Reliability and factor structure of the Short Problem Behaviors Assessment for Huntington's disease (PBA-s) in the TRACK-HD and REGISTRY studies.

The authors report the inter-rater reliability and factor structure of the Short Problem Behaviors Assessment (PBA-s), a semistructured interview to measure severity and frequency of behavioral problems in Huntington's disease. Video recordings of 410 PBA-s interviews were rescored by an independent rater, and Cohen's kappa calculated to assess inter-rater reliability. The mean kappa was 0.74 for severity and 0.76 for frequency scores, whereas weighted kappa (allowing scores to differ by 1 point) was 0.94 for severity and 0.92 for frequency scores. The results of factor analysis were consistent with previous studies using other measures. The authors conclude that the PBA-s is a reliable measure.

Unified Huntington's disease rating scale for advanced patients: validation and follow-up study.

The Unified Huntington's Disease Rating Scale (UHDRS) adequately measures decline in patients at early and moderate stages of Huntington's disease (HD). In advanced patients, floor effects hamper the evaluation, thus calling for an adjusted scale. We designed the UHDRS-For Advanced Patients (UHDRS-FAP), in order to improve longitudinal assessment of patients at advanced disease stage. Sixty-nine patients with a Total Functional Capacity (TFC) ≤ 5 were recruited in France and in the Netherlands. Among them, 45 patients were followed longitudinally (mean 1.6 ± 1.2 years) with the UHDRS-FAP; 30 were also assessed with the UHDRS. Cross-sectional analyses evaluated psychometric properties and interrater reliability of the scale. Longitudinal analyses evaluated the sensitivity to decline compared to the UHDRS. Internal consistency was higher for motor and cognitive scores than for somatic and behavioral scores (0.84, 0.91, 0.70, and 0.49, respectively). Interrater reliability was ≥ 0.88 in all scores. The somatic score, specific to the UHDRS-FAP, declined over time, as well as motor and cognitive performance with both scales. Although performance with the 2 scales correlated, the UHDRS-FAP appeared more sensitive to change and was the only scale that detected decline in patients with a TFC ≤ 1. Neither scale detected a significant decline in behavioral scores. The UHDRS-FAP is reliable and more sensitive to change than the original UHDRS for cognitive and motor domains. It offers items relevant for daily care. Behavioral scores tended to decline but this may reflect the decline in the communicative abilities of the patients.

The unified Huntington's Disease Rating Scale for advanced patients: validation and follow-up study.

The Unified Huntington's Disease Rating Scale (UHDRS) adequately measures decline in patients at early and moderate stages of Huntington's disease (HD). In patients with advanced HD, floor effects hamper the evaluation, thus calling for an adjusted scale. We designed the UHDRS-For Advanced Patients (UHDRS-FAP) to improve longitudinal assessment of patients at the advanced disease stage. Sixty-nine patients with a Total Functional Capacity score ≤ 5 were recruited in France and the Netherlands. Among them, 45 patients were followed longitudinally (mean ± standard deviation, 1.6 ± 1.2 years) with the UHDRS-FAP; 30 patients also were assessed with the UHDRS. In cross-sectional analyses, the psychometric properties and inter-rater reliability of the scale were evaluated. Longitudinal analyses were used to evaluate the sensitivity to decline of the UHDRS-FAP compared with the UHDRS. Internal consistency was higher for motor (0.84) and cognitive (0.91) scores than for somatic (0.70) and behavioral (0.49) scores. Inter-rater reliability was ≥ 0.88 for all scores. The somatic score, which was specific to the UHDRS-FAP, declined over time along with motor and cognitive performance on both scales. Although performance with the two scales was correlated, the UHDRS-FAP appeared to be more sensitive to change and was the only scale that detected decline in patients with a Total Functional Capacity score ≤ 1. Neither scale detected a significant decline in behavioral scores. The results indicate that the UHDRS-FAP is reliable and more sensitive to change than the original UHDRS for cognitive and motor domains. It offers items that are relevant for daily care. Behavioral scores tended to decline, but this may reflect the decline in patients' communicative abilities.

Confabulation in Alzheimer's disease and amnesia: a qualitative account and a new taxonomy.

Clinical and experimental observation have shown that patients who confabulate, especially but not exclusively when provoked by specific questions, retrieve personal habits, repeated events or over-learned information and mistake them for actually experienced, specific, unique events. Accordingly, the aim of this study is to characterize and quantify the relative contribution of this type of confabulation, which we refer to as Habits Confabulation (HC), to confabulations produced by 10 mild Alzheimer's disease (AD) patients and 8 confabulating amnesics (CA) of various etiologies. On the Confabulation Battery (Dalla Barba, 1993a, Dalla Barba & Decaix, 2009), a set of questions involving the retrieval of various kinds of semantic and episodic information, patients produced a total of 424 confabulation. HC accounted for 42% and 62% of confabulations in AD patients and CA, respectively. This result indicates that, regardless the clinical diagnosis, the brain pathology or their lesion's site, confabulation largely reflects the individuals' tendency to consider habits, routines, and over-learned information as unique episodes. These results are discussed in the framework of the Memory Consciousness and Temporality Theory (Dalla Barba, 2002).

