Geometry of color perception. Part 2: perceived colors from real quantum states and Hering's rebit.

Inspired by the pioneer work of H.L. Resnikoff, which is described in full detail in the first part of this two-part paper, we give a quantum description of the space [Formula: see text] of perceived colors. We show that [Formula: see text] is the effect space of a rebit, a real quantum qubit, whose state space is isometric to Klein's hyperbolic disk. This chromatic state space of perceived colors can be represented as a Bloch disk of real dimension 2 that coincides with Hering's disk given by the color opponency mechanism. Attributes of perceived colors, hue and saturation, are defined in terms of Von Neumann entropy.

Donepezil provides greater benefits in mild compared to moderate Alzheimer's disease: implications for early diagnosis and treatment.

We assessed the cognitive and functional outcomes of donepezil treatment in mild versus moderate Alzheimer's disease (AD) patients. We performed a 6-month prospective, observational, multicenter study of the progression of cognitive and functionality abilities in a large sample patients with AD who initiated treatment with donepezil in monotherapy. According to baseline mini mental state examination (MMSE), patients were divided in two groups: mild AD (MMSE ≥ 21) and moderate AD (MMSE <21). Patients were evaluated with the memory alteration test (M@T) and the Alzheimer's disease functional assessment and change scale (ADFACS) at baseline and at 6 months. A total of 403 patients finished the study (mild AD=152; moderate AD=251). The MMSE total score and M@T score remained stable at 6 months in the whole sample, with MMSE memory domain and M@T free and cued recall domains improving significantly from baseline. Total ADFACS, instrumental (IADL) and basic activities of daily living (BADL) got significantly worse, with the worsening being significantly greater in the moderate AD group. Significant differences between the groups favoring mild AD were observed for MMSE memory, orientation and language domains, M@T temporal orientation and semantic memory domains, and for IADL. We concluded that in AD patients on donepezil, cognition remains stable at 6 months. The beneficial effect of donepezil treatment, in terms of cognition and functionality, is greater for mild than for moderate AD.

Early occupational therapy programme increases hand grip strength at 3 months: results from a randomised, blind, controlled study in early rheumatoid arthritis.

AIM: The goal of occupational therapy (OT) is to facilitate adjustments to lifestyle and to prevent function loss. This study evaluated the effects of an early OT programme in early rheumatoid arthritis (RA). METHODS: We conducted a randomised, blind, controlled trial enrolling 60 patients with early RA, divided into 2 groups. At baseline, group 1 received the full information programme and group 2 received no information. In an extension phase, patients in group 2 received the full information programme at 3 months and were assessed at 6 months. The main outcomes were grip strength of hands (as objective assessment) and Health Assessment Questionnaire (HAQ) score (as subjective assessment). RESULTS: At 3 months, grip strength of the dominant and non-dominant hands increased more in group 1 than in group 2 (p = 0.021 and 0.047 respectively). HAQ score decreased more in group 1 than in group 2 (p<0.001). In the extension phase, changes in grip strength and HAQ score in group 2 were similar to those seen in group 1 between baseline and 3 months. CONCLUSIONS: This study comparing two schedules of OT programme showed that an early extended information programme improved hand function in patients with early RA.

Prevalencia y comorbilidad de síntomas neuropsiquiátricos en la enfermedad de Alzheimer / Prevalence and comorbidity of neuropsychiatric symptoms in Alzheimer's disease

Introducción. Se describe la frecuencia y gravedad de los síntomas conductuales y psicológicos (SCP) en un grupo de125 pacientes diagnosticados con enfermedad de Alzheimer(EA) siguiendo criterios diagnósticos DSM-IV-TR y NINCDSADRDA. Metodología. La evaluación de los SCP se realizó mediante el Neuropsychiatric Inventory (NPI; Cummings et al., 1994). Se recogieron los datos sociodemográficos y antecedentes personales de los pacientes y se estableció el estadio de la demencia mediante la Global Deterioration Scale (GDS; Reisberg, 1982). Resultados. Un total de 122 pacientes (98%) presentaron SCP, con una media de cinco síntomas por paciente. La frecuencia de su presentación fue la siguiente: apatía (75%), irritabilidad (66%), depresión (60%), agitación (55%), ansiedad (54%), actividad motora aberrante (47%), delirios (38%), alteraciones del sueño (36 %), desinhibición (29 %), alteraciones del apetito (28%), alucinaciones (20%) y euforia (4%). Conclusiones. Estos resultados demuestran la alta incidencia de los SCP en los pacientes con EA y muestran la necesidad e importancia de tratar adecuadamente estas alteraciones (AU)

