Measuring cognitive impairment and monitoring cognitive decline in Huntington's disease: a comparison of assessment instruments.

BACKGROUND: Progressive cognitive decline is an inevitable feature of Huntington's disease (HD) but specific criteria and instruments are still insufficiently developed to reliably classify patients into categories of cognitive severity and to monitor the progression of cognitive impairment. METHODS: We collected data from a cohort of 180 positive gene-carriers: 33 with premanifest HD and 147 with manifest HD. Using a specifically developed gold-standard for cognitive status we classified participants into those with normal cognition, those with mild cognitive impairment, and those with dementia. We administered the Parkinson's Disease-Cognitive Rating Scale (PD-CRS), the MMSE and the UHDRS cogscore at baseline, and at 6-month and 12-month follow-up visits. Cutoff scores discriminating between the three cognitive categories were calculated for each instrument. For each cognitive group and instrument we addressed cognitive progression, sensitivity to change, and the minimally clinical important difference corresponding to conversion from one category to another. RESULTS: The PD-CRS cutoff scores for MCI and dementia showed excellent sensitivity and specificity ratios that were not achieved with the other instruments. Throughout follow-up, in all cognitive groups, PD-CRS captured the rate of conversion from one cognitive category to another and also the different patterns in terms of cognitive trajectories. CONCLUSION: The PD-CRS is a valid and reliable instrument to capture MCI and dementia syndromes in HD. It captures the different trajectories of cognitive progression as a function of cognitive status and shows sensitivity to change in MCI and dementia.

Assessment of C Fibers Evoked Potentials in Healthy Subjects by Nd : YAP Laser.

Introduction: Although laser stimuli activate both Ad- and C-fibres, the corresponding laser evoked potentials (LEPs) remain restricted to the Ad-fibers input, while the C-fibers related potential is hardly detectable. Aims: To evaluate multichannel ultralate LEPs (U-LEPs) by using Nd : Yap laser pulses in healthy volunteers to stimulation of face and lower and upper limbs, in order to estimate the reliability of C-LEPs elicited from both trigeminal and somatic sites. Methods: Twenty healthy volunteers participated in two stimulation sessions to record Aδ-LEPs and C-LEPs. We used a Nd : YAP Laser and 62 EEG recording electrodes. Stimuli parameters were set to activate either small myelinated (Aδ), eliciting purely warmth sensations, or unmyelinated (C) afferents, and eliciting pinprick sensations. Results: At the trigeminal level, we obtained a negative-positive complex in a time interval compatible with the C fibers activation. In the somatic districts, the averaged responses consisted of an earlier negative-positive complex, followed by a later one. Single trials analysis of U-LEPs showed a maximal positive peak in a time interval in the range of C fibers. Topographical analysis of U-LEPs resembled that of LEPs. All subjects exhibited readable U-LEPs in at least 2 stimulated sites. Discussion. A purely warmth sensation seems to correspond to Aδ and C-fibers coactivation, at least in the somatic districts. While the related cortical waves seem hardly readable, their total absence could be a sign of systemic involvement of warm related C-fibers in specific clinical conditions.

Observational pain assessment in older persons with dementia in four countries: Observer agreement of items and factor structure of the Pain Assessment in Impaired Cognition.

BACKGROUND: Recognition of pain in people with dementia is challenging. Observational scales have been developed, but there is a need to harmonize and improve the assessment process. In EU initiative COST-Action TD1005, 36 promising items were selected from existing scales to be tested further. We aimed to study the observer agreement of each item, and to analyse the factor structure of the complete set. METHODS: One hundred and ninety older persons with dementia were recruited in four different countries (Italy, Serbia, Spain and The Netherlands) from different types of healthcare facilities. Patients represented a convenience sample, with no pre-selection on presence of (suspected) pain. The Pain Assessment in Impaired Cognition (PAIC, research version) item pool includes facial expressions of pain (15 items), body movements (10 items) and vocalizations (11 items). Participants were observed by health professionals in two situations, at rest and during movement. Intrarater and interrater reliability was analysed by percentage agreement. The factor structure was examined with principal component analysis with orthogonal rotation. RESULTS: Health professionals performed observations in 40-57 patients in each country. Intrarater and interrater agreement was generally high (≥70%). However, for some facial expression items, agreement was sometimes below 70%. Factor analyses showed a six-component solution, which were named as follows: Vocal pain expression, Face anatomical descriptors, Protective body movements, Vocal defence, Tension and Lack of affect. CONCLUSIONS: Observation of PAIC items can be done reliably in healthcare settings. Observer agreement is quite promising already without extensive training. SIGNIFICANCE: In this international project, promising items from existing observational pain scales were identified and evaluated regarding their reliability as an alternative to pain self-report in people with dementia. Analysis on factor structure helped to understand the character of the items. Health professionals from four countries using four different European languages were able to rate items reliably. The results contributed to an informed reduction of items for a clinical observer scale (Pain Assessment in Impaired Cognition scale with 15 items: PAIC15).