Temporal consciousness and confabulation: is the medial temporal lobe "temporal"?

Since the early descriptions of this phenomenon, there is a large consensus on the distinction between two forms of confabulation. Provoked confabulations are plausible minor memory distortions in response to direct questioning, whereas spontaneous confabulations are unprovoked, often implausible, memories. However, as we show with the analysis of 284 provoked and 52 spontaneous confabulations produced by eight patients with confabulatory syndromes of different aetiologies, the provoked/spontaneous distinction fails to capture the quality of the great majority of confabulations that clearly do not fall in either of the two poles of the distinction. In this study, the majority of provoked (52%) and spontaneous (73%) confabulations consisted of what we refer to as "general memories, habits, and misplacements", i.e., either true episodes misplaced in time and place, or personal habits and routines which are considered by the patient as specific personal episodes. These observations are discussed within the framework of the Memory, Consciousness, and Temporality Theory. According to this theory, confabulation reflects an abnormal functioning of temporal consciousness (TC). The integrity of the medial temporal lobe (MTL) and related structures is crucial for the normal functioning of TC. Data from the literature show that what confabulators have in common is not a specific lesion site but rather the integrity of the MTL, which is consistent with the idea that the MTL is essential for the function of normal and confabulatory TC. In this sense the MTL is "temporal", because its integrity allows individuals to be consciously aware of a personal past, present and future. A better understanding of TC, including its neurobiological correlates, will help to better understand confabulation avoiding theoretically untenable and experimentally undemonstrated explanatory idols like memory traces and unconscious monitoring.

Effect of fetal neural transplants in patients with Huntington's disease 6 years after surgery: a long-term follow-up study.

BACKGROUND: Although we have shown in three out of five patients with Huntington's disease that motor and cognitive improvements 2 years after intracerebral fetal neural grafts are correlated with recovery of brain metabolic activity in grafted striatal areas and connected regions of the cerebral cortex, neural grafts are not known to have protective effects on the host brain per se. We undertook long-term follow-up of previously reported patients with the disease to ascertain the nature and extent of any secondary decline after grafting. METHODS: Five patients with Huntington's disease from our pilot study were assessed annually with the unified Huntington's disease rating scale, neuropsychological tests, and MRI, for up to 6 years after neural grafting. Resting cerebral activity was recorded at 2 and 6 years. FINDINGS: Clinical improvement plateaued after 2 years and then faded off variably 4-6 years after surgery. Dystonia deteriorated consistently, whereas chorea did not. Cognitive performance remained stable on non-timed tests, whereas progression of motor disability was shown by deterioration on timed tests. Hypometabolism also affected the brain heterogeneously, sparing the benefits in the frontal cortex and at the precise location of the grafts, but showing a progressive deterioration in other areas. Two patients who had no benefit from grafting at 2 years continued to decline in the same way as non-grafted patients. INTERPRETATION: Neuronal transplantation in Huntington's disease provides a period of several years of improvement and stability, but not a permanent cure for the disease. Improvement of the surgical procedure and in patient selection could improve the therapeutic value, but neuroprotective treatment seems to be unavoidable in the disease.

The role of the striatum in rule application: the model of Huntington's disease at early stage.

The role of the basal ganglia, and more specifically of the striatum, in language is still debated. Recent studies have proposed that linguistic abilities involve two distinct types of processes: the retrieving of stored information, implicating temporal lobe areas, and the application of combinatorial rules, implicating fronto-striatal circuits. Studies of patients with focal lesions and neurodegenerative diseases have suggested a role for the striatum in morphological rule application, but functional imaging studies found that the left caudate was involved in syntactic processing and not morphological processing. In the present study, we tested the view that the basal ganglia are involved in rule application and not in lexical retrieving in a model of striatal dysfunction, namely Huntington's disease at early stages. We assessed the rule-lexicon dichotomy in the linguistic domain with morphology (conjugation of non-verbs and verbs) and syntax (sentence comprehension) and in a non-linguistic domain with arithmetic operations (subtraction and multiplication). Thirty Huntington's disease patients (15 at stage I and 15 at stage II) and 20 controls matched for their age and cultural level were included in this study. Huntington's disease patients were also assessed using the Unified Huntington's Disease Rating Scale (UHDRS) and MRI. We found that early Huntington's disease patients were impaired in rule application in the linguistic and non-linguistic domains (morphology, syntax and subtraction), whereas they were broadly spared with lexical processing. The pattern of performance was similar in patients at stage I and stage II, except that stage II patients were more impaired in all tasks assessing rules and had in addition a very slight impairment in the lexical condition of conjugation. Finally, syntactic rule abilities correlated with all markers of the disease evolution including bicaudate ratio and performance in executive function, whereas there was no correlation with arithmetic and morphological abilities. Together, this suggests that the striatum is involved in rule processing more than in lexical processing and that it extends to linguistic and non-linguistic domains. These results are discussed in terms of domain-specific versus domain-general processes of rule application.

