Olivier Deschaux

Comparing three morningness scales: Age and gender effects, structure and cut-off criteria

OBJECTIVE To add to the validity of the French version of the Composite Scale of Morningness (CSM) by comparing its structure with that of the Morningness-Eveningness Questionnaire (MEQ), the most widely used scale to measure circadian typology. Second, to compare the cut-off criteria used to transform the continuous scores into categorical chronotypes. Third, to further test the effects of age and gender on morningness scores. The rMEQ, a shortened version of the MEQ, is also considered. METHODS Four hundred and fifty-six students served as volunteer subjects and filled the CSM and the MEQ. RESULTS There was no effect of gender, and the CSM and MEQ scores correlated above (+) 0.90 in both genders. Regarding age, morningness was stable before age 35 and increased afterwards. We replicated the three-factor structure of the CSM previously reported in five different cultures. The MEQ is longer and counted a fourth factor while the first three factors were quite identical to those extracted from the CSM. This comparative study emphasizes the recurrent problem of cut-off scores: the available values for both instruments result in a very poor concordance of chronotypes. CONCLUSIONS Belonging to the evening-type is regarded as a risk factor for sleep disorders and its positive predictive value should be correctly assessed. Hence, normative scores standardized in such a way they reflect the effects of age, gender and culture are needed for the total score and the factor scores. To this extent, T-scores (with a mean of 50 and standard deviation of 10) would be suitable, and normative tables for French subjects (N = 1598) are given as supplemental data.

Decreased Daytime Motor Activity Associated With Apathy in Alzheimer Disease: An Actigraphic Study

OBJECTIVE Across all stages of Alzheimer disease (AD), apathy is the most common neuropsychiatric symptom. Studies using the Neuropsychiatric Inventory (NPI) have found that apathy is present in up to 70% of individuals with Alzheimer disease. One of the main difficulties in assessing apathy and other neuropsychiatric symptoms is the absence of reliable, objective measures. Motor activity assessment using ambulatory actigraphy could provide an indirect, objective evaluation of apathy. The aim of our study was to assess the relationship between apathy and daytime motor activity in AD, using ambulatory actigraphy. METHODS One hundred seven AD outpatients wore a wrist actigraph (Motionlogger) during seven consecutive 24-hour periods to evaluate motor activity. Participants were divided into two subgroups according to their apathy subscores on the NPI: individuals with apathy (NPI-apathy subscores >4) and those without. Daytime mean motor activity scores were compared between the two subgroups. RESULTS Individuals with AD who had symptoms of apathy (n = 43; age = 79 ± 4.7 years; Mini-Mental State Examination = 20.9 ± 4.8) had significantly lower daytime mean motor activity than AD patients without apathy (n = 64; age = 76.3 ± 7.7; Mini-Mental State Examination = 21.5 ± 4.7), while nighttime mean motor activity did not significantly differ between the two subgroups. CONCLUSIONS Ambulatory actigraphy could be added to currently used questionnaires as a simple, objective technique for assessing apathy in the routine assessment of AD patients.

Re-emergence of extinguished auditory-cued conditioned fear following a sub-conditioning procedure: Effects of hippocampal and prefrontal tetanic stimulations

Post-extinction exposure of rats to a sub-conditioning procedure can evoke conditioned fear, which may correspond to fear return and/or fear learning potentiation. The aim of the present study was to clarify this issue and examine the effects of tetanic stimulation of the hippocampus (HPC) and medial prefrontal cortex (mPFC), two brain regions implicated in post-extinction modulation of conditioned fear. Rats were initially submitted to five tone-shock pairings with either a 0.7-mA or 0.1-mA shock. Tone-evoked freezing was observed only with the higher shock intensity, indicating that the 0.1-mA shock corresponded to a sub-conditioning procedure. All conditioned rats underwent fear extinction with 20 tone-alone trials. When retrained with the sub-conditioning procedure, they displayed again tone-evoked freezing, except when the initial tone was unpaired or a new tone was paired with the 0.1-mA shock, demonstrating fear return rather than fear learning potentiation. We also found that HPC and mPFC tetanic stimulations, applied 24h after the sub-conditioning procedure, similarly reduced this fear return. However, mPFC inactivation abolished temporary HPC tetanus effect, whereas HPC inactivation did not interfere with mPFC tetanus effect. These data confirm our previous findings and reveal the nature of HPC-mPFC interactions in post-extinction modulation of conditioned fear.

Low-frequency stimulation of the hippocampus following fear extinction impairs both restoration of rapid eye movement sleep and retrieval of extinction memory.

Post-learning rapid eye movement (REM) sleep deprivation has often been shown to impair hippocampal functioning, which results in deficit in retrieval of some types of memory. However, it remains to be determined whether post-learning alteration of hippocampal functioning affects, in turn, REM sleep. Recent studies have shown that both post-extinction REM sleep deprivation and post-extinction application of hippocampal low-frequency stimulation (LFS) impair memory of fear extinction, indicating possible bidirectional interactions between hippocampal functioning and REM sleep. To analyze the potential effect of post-extinction alteration of hippocampal functioning on REM sleep, rats were implanted with stimulating electrodes in the dorsal hippocampus for post-extinction LFS. Sleep was recorded before (two sessions, 1 day apart) and after conditioning (five tone and eyelid-shock pairings), and following extinction training (25 tone-alone presentations) for 6 h per session. Fear conditioning reduced time spent in REM sleep, which was restored with fear extinction. Hippocampal LFS, applied immediately following extinction training, abolished the restorative effect of fear extinction on REM sleep and impaired extinction retrieval. These data extend previous findings and suggest bidirectional interactions between hippocampal functioning and REM sleep for successful extinction retrieval.

Apathy assessment using 7-days ambulatory actigraphy in Alzheimer's disease

cognitive impairment, have a design optimized for cognitively impaired users, be appropriate in diverse cultural settings, and suited for web-based self-administration. Computerized batteries already in existence have not been designed to cover all features. This study describes the design process of Cognitive Testing on Computer (C-TOC), an innovative tool under development that is aimed at improving diagnostic service delivery in cognitive impairment and dementia. Methods: The prototype C-TOC-version1 (CTOCv1) was created with reference to neuropsychological findings on Mild Cognitive Impairment, Alzheimer Disease (AD), and on the differentiation between AD and non-AD dementias. C-TOCv1 was evaluated and revised by a panel of clinicians with expertise in cognitive disorders. In ongoing studies, C-TOCv1 is further developed in a 3-cycle iterative design, with input from end users and from representatives of major ethnocultural groups. Individuals referred to a dementia clinic are consulted on the face validity of the tests and the usability of the computer interface. Representatives from ethnocultural groups are consulted on the validity of the tests within their own communities. Results: C-TOCv1 has been created as a mock-up of an entirely self-administered computerized test battery, which requires only use of the mouse. Test stimuli are presented visually. The aimed-for time to complete C-TOC is 30 minutes. C-TOCv1 covers the domains of episodic memory, orientation, attention, psychomotor speed, language, problem-solving and visuo-spatial construction. There are 12 tasks including Cued memory, Paired associates, Temporal orientation, Symbol digits, Trail making, Arithmetics, Sentence production and comprehension, Similarities, Pattern construction, Pattern completion, and Go-No-Go. Conclusions: CTOC is a tool developed iteratively with input from its end users and including ethnocultural considerations. By design C-TOC should have broad applicability, both for the office and the web. The uptake of C-TOC in dementia/ memory clinics could in the future reduce waiting times, optimize resource utilization, guide follow-up and help to provide diagnostic services for those living in remote locations.