Inspection time in non-demented older adults with mild cognitive impairment

The aim of this study was to examine inspection time (IT) performance in older adults with mild cognitive impairment (MCI), who are at higher risk of developing further cognitive decline or dementia. IT is described as an index of speed of informational intake. IT correlates with measures of fluid intelligence and is possibly a marker for the integrity of the cholinergic system of the brain. IT may therefore be useful in aiding the diagnosis of early-stage progressive cognitive impairment. The current study compares IT in 28 people with MCI to 28 age, gender and education-matched controls. The computer-based, visual IT task required participants to discriminate between two visual stimuli that were presented for brief periods. Participants' IT performance was compared to their performance on cognitive and memory tasks. Group comparison showed that participants with MCI performed significantly worse on IT than controls and was not affected by years of education. In combination with other clinical, neuropsychological and biological tests, IT may be a useful assessment tool for improving the identification of older adults at risk for clinically relevant cognitive decline.     

Cognitive impairment and EEG background activity in adults with Down's syndrome: a topographic study

Objective: Studies correlating electroencephalographic (EEG) data and cognitive performance in Down's syndrome (DS) showed conflicting results. The aims of this study were to investigate the sources of EEG rhythms in adults with DS at three dimensional representation of current source density (CSD) using exact/standard Low Resolution Electromagnetic Tomography (e/sLORETA), and their correlation with cognitive performance. Methods: Twenty‐five adults with DS underwent a neuropsychological battery and 5 min of resting, eye‐closed 29‐channel EEG were recorded. After e/sLORETA analysis, data were compared with those from age and gender‐matching control subjects as following: absolute and relative power in delta (1–3 Hz), theta (4–7 Hz), alpha1 (8–9 Hz), alpha2 (10–12 Hz), beta1 (13–18 Hz), beta2 (19–21 Hz), beta3 (22–30 Hz); alpha and theta bands adjusted to individual alpha peak frequency (IAF). Current source activities in DS group in regions showing significant differences compared with controls underwent correlation analysis with psychometric scores. Results: In DS, IAF was shifted to lower frequencies and correlated positively with Wechsler Adult Intelligence Scale and Mini‐Mental State examination. Compared with controls, DS showed increased CSD in: theta, alpha‐1, and beta1 classical bands and in IAF‐adjusted bands, while relative alpha2 was decreased. A negative correlation between cognitive performance and theta/alpha CSD in the right frontal lobe and right posterior cingulate cortex was found. The relative alpha2 correlated positively with cognitive tests. Conclusions: Increased CSD in DS, correlating with cognitive performance, for both slow and fast rhythms suggests involving of cortical and subcortical mechanisms. LORETA might be useful for objective measure of cognitive decline in DS. Hum Brain Mapp, 2011. © 2010 Wiley‐Liss, Inc.     

Neuropsychological performance in adults with Tourette's syndrome

Neuropsychological performance was examined in a sample of 36 adults who met DSM-III-R criteria for Tourette's syndrome (TS), confirmed by a psychiatrist or a neurologist. All subjects were administered an extensive battery of psychological and neuropsychological tests as well as symptom rating scales. The mean performance on most tests was within normal limits, and the patients and controls did not differ on a summary measure of neuropsychological performance. However, apparently 20% of the TS subjects had mild abnormalities on a summary measure of neuropsychological performance. These data are consistent with recent reports of generally normal performance in children with TS. Poor performance on several tasks was related to later age at symptom onset. The results were discussed with regard to the nature of the sample and directions for future research.     

Nocturnal periodic breathing in adults with Down's syndrome

ABSTRACT. Nineteen adults with Down's syndrome were studied with the static charge sensitive bed (SCSBl method. A single whole-night recording was made of each subject. Two different periodic breathing indices (PBIf and PBI%) were calculated from a computerized analysis of these recordings. A polygraphic recording was also made of one subject, a 52-year-old male. The EEC, the EOG, the EMG, nasal and oral airflow, and diaphragmatic movement were recorded, the latter with an abdominal strain gauge and with the SCSB-method simultaneously. Good correlation was found between the recording with the SCSB and the strain gauge. The apnoea index (AI calculated from the polygraphic recording was 23.3, while the PBIf of this patient recorded on another night and analysed automatically was 45 and the PBI% was 78.6. The patient group was divided into those aged 40 or older (n= 10) and those aged 39 or younger (n=9). The mean PBI% of the older group was 24.0 while that of the younger group was 5.4 (t = 2.23; P<0.05). The mean PBIf of the older group was 16.7 and that of the younger was 3.6 (i=2.70; P=<0.02). The mean body mass index (BMI) of the younger group was significantly higher than the mean BMI of the older group. The mean BMI of those patients, whose FBI values were considered to be normal (PBI% <3, PBIf <7), did not significantly differ from the BMI of those patients, whose PBI-values were abnormal. There were four patients with tonsillar or lingual hypertrophy in the older age group and five in the younger. The mean FBI-values between those with and those without narrowing of the upper airways did not differ significantly. The study thus indicated that age is the most significant factor favouring the development of periodic breathing during sleep in patients with Down's syndrome.     

