth. Our aim was to examine the effects of persistence of this early neurological system on the attainment of core literacy skills in dyslexic and non-dyslexic poor readers. We assessed the prevalence of a persistent primary reflex in a cross-sectional, representative sample of children (n=739) aged 7-9 years old attending mainstream primary school in Northern Ireland using standardised educational tests, and a clinical diagnostic test for a primary reflex (the asymmetrical tonic neck reflex (ATNR)). Multiple regression analyses, involving all of the sample children, revealed that persistence of the ATNR was significantly predictive of attainments in reading (t=-8.34, p<.001), spelling (t=-8.00, p<.001), non-word reading (t=-16.15, p<.001), and verbal IQ (t=-4.71, p<.001). ANOVA tests revealed that there were no differences between the performance of dyslexic and non-dyslexic poor readers on any of the outcome measures (reading (F(1, 289)=0.51, p=.48), spelling (F(1, 289)=0.02, p=.90), non-word reading (F(1, 289)=0.76, p=.38), ATNR level (F(1, 289)=2.54, p=.11)). Further ANOVA tests revealed that males had significantly higher levels of persistent reflex than females (F(1, 737)=15.21, p<.001), and that children from socially disadvantaged backgrounds had significantly higher levels of reflex than children who were not socially disadvantaged (F(1, 737)=20.84, p<.001). The findings suggest that for many children in mainstream schooling, the attainment of core educational skills may be affected by the persistence of a brainstem mediated reflex system that should have been inhibited in the first year after birth. Furthermore, these findings suggest that dyslexia is not a distinct category of poor reading, and that it may be more valid to term all poor readers as dyslexic irrespective of IQ.
The primary reflex system emerges during fetal life and is inhibited during the first year after birth. In a representative samples of 739 children aged 7-9 years, the persistence of a primary reflex (the asymmetrical tonic neck reflex (ATNR)) of brain stem origin correlated with mild and severe dyslexic literary scores. Males and children from socially disadvantaged backgrounds had significantly higher levels of persistent reflex than females.These findings suggest that dyslexia is not a distinct category of poor reading, and that it may be more valid to term all poor readers as dyslexic irrespective of IQ.
According to Dr Levinson: These data suggest that dyslexia is independent of reading scores, that males and the socially disadvantaged may be more developmentally delayed and so manifest higher frequencies of reading/ learning disorders, and even that dyslexia may contribute to becoming or remaining socially disadvantaged. Since the cerebellum significantly modulates midbrain functioning and reflexes, the correlation of these primitive reflexes with poor literacy may highlight an overlooked cerebellar determinant.
RESULTS: Children with occasional therapy demonstrated higher levels of school phobia when their knowledge was tested than those receiving continuous or no therapy. Girls revealed a higher level of school phobia and knowledge testing fear, regardless of their therapeutic experience.
Dr Levinson's commentary: In this study, no reasons were given for the specific results found. According to my research, all types of phobias are more common in dyslexics since both disorders are triggered by cerebellar-vestibular dysfunctioning. Females are more predisposed to anxiety disorders or intensity whereas the opposite appears true for dyslexia.
Results: No significant association of primary headaches was found with asthma and allergic disorders, convulsive episodes, sleep disorders and increased body weight. Overall behavioral disorders as well as anxiety and depression, but not other psychiatric disorders, were more common in children who experienced headache than in controls.
DR LEVINSON'S COMMENT: My clinical studies have similarly noted that Dyslexia, LD, ADHD and related Anxiety and Depressive Disorders of cerebellar-vestibular origin are most frequently correlated to primary headaches because they all share a common neurophysiological origin.
Trauma is one of the leading reasons for emergency department (ED) visits in children. Hyperactivity, inattentiveness and impulsiveness may contribute to injury proneness.
CONCLUSION: The data suggest that children who make repeated trauma-related ED visits have a predisposition to ADHD, and they may benefit from screening for this disorder while in the ED.
DR LEVINSON'S COMMENT: Because ADHD & DYSLEXIA have cerebellar-vestibular dysfunctioning, impaired balance & dyscoordination or clumsiness may also contribute to accident proneness.
Elevated Background Noise in Patients
With ADHD: A Neuronal Correlate for Inattention
Speaker: Emanuel Bubl, M.D.
EDUCATIONAL OBJECTIVE:
At the conclusion of the session, the participant should be able to: 1) Why the eye is so useful in finding a diagnostic marker in psychiatry; 2) Identify the potential neural correlate of inattention; 3) Why there is a need for an objectively measurable surrogate marker in psychiatry
SUMMARY:
Background Inattention and distractibility belong among the core symptoms of attention-deficit/hyperactivity disorder (ADHD); still a neuronal correlate is largely unknown. An elevated noise ratio has been proposed as underlining pathophysiological correlate. Methods 20 patients with the diagnosis of attention deficit disorder and 20 matched healthy subjects were studied. The pattern electroretinogram (PERG) derived noise was obtained in patients with ADHD and a matched control group. The PERG is an electrophysiological measurement for the activity of the retinal ganglion cells. PERGs were recorded in steady state mode in response to checkerboard stimuli at 12 reversals/s. Results Patients with attention deficit disorder displayed significantly elevated noise. The signal correlated highly with the psychometric measures for ADHD especially for inattention.
Conclusions:
Here we report the novel finding of altered visual signal processing in patients with ADHD at a very early neuronal level. The data provide evidence that elevated background noise is associated with inattention and might turn out as neuronal correlate for inattention in ADHD.