Awareness of memory deficits in early stage Huntington's disease.

Patients with Huntington's disease (HD) are often described as unaware of their motor symptoms, their behavioral disorders or their cognitive deficits, including memory. Nevertheless, because patients with Parkinson's disease (PD) remain aware of their memory deficits despite striatal dysfunction, we hypothesize that early stage HD patients in whom degeneration predominates in the striatum can accurately judge their own memory disorders whereas more advanced patients cannot. In order to test our hypothesis, we compared subjective questionnaires of memory deficits (in HD patients and in their proxies) and objective measures of memory dysfunction in patients. Forty-six patients with manifest HD attending the out-patient department of the French National Reference Center for HD and thirty-three proxies were enrolled. We found that HD patients at an early stage of the disease (Stage 1) were more accurate than their proxies at evaluating their own memory deficits, independently from their depression level. The proxies were more influenced by patients' functional decline rather than by patients' memory deficits. Patients with moderate disease (Stage 2) misestimated their memory deficits compared to their proxies, whose judgment was nonetheless influenced by the severity of both functional decline and depression. Contrasting subjective memory ratings from the patients and their objective memory performance, we demonstrate that although HD patients are often reported to be unaware of their neurological, cognitive and behavioral symptoms, it is not the case for memory deficits at an early stage. Loss of awareness of memory deficits in HD is associated with the severity of the disease in terms of CAG repeats, functional decline, motor dysfunction and cognitive impairment, including memory deficits and executive dysfunction.

Long-term persistence of vaccine-derived aluminum hydroxide is associated with chronic cognitive dysfunction.

Macrophagic myofasciitis (MMF) is an emerging condition, characterized by specific muscle lesions assessing long-term persistence of aluminum hydroxide within macrophages at the site of previous immunization. Affected patients mainly complain of arthromyalgias, chronic fatigue, and cognitive difficulties. We designed a comprehensive battery of neuropsychological tests to prospectively delineate MMF-associated cognitive dysfunction (MACD). Compared to control patients with arthritis and chronic pain, MMF patients had pronounced and specific cognitive impairment. MACD mainly affected (i) both visual and verbal memory; (ii) executive functions, including attention, working memory, and planning; and (iii) left ear extinction at dichotic listening test. Cognitive deficits did not correlate with pain, fatigue, depression, or disease duration. Pathophysiological mechanisms underlying MACD remain to be determined. In conclusion, long-term persistence of vaccine-derived aluminum hydroxide within the body assessed by MMF is associated with cognitive dysfunction, not solely due to chronic pain, fatigue and depression.

Cognitive impairment related to apathy in early Huntington's disease.

OBJECTIVE: To investigate the relationships between cognitive impairment and apathy in patients with early Huntington's disease (HD) and to further explore the influence of depression on the outcome of cognitive changes associated with apathy. METHODS: We included 36 early HD patients, among them 20 were apathetic (HDA) and 16 were not (HDnA). The two groups were matched by age, education and severity of disease. Cognitive functions were evaluated by a comprehensive neuropsychological battery that measures memory, attention, executive function, language and visuospatial abilities. RESULTS: The HDA patients had significantly lower scores on memory, attention and executive function tests when compared with the HDnA patients (p values <0.05). We compared the performance of patients with (50%) and without depression on cognitive tasks and showed that depression per se did not influence performance. Finally, the results demonstrate that interactions between apathy and motor disturbance have a significant effect on cognitive impairment in HD. DISCUSSION: The presence of apathy is associated with more severe deficits of attention, executive function and episodic memory in early HD patients. Furthermore, the findings suggest that depression has little or no effect on cognitive deficits. Finally, apathy increased in parallel with both motor and cognitive dysfunction.

Striatal neural grafting improves cortical metabolism in Huntington's disease patients.

Huntington's disease is a hereditary disease in which degeneration of neurons in the striatum leads to motor and cognitive deficits. Foetal striatal allografts reverse these deficits in phenotypic models of Huntington's disease developed in primates. A recent open-label pilot study has shown some clinical improvement or stabilization in three out of five Huntington's disease patients who received bilateral striatal grafts of foetal neurons. We show here that the clinical changes in these three patients were associated with a reduction of the striatal and cortical hypometabolism, demonstrating that grafts were able to restore the function of striato-cortical loops. Conversely, in the two patients not improved by the grafts, striatal and cortical hypometabolism progressed over the 2-year follow-up. Finally, detailed anatomical-functional analysis of the grafted striata, enabled by the 3D fusion of MRI and metabolic images, revealed considerable heterogeneity in the anatomic and metabolic profiles of grafted tissue, both within and between Huntington's disease patients. Our results demonstrate the usefulness of PET measurements of brain glucose metabolism in understanding the effects of foetal grafts in patients with Huntington's disease.