Introduction. The objective of this study is to describe the frequency and severity of behavioral and psychological symptoms (BPS) in a group of 125 patients diagnosed of Alzheimer’s disease (AD) (DSM-IV-TR and NINCDSADRDA criteria). Methods. The evaluation of the BPS was carried out using the Neuropsychiatric Inventory (NPI; Cummings et al., 1994). The sociodemographic and personal background data of the patients were gathered and the dementia stage was established with the Global Deterioration Scale (GDS Reisberg, 1982). Results. A total of 122 patients (98%) presented BPS, with an average of five symptoms per patient. Frequency of presentation was the following: apathy (75%), irritability (66 %), depression (60 %), agitation (55 %), anxiety (54 %), aberrant motor activity (47 %), delirium (38 %), sleeping disorders (36%), disinhibition (29%), eating disorders (28%), hallucinations (20%) and euphoria (4%). Conclusions. These results show the high incidence of BPS in AD patients and point to the necessity and importance of treating these disorders appropriately (AU)

[Prevalence and comorbidity of neuropsychiatric symptoms in Alzheimer's disease]. / Prevalencia y comorbilidad de síntomas neuropsiquiátricos en la enfermedadde Alzheimer.

INTRODUCTION: The objective of this study is to describe the frequency and severity of behavioral and psychological symptoms (BPS) in a group of 125 patients diagnosed of Alzheimer's disease (AD) (DSM-IV-TR and NINCDSADRDA criteria). METHODS: The evaluation of the BPS was carried out using the Neuropsychiatric Inventory (NPI; Cummings et al., 1994). The sociodemographic and personal background data of the patients were gathered and the dementia stage was established with the Global Deterioration Scale (GDS Reisberg, 1982). RESULTS: A total of 122 patients (98%) presented BPS, with an average of five symptoms per patient. Frequency of presentation was the following: apathy (75%), irritability (66%), depression (60%), agitation (55%), anxiety (54%), aberrant motor activity (47%), delirium (38%), sleeping disorders (36%), disinhibition (29%), eating disorders (28%), hallucinations (20%) and euphoria (4%). CONCLUSIONS: These results show the high incidence of BPS in AD patients and point to the necessity and importance of treating these disorders appropriately.

Influences of the phosphatidylcholine transfer protein gene variants on the LDL peak particle size.

BACKGROUND: The small, dense LDL phenotype is associated with an increased cardiovascular disease risk. A genome-wide scan performed on 236 nuclear families of the Quebec Family Study (QFS) revealed a quantitative trait locus (QTL) affecting LDL peak particle size (LDL-PPD) and density on the 17q21 region. This region contains the phosphatidylcholine transfer protein gene (PCTP). In the liver, phosphatidylcholine transfer protein binds specifically phosphatidylcholine suggesting a role for this protein in the formation of HDL and possibly VLDL phospholipid membranes. OBJECTIVES: To test the association between two coding polymorphisms (c.29A>C (Glu10Ala) and c.188G>A (Cys63Tyr)) in PCTP gene and the LDL-PPD. METHODS: LDL-PPD was measured by non-denaturating 2-16% polyacrylamide gradient gel electrophoresis on 623 QFS subjects. RESULTS: After adjustment for age and sex, carriers of the c.29C allele showed larger LDL-PPD than A/A homozygotes (p<0.05). These results remained significant when LDL-PPD was further adjusted for the effects of BMI and triglyceride levels (p<0.04). We also observed a three-fold lower risk of having the small (LDL-PPD <256A), dense LDL phenotype in subjects carrying the c.29C allele, when compared to A/A homozygotes (OR=0.35 (95% CI: 0.14-0.91; p=0.03)). CONCLUSION: PCTP gene variants are associated with LDL-PPD.