The Pain Assessment in Impaired Cognition scale (PAIC15): A multidisciplinary and international approach to develop and test a meta-tool for pain assessment in impaired cognition, especially dementia.

BACKGROUND: Over the last decades, a considerable number of observational scales have been developed to assess pain in persons with dementia. The time seems ripe now to build on the knowledge and expertize implemented in these scales to form an improved, "best-of" meta-tool. The EU-COST initiative "Pain in impaired cognition, especially dementia" aimed to do this by selecting items out of existing observational scales and critically re-assessing their suitability to detect pain in dementia. This paper reports on the final phase of this collaborative task. METHODS: Items from existing observational pain scales were tested for "frequency of occurrence (item difficulty)," "reliability" and "validity." This psychometric testing was carried out in eight countries, in different healthcare settings, and included clinical as well as experimental pain conditions. RESULTS: Across all studies, 587 persons with dementia, 27 individuals with intellectual disability, 12 Huntington's disease patients and 59 cognitively healthy controls were observed during rest and movement situations or while receiving experimental pressure pain, respectively. The psychometric outcomes for each item across the different studies were evaluated within an international and multidisciplinary team of experts and led a final selection of 15 items (5x facial expressions, 5x body movements, 5x vocalizations). CONCLUSIONS: The final list of 15 observational items have demonstrated psychometric quality and clinical usefulness both in their former scales and in the present international evaluation; accordingly, they qualified twice to form a new internationally agreed-on meta-tool for Pain Assessment in Impaired Cognition, the PAIC-15 scale. SIGNIFICANCE: Using a meta-tool approach by building on previous observational pain assessment scales and putting the items of these scales through rigorous empirical testing (using experimental as well as clinical pain studies in several European countries), we were able to identify the best items for pain assessment in individuals with impaired cognition. These selected items form the novel PAIC15 scale (pain assessment in impaired cognition, 15 items).

Promoting adaptive behavior in persons with acquired brain injury, extensive motor and communication disabilities, and consciousness disorders.

These two studies extended the evidence on the use of technology-based intervention packages to promote adaptive behavior in persons with acquired brain injury and multiple disabilities. Study I involved five participants in a minimally conscious state who were provided with intervention packages based on specific arrangements of optic, tilt, or pressure microswitches (linked to preferred environmental stimuli) and eyelid, toe and finger responses. Study II involved three participants who were emerging from a minimally conscious state and were provided with intervention packages based on computer presentations of stimulus options (i.e., preferred stimuli, functional caregiver's procedures, and non-preferred stimuli) and pressure microswitches to choose among them. Intervention data of Study I showed that the participants acquired relatively high levels of microswitch responding (thus engaging widely with preferred environmental stimuli) and kept that responding consistent except for one case. Intervention data of Study II showed that the participants were active in choosing among preferred stimuli and positive caregivers' procedures, but generally abstained from non-preferred stimuli. The results were discussed in terms of the successful use of fairly new/infrequent microswitch-response arrangements (Study I) and the profitable inclusion of functional caregiver's procedures among the options available to choice (Study II).

A learning assessment procedure as a test supplement for monitoring progress with two post-coma persons with a diagnosis of vegetative state.