Normal ageing in adults with Down's syndrome: a longitudinal study

The ubiquitous presence of the neuropathoiogy of Alzheimer disease (AD) in individuals with Down's syndrome (DS) over 40 years of age suggests that this group of people will exhibit a high prevalence of dementia of the Alzheimer type (DAT) as they age. The present study indicates that there is a clear discrepancy between the presumed presence of AD neuropathoiogy and the clinical expression of DAT among older people with DS. In the first 6 years of a longitudinal study, the present authors compared 91 adults (31–63 years of age) with DS and mild or moderate mental retardation to 64 adults (3 l –76 years of age) with other forms of mental retardation (MR) on yearly measures of mental status, short-and long-term memory, speeded psychomotor function, and visuospatial organization. The results indicated that, over repeated testing on the verbal long–term memory test, younger participants with DS showed small increases in their scores, while older participants with DS showed very slight decreases. Overall performance scores on this test and a speeded psychomotor task were poorer for both diagnostic groups in individuals aged SO years and older. The magnitude and type of these selective changes in performance were consistent with performance profiles observed in older healthy adults without mental retardation on tests measuring similar cognitive functions. Only four out of the 91 people with DS in the present sample showed changes in funaioning that have led to a diagnosis of possible DAT. and in these individuals, alternative causes of performance declines were concurrently present (e.g, thyroid dysfunction). These findings indicate that some age–associated changes in funaioning are related to ‘normal’ but probably precocious ageing among adults with DS. Furthermore, these findings suggest that adults with DS and mild or moderate mental retardation may be at lower risk for dementia during their fourth and fifth decades of life than previous studies have suggested.     

Neuropsychological profiles of adults with Klinefelter syndrome.

Children and adolescents with Klinefelter syndrome (XXY) have been reported to show deficits in language processing including VIQ < PIQ and a learning disability in reading and spelling. However, whether this is characteristic of adults with Klinefelter syndrome has not been established. Thirty-five men with Klinefelter syndrome, aged 16 to 61, and 22 controls were evaluated with a comprehensive neuropsychological battery. The Klinefelter patients scored significantly below controls in language skills, verbal processing speed, verbal and nonverbal executive abilities, and motor dexterity. Within the Klinefelter sample, three cognitive subgroups were identified: VIQ 7 or more points below PIQ (n = 10), VIQ within 6 points of PIQ (n = 12), and PIQ 7 or more points below VIQ (n = 12). The deficits detected in language, verbal processing speed, and verbal executive skills were found to be isolated to the VIQ < PIQ subgroup, while the abnormalities in motor dexterity and nonverbal executive skills were confined to the PIQ < VIQ subgroup. Older age was significantly correlated with increases in VIQ relative to PIQ in the patient group, which suggests the intriguing possibility that the PIQ < VIQ subgroup primarily emerges in young adulthood, perhaps in response to the reported hormonal abnormalities detected in Klinefelter syndrome patients during puberty.     

Cervical spine abnormalities in institutionalized adults with Down's syndrome

ABSTRACT. The prevalence of increased anterior atlanto-odontoid distance (AAOD), a risk factor for spinal cord compression, and degenerative disease of the cervical spine (DDCS) in a population of institutionalized adults with Down's syndrome (DS) was determined and compared with age- and sex-matched'normals'presenting to a hospital emergency department. Radiographs of the cervical spines of 99 adults with DS and 198'normals'were compared using a standardized rating scale. The prevalence of an AAOD of 3 mm or greater, the threshold of risk from the literature, was 8% for DS cases and 2% for controls (P<0.01). The mean AAOD for DS cases was 2.0±l mm and for controls l.5±0.5 mm (P<0.01). There was a negative correlation between AAOD and age of DS cases. The prevalence of any degree of DDCS among the DS cases was 64%, the controls 39% (P<0.001); for moderate or severe DDCS the prevalence among DS cases was 45%, controls 12% (P<0.001). The prevalence of DDCS increased with age in both groups, but the severity of DDCS was significantly greater for DS individuals in all age groups. The levels of the cervical spine affected ranged from C2 to C6; the most commonly affected level was C5-C6. While DS adults are at increased theoretical risk for spinal cord compression due to increased AAOD, its clinical significance would appear to be small and to decline with age. Of more concern is the high prevalence of DDCS; adults with DS are at high risk for this condition and consideration should be given to this diagnosis in the appropriate clinical setting.     