A randomized, placebo-controlled study of donepezil in poststroke aphasia.

We studied 26 patients in a randomized, placebo-controlled, double-blind parallel trial to evaluate the efficacy and safety of donepezil in chronic poststroke aphasia. Donepezil (10 mg/day) improved aphasia severity at endpoint (week 16) relative to placebo (p = 0.037).

Quantitative and qualitative hydrologic balance for a suburban watershed with a separate sewer system (Nantes, France).

A qualitative and quantitative budget at the outlet of the storm-water runoff system of a small suburban watershed is presented together with some data regarding waste-water. 445,000 m3 (34% of the rain-water volume) were drained by the storm-water runoff system and 40,879 m3 by the waste-water system from September 2002 to March 2004. Storm-water runoff is generally not heavily polluted with regard to trace metals but concentrations occasionally exceed the standards for surface water of good quality. On the contrary, pesticides (diuron and glyphosate) have very high concentrations especially in spring and autumn when their use is maximum. As the St Joseph storm-water runoff is finally discharged into the Erdre River, measures to reduce the use of these pollutants should be considered.

Effects of repetitive transcranial magnetic stimulation on memory subtypes: a controlled study.

Repetitive transcranial magnetic stimulation (rTMS) of human cortex may disrupt or facilitate cortical activity. The aim of the present study was to investigate the consequences of rTMS applied over different cortical areas during various memory tasks, measuring immediate, working and episodic verbal memory. The study was performed in 16 right-handed healthy men. A double-blind, cross-over, within-subject repeated measures design was used. There were five rTMS conditions: baseline without stimulation, high frequency (HF) rTMS over right and left dorsolateral prefrontal cortex (DLPFC) and over right cerebellum, and low frequency (LF) parameters over left DLPFC. Digits forwards and backwards and letter-number sequencing of the Wechsler Adults Intelligence Scale (WAIS) were used to assess immediate and working verbal memory, and logical memory of the Rivermead Behavioural Memory Test was used to assess episodic memory encoding. An analysis of variance (ANOVA) for repeated measures in the scores of each memory task according to rTMS conditions was used. Significantly lower scores in the number of memory units of the episodic memory task were observed when rTMS high frequency parameters were applied over left DLPFC (P=0.009). No significant differences were found in the other memory subtype tasks analysed during the different rTMS conditions. These findings provide evidence for the significant role of the left DLPFC in episodic verbal memory processes.

[ERPs (N200, P300 and CNV) in alcoholics: relapse risk assessment]. / Les potentiels évoqués cognitifs chez les patients alcooliques: évaluation du risque de rechute.

The cognitive event-related potentials were studied in a group of 55 alcoholic patients, paired in age and sex with a group of 18 control subjects, using a protocol oddball (visual and auditory) and a protocol VCN Go/Nogo. The N200 obtained using an auditory oddball paradigm had lower amplitude in alcoholics than in controls. A significant amplitude decrease of visual P300 was also observed in alcoholic male subjects. There was however no difference in auditory P300 between alcoholics and control subjects. Using a Go/Nogo paradigm, a significant difference on the final part of the VCN appears between alcoholic and pilot subjects. In addition, the longitudinal follow-up of the same alcoholic patients showed an electrophysiological profile that allowed dividing them into two different groups. On the initial recording (17 days after weaning), the auditory oddball P300 amplitude was significantly higher at Cz and Pz among patients who relapsed during the 3 months follow-up. The same effect appeared on the CNV protocol, where the amplitude of P300 was higher in patients who subsequently relapsed than for those who remained abstinent. Cognitive ERPs may be clinically useful to improve the prediction of risk of relapse among alcoholic patients.