OBJECTIVE: Evaluating a learning assessment procedure for monitoring progress with two post-coma adults with a diagnosis of vegetative state. METHOD: ABABCBCB and ABABCB designs were used for the two participants, with A representing baseline, B intervention and C control conditions. Participants' activation of an optic microswitch by eyelid closure produced stimulation during B phases. RESULTS: One participant increased responding during B phases and decreased it during the C condition, suggesting a non-reflective minimal level of consciousness. She showed P300 and mismatch negativity responses and scored at the vegetative level on the Coma Recovery Scale-Revised (CRS-R). The other participant increased responding during the initial B phases without decline during the first (viable) part of the C condition, suggesting a pre-conscious level. He showed indistinct P300 and mismatch negativity responses and vegetative-level scores on the CRS-R. CONCLUSION: Learning data seemed reconcilable with neurophysiological measures and more positive than CRS-R scores.

A technology-assisted learning setup as assessment supplement for three persons with a diagnosis of post-coma vegetative state and pervasive motor impairment.

Post-coma persons in an apparent condition of vegetative state and pervasive motor impairment pose serious problems in terms of assessment and intervention options. A technology-based learning assessment procedure might serve for them as a diagnostic supplement with possible implications for rehabilitation intervention. The learning assessment procedure adopted in this study relied on hand-closure and eye-blinking responses and on microswitch technology to detect such responses and to present stimuli. Three participants were involved in the study. The technology consisted of a touch/pressure sensor fixed on the hand or an optic sensor mounted on an eyeglasses' frame, which were combined with a control system linked to stimulus sources. The study adopted an ABABCB sequence, in which A represented baseline periods, B intervention periods with stimuli contingent on the responses, and C a control condition with stimuli presented non-contingently. Data showed that the level of responding during the B phases was significantly higher than the levels observed during the A phases as well as the C phase for two of the three participants (i.e., indicating clear signs of learning by them). Learning might be deemed to represent basic levels of knowledge/consciousness. Thus, detecting signs of learning might help one revise a previous diagnosis of vegetative state with wide implications for rehabilitation perspectives.

A learning assessment procedure to re-evaluate three persons with a diagnosis of post-coma vegetative state and pervasive motor impairment.

PRIMARY OBJECTIVE: Detecting signs of learning in persons with a diagnosis of post-coma vegetative state and profound motor disabilities could modify their diagnostic label and provide new hopes. In this study, three adults with such a diagnosis were exposed to learning assessment to search for those signs. PROCEDURE AND DESIGN: The assessment procedure relied on participants' eye-blinking responses and microswitch-based technology. The technology consisted of an electronically regulated optic microswitch mounted on an eyeglasses' frame that the participants wore during the study and an electronic control system connected to stimulus sources. Each participant followed an ABABCB design, in which A represented baseline periods, B intervention periods with stimuli contingent on the responses and C a control condition with stimuli presented non-contingently. MAIN OUTCOMES AND RESULTS: The level of responding during the B phases was significantly higher than the levels observed during the A phases as well as the C phase for all participants (i.e. indicating clear signs of learning by them). CONCLUSIONS: These findings may have important implications for (a) changing the participants' diagnostic label and offering them new programme opportunities and (b) including learning assessment within the evaluation package used for persons with post-coma profound multiple disabilities.

Evaluation of technology-assisted learning setups for undertaking assessment and providing intervention to persons with a diagnosis of vegetative state.

OBJECTIVE: To evaluate the viability of technology-assisted learning setups for undertaking assessment and providing intervention to persons in vegetative state. METHOD: Study I investigated whether three persons with a diagnosis of vegetative state could associate eye blinking or hand closure responses with contingent, positive stimulation, thus increasing their frequencies (showing signs of learning). Study II extended the learning process (introducing a new response and new stimuli) for one of the participants of Study I. RESULTS: Two of the participants of Study I succeeded in increasing their responses, indicating signs of learning. Study II showed that the participant (one of the two succeeding in Study I) acquired a new response to access new stimuli and could alternate this response with the one acquired in Study I. CONCLUSION: Learning might represent a basic level of knowledge and consciousness. Detecting signs of learning might help modify a previous diagnosis of vegetative state and support intervention/rehabilitation efforts.