Manual and oral praxis in adults with Down's syndrome

Mentally handicapped adults with and without Down's syndrome performed single movements and movement sequences following both verbal and demonstration cueing conditions. While the type of cue did not influence the performance of control subjects. Down's syndrome individuals exhibited more error following verbal cueing. These findings could not be explained on the basis of verbal encoding differences between the groups. The results support the notion that Down's syndrome persons suffer from a dissociation of the functional system responsible for speech perception and the system involved with the organization of complex movement.     

Sleep patterns in mental retardation: Down's syndrome.

EEG and eye movements during two consecutive nights were recorded in 21 "normal" and 21 Down's subjects of both sexes in the 14-24-year age range. Records of most Down's subjects were characterized by longer total sleep time, lack of waking alpha, frequent awakening and movement epochs and fewer spindle bursts. Significantly longer "awake" and stage 4 percentages, but less stage 2, were found in the Down's group. They also had longer REM latency, and lower eye movement density based on number of eye movements. Density based on integrated eye activity correlated positively with IQ in the Down's subjects. Spectrum analysis for EEG frequencies from 1 to 20 c/sec showed significantly greater power in the Down's group below 9 and above 12 c/sec, but no difference in the alpha range. The greater power at low frequencies was more pronounced in "awake", stage 1 and REM.     

Brain-stem auditory evoked potentials in adults with Down's syndrome.

Brain-stem auditory evoked potentials (BAEPs) were examined in 37 adult patients with Down's syndrome and in 37 age-matched normal subjects. All absolute and interpeak latencies except for the interpeak latency IV-V were shorter in patients than in normal subjects. The amplitude of wave V and the amplitude ratio V/I were smaller in patients than in normal subjects. Short latencies in patients were considered to be due to the smaller size of the brain-stem or to faster conduction velocity. The prolonged interpeak latency IV-V and the smaller wave V may indicate physiological dysfunctions between the upper pons and the lower midbrain.     

Working memory and everyday cognition in adults with Down's syndrome

A number of previous studies have suggested that young people with Down's syndrome (DS) have a specific deficit of the phonological loop component of the working memory. However, there have also been studies which have proposed a specific deficit of the central executive component of working memory and suggested similarities of working memory functioning with patients with Alzheimer's disease. Fifteen middle‐aged people with DS were matched for their individual scores of non‐verbal intelligence to 15 individuals with mixed aetiology of intellectual disability. A versatile range of tasks was used in order to evaluate the functioning of working memory components. In addition, several everyday cognition skills were assessed. The subjects with DS performed significantly more poorly in all tasks assessing the phonological loop. Performance in other working memory tasks and compound variables representing different working memory components was equal in the groups. In addition, both groups had equal everyday cognition skills. The functioning of the phonological loop seems to be clearly deficient in people with DS. Interestingly, the deficit does not seem to affect the vocabulary or other everyday cognition skills in individuals with DS. No signs of specific deficit of the central executive component of working memory were found.     