[Interest of neurophysiological exploration in clinical psychiatry]. / Intérêt de l'exploration neurophysiologique en psychiatrie clinique.

Cerebral functional exploration using Event related potentials (ERPs) is greatly relevant in clinical psychiatry. Although ERP usefulness as a diagnostic tool is limited due to the complexity of psychiatric diagnosis, which raises theoretical, methodological and ethical problems that cannot be resolved by neurobiological methods, ERP offers relevant information in 3 different topics: the choice of psychotropes in pharmacotherapy; the description and understanding of cognitive processes; the psychotherapeutic relation. 1) Converging arguments from experimental studies support the hypothesis that the amplitude of P300 and CNV as well as the loudness dependence of the auditory N1/P2 response (LDAEP) are regulated by central catecholaminergic and serotoninergic neurotransmission. These systems also are the target of several psychotropes, and therefore the neurophysiological assessment may bring reliable indicators to predict favourable response to psychotropes and drug intolerance. 2) Moreover the assessment of Reaction Times and P300 and VCN parameters, jointly recorded in a single investigation, brings information about the self-organization and self-regulation of cerebral functioning, and might help the clinicians to understand the functional meaning of attentional disorders in Psychiatry. 3) Finally, the discussion of the neurophysiological results with the patient, in comparing objective and subjective data, might help him to better understand his/her difficulties and to modify his/her subjective experience of the disease.

[How are personal child health records completed? A multicentric evaluation study]. / Le carnet de santé de l'enfant est-il informatif? Evaluation dans différentes structures de prévention et de soins.

OBJECTIVE: To evaluate the completeness of personal child health record in France. PATIENTS AND METHODS: Cross-sectional multicentric study, based on child health records analysed and parents' interviews; 1685 children were included: 863 infants aged from 12 to 18 month and 822 children aged from three and a half to four and a half years. RESULTS: One Apgar score was recorded in 96% of cases; the sitting position's acquisition was registered in 91%; the age of walk in 81%. Growth curves were plotted in 64% of cases for weight and in 62% for height in infant's records and 22% of cases for both in older children's records. Ten per cent of the last visit to a physician were not recorded in infants health records, 19% in those of children; as well an hospitalisation for respectively 1,5% and 3,3% and a performed operation for 1,8% and 5,1% respectively. Immunization batches were exhaustively indicated in 68% and 50% of the records. CONCLUSION: Many important data for medical follow-up are missing in the child health records, especially for the oldest children. Physicians and parents should be incited to a better use of the personal record.

[Johanson-Blizzard syndrome: a case report]. / Syndrome de Johanson-Blizzard: à propos d'un cas.

UNLABELLED: The Johanson-Blizzard syndrome is a rare autosomal recessive syndrome. This syndrome includes congenital aplasia of the cutis, aplasia of the alae nasi, bilateral hearing loss, dental malformations and pancreatic insufficiency. CASE REPORT: We report a sporadic case male infant from nonconsanguineous parents. He presented aplasia of the cutis and high anorectal malformation, associated with exocrine pancreatic insufficiency. A colostomy was performed at birth and anorectal atresia was corrected surgically at two months. Exocrine pancreatic insufficiency required immediate enzyme supplementation.

Mania following deep brain stimulation for Parkinson's disease.

Three patients with PD developed manic behavior after bilateral implantation of electrodes for deep-brain stimulation (DBS). Common to all three patients were manic symptoms unremitting after levodopa reduction or stimulation "off," lower electrodes positioning caudal to the subthalamic nucleus area, postoperative DBS with the lower contacts (0) of the quadripolar electrodes, and resolution of the manic episodes coinciding with stimulation through higher contacts.

[Study of the stress response: role of anxiety, cortisol and DHEAs]. / Etude de la réponse de stress: rôle de l'anxiété, du cortisol et du DHEAs.

AIM OF THE STUDY: Several studies have exhibited the psychological processes that are implied in the stress response and have shown, according to Selye's research, the participation of the hypothalamic-pituitary-adrenal axis and the major role of cortisol. The possible action of another adrenal steroïd, dehydroepiandrosterone (DHEA), is increasingly documented. The beneficial effect of the latter and his antistress role would be related to an antagonistic action to that of cortisol. The aim of our study was, first to assess biological and psychological aspects of the stress response, then to define the relationships that exist between these two processes. POPULATION AND METHODOLOGY: 40 subjects (21 women) aged 42 +/- 12 years, who consulted within a clinic of stress (CITES Prevert, Liege, Belgium) were studied. They all felt stressed but, according to DSM IV, were without mental disorders and drug free when examined. Subjects were asked to accomplish simple cognitive tasks: 1 - to distinguish two different auditory stimulations. The first one was a high-pitched sound of 1 470 Hz, which was presented unfrequently (20%). The second one, a low frequency tone of 800 Hz, was presented more frequently (80%). The interval between both stimuli was 1 s. The subject had to press a button when the rare stimulus was recognized. 2 - to extinguish a light after a warning tone of 64 dB, 50 ms and 1 000 Hz. The light, which followed one second later the tone, consisted of a series of flashes of 18 c/s that the subject had to stop by pressing a button. The purpose of this second procedure was that the subject was warned and had to prepare and anticipate the most rapid response. After that, subjects were submitted to self-evaluation psychological tests. The impact of psychosocial factors was assessed by Amiel-Lebigre life events questionnaire. Personality features and emotional response (state anxiety, related to experimental situation) were assessed by Spielberger inventory (STAI: State and Trait Anxiety Inventory). Psychological tests are practised immediately after experimental situation. Cortisol and DHEAs (dehydroepiandrosterone sulfate) were measured in blood samples taken before (t1) and after (t2) the experimental test. Cortisol was measured by radio-immunology and expressed as ng/ml of plasma. DHEAs was measured by radio-immunoassay and expressed as g/liter of plasma. RESULTS AND DISCUSSION: The majority of subjects displayed high scores of trait anxiety (37 subjects had a score>42) and life events impact (35 subjects had a score>200). These data confirmed that the subjects were fragile and were obviously stressed. In response to the cognitive tasks, that constituted for each subject a new event with which it was necessary to cope, 25 subjects exhibited high level of state anxiety (score>42) and an increase of cortisol plasmatic concentrations occurred solely in 11 persons. Ten among them were in the group of subjects which displayed a score of state anxiety>42 (p=0,0223, Chi square). Base on these data three types of stress response were identified: 1 - the experimental situation was experienced without anxiety ( psychological silence ) and without any increase in cortisol level ( biological silence ). There was no stress and these subjects were, despite their vulnerability, close to a normal health state . 2 - high emotional reaction (high level of state anxiety) was observed. This response reveals a psychological vulnerability that can be considered as the expression of a consecutive psychological distress induced by a threatening experimental situation. There were no biological manifestations ( biological silence ). 3 - high state anxiety and increased plasma cortisol levels were observed. The corresponding subjects were obviously more vulnerable. CONCLUSION: These results allow us to propose that the emergence of state anxiety is the first stress response and the primary protest . Up to a certain level, a plateau level, anxiety remains stable. Then, nature of the stress response changes and takes a biological aspect. Increased of cortisol plasma levels, the secondary protest , is observed and gives evidence of an intensified and sustained stress response. Such a gradual phenomenon is particularly reported in elevated psychological distress which is associated with loss of control. It is important to note that identical scores of state anxiety (Mann Whitney test) were observed in anxious subjects with or without rise of plasma cortisol levels. DHEAs was also implied in the stress response. The enhancement of plasma levels of DHEAs were dependent on cortisol, as shown by the close correlation between both hormones (r=0,433, p=0,0033, Spearman test). The hypothesis of an antagonism between these two hormones is based on the fact that DHEAs opposes the action of cortisol and exerts a true anticortisol effect. This antagonism might be related to a competition in their synthesis and release by the adrenal gland. In the present case, high level of anxiety (state and trait) was associated with an increase of cortisol, while low level (of anxiety) was related to an exclusive rise of DHEAs. Intermediate anxious score was observed in subjects who showed increases of both cortisol and DHEAs (p=0,0225, Kruskall Wallis test). Furthermore, a close relationship (negative correlation: Spearman test), was observed between increases in DHEAS and scores of state anxiety (r=- 0,382, p=0,06) and trait anxiety (r=- 0,0097, p=0,527). This means that the worriness and the underlying anxious ruminations and negative anticipations, which characterize trait anxiety, were less important in subjects who increased plasma DHEAs levels. In addition, emotional tension and uneasiness, which accompanies state anxiety, were also less marked. There are no studies reporting a relation between DHEA(s) and state or trait anxiety. Nevertheless, many authors have proposed a beneficial action of DHEA on the feeling of well-being. This beneficial role could be related to a double action of DHEA: a direct effect provided by its transformation into sexual hormones, an indirect one mediated by its competition with cortisol, of which the synthesis and consequently the activity decrease.