Sequence of cognitive decline in dementia in adults with Down's syndrome

Adults with Down's syndrome (DS) are known to be at risk of dementia of the Alzheimer type (DAT), but because of their lifelong intellectual deficits, it is difficult to determine the earliest signs and characteristics of age‐associated decline and dementia. In a longitudinal study in which all participants were healthy at the time of their entry into the study, the present authors compared the amount of decline on the subtests of the WISC‐R to determine the sequence of cognitive decline associated with varying stages of dementia. Twenty‐two individuals with varying degrees of cognitive decline were compared to 44 adults with DS who have remained healthy. All participants functioned in the mild or moderate range of intellectual disability at initial testing. On each subtest of the WISC‐R, the amount of change experienced by the healthy participants over the study period was compared to the amount of change found for each of the groups with decline. Out of the individuals who showed declines, 10 adults with DS were classified as having ‘questionable’ decline based on the presence of memory impairment, and five and seven adults with DS were classified as in the ‘early stage’ and ‘middle stage’ of DAT, respectively, based on the presence of memory impairment, score on the Dementia Scale for Down Syndrome and a physician's diagnosis. It was found that participants who were identified as ‘questionable’, in addition to the memory loss that determined their classification, also showed significant declines on the Block Design and Coding subtests. The five adults in the early stage of dementia showed declines on these subtests, and in addition, on the Object Assembly, Picture Completion, Arithmetic and Comprehension subtests. The seven adults in the middle stage of dementia showed declines on these subtests, plus declines on Information, Vocabulary and Digit Span subtests. The Picture Arrangement and Similarities subtests were not useful in distinguishing between the groups because of baseline floor effects for a substantial proportion of participants. The present longitudinal study showed a sequence of cognitive decline associated with DAT, beginning with a possible ‘pre‐clinical’ stage, and progressing through the early and middle stages. This approach begins to define the sequence of declining cognitive capacities that contributes to the observed functional deterioration caused by Alzheimer's disease and that is likely to reflect the involvement of cortical areas as the disease progresses.     

Basal metabolic rate in healthy Down's syndrome adults

ABSTRACT. Basal metabolic rale (BMR) was measured on 2 consecutive Jays with an open-circuit, indirect calorimeter in 16 healthy subjects with trisomy 21 Down's syndrome (DS) aged 22-35 years and 11 healthy control volunteers aged 20-31 years. BMR measurements Jut mil differ on consecutive days in either the DS or control groups. Absolute BMR, BMR corrected for surface area, and HMR corrected tor lean body mass did not differ between the DS subjects and the volunteers. The per cent of predicted BMR also did not Jitter between the two groups. These results suggest that systems controlling basal metabolism are not affected by extra gcnomic material from chromosome 21.     

Preliminary evaluation of a scale to assess cognitive function in adults with Down's syndrome: the Prudhoe Cognitive Function Test

Background In the clinical diagnosis of dementia in Down's syndrome (DS), it may be difficult to distinguish between cognitive deterioration and the various degrees of pre‐existing intellectual disability (ID). Serial measurements of both cognitive function and behaviour are required. The aim of the present study was to evaluate the performance of non‐demented adults with DS on a subject‐directed instrument, the Prudhoe Cognitive Function Test (PCFT), preliminary to its serial use in a prospective study. Methods From 1985 to 1986, 85 non‐demented hospitalized adults with DS were interviewed using the PCFT. The Adaptive Behavior Scale (ABS) was administered to the carers. The subjects’ levels of ID (graded from mild through moderate, severe and profound to untestable) were based on their scores on the Stanford–Binet Intelligence Scale, as reported in the medical records, and the relationship between level of disability and performance on the PCFT and ABS, and their respective domains, was examined. Results Both scales produced a wide range of scores and the correlation between them was highly significant. Both scales correlated highly significantly with the degree of ID, but more subjects with high levels (i.e. profound to untestable) of disability obtained very low or zero scores on the PCFT and its domains than on the ABS. Conclusions The PCFT provides a reliable quantitative measure of cognitive function in subjects with DS, and could be a useful adjunct to the diagnosis of dementia in prospective studies. However, the almost uniformly low scores obtained by those with high levels of ID suggests that its power to detect cognitive decline will be limited to those who are less disabled, while the ABS may be more useful than the PCFT in detecting deterioration in people with profound ID.     

Cerebrospinal fluid monoaminergic metabolites are elevated in adults with Down's syndrome

Under conditions of rest and a low monoamine diet, brain monoamine activity was examined in young (less than 35 years) and old (greater than 35 years) adults with Down's syndrome and in control subjects by measuring the cerebrospinal fluid (CSF) and plasma concentrations of the neurotransmitter norepinephrine, and of 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), and 3-methoxy 4-hydroxyphenylglycol (MHPG), the respective metabolites of the neurotransmitters serotonin, dopamine, and norepinephrine. There were no age-related differences in metabolite concentrations in either the Down's syndrome or control subjects. CSF concentrations of 5-HIAA, HVA, and norepinephrine were significantly higher in young subjects with Down's syndrome as compared with young controls, and CSF concentrations of 5-HIAA and norepinephrine were significantly higher, by twofold or more, in old subjects with Down's syndrome as compared with older controls. The results suggest that monoamine turnover and brain functional activity involving monoamines is elevated in Down's syndrome, and that the early neuropathological changes in the disorder are not associated with a monoamine deficit.