Neuropsychiatric assessment of Gilles de la Tourette patients: comparative study with other hyperkinetic and hypokinetic movement disorders.

The role of the basal ganglia in conditions with co-occurring movement disorders and neuropsychiatric symptoms is not well known. It has been hypothesized that hyperkinesia -disinhibited behaviors and hypokinesia-inhibited behaviors result from an imbalance between the direct and indirect striatal output pathways, and that differential involvement of these pathways could account for the concurrent abnormalities in movement and behavior observed in these disorders. This study aimed to evaluate whether the pattern and the extent of the neuropsychiatric manifestations of patients with GTS, a hyperkinetic movement disorder of basal ganglia origin, differs from that of patients with other basal ganglia hyperkinetic (e.g., HD) or hypokinetic (e.g., PSP) movement disorders, and to determine whether patients with GTS show a greater frequency of hyperactive behaviors (e.g., agitation, irritability, euphoria, or anxiety) than PSP patients, and are comparable to patients with HD. The Neuropsychiatric Inventory (NPI), a scale with established validity and reliability, was administered to 26 patients with GTS (mean age, 30.2 +/- 2.2 years), and the results were compared with that of 29 patients with HD (mean age, 43.8 +/- 2 years) and 34 with PSP (mean +/- S.D. age, 66.6 +/- 1.2 years). There was no difference between the groups in the total NPI scores. However, there was a double dissociation in behaviors: patients with hyperkinetic disorders (HD and GTS) exhibited significantly more agitation, irritability, anxiety, euphoria, and hyperkinesia, whereas hypokinetic patients (PSP) exhibited more apathy. Patients with GTS showed greater scores than HD patients in all those scores differentiating HD and GTS from PSP patients (e.g., agitation, irritability, anxiety and euphoria), and were differentiated in a logistic regression analysis from both HD and PSP patients in having significantly more anxiety. We found that patients with GTS manifested predominantly hyperactive behaviors similar but more pronounced than those presented by patients with HD, while those with PSP manifested hypoactive behaviors. Based on our findings and the proposed models of basal ganglia dysfunction in these disorders, we suggest that the hyperactive behaviors in GTS are comparable to those observed in HD, being both secondary to an excitatory subcortical output through the medial and orbitofrontal cortical circuits, while in PSP the hypoactive behaviors are secondary to hypostimulation of these circuits. Abnormalities of other brain structures (e.g., amygdala, brainstem nuclei) may account for the significantly higher anxiety scores differentiating GTS from HD patients.

Effects of the FABP2 A54T mutation on triglyceride metabolism of viscerally obese men.

OBJECTIVE: Viscerally obese individuals are frequently characterized by a proatherogenic condition. A missense mutation (A54T) in the fatty acid binding protein type 2 (FABP2) gene has been associated with insulin resistance and obesity. This study examined the effect of this mutation on lipoprotein levels in viscerally obese hyperinsulinemic condition. RESEARCH METHODS AND PROCEDURES: A total of 217 men were assigned to one of two groups based on their FABP2 A54T polymorphism. RESULTS: The two genotypic groups showed no difference in either physiological characteristics or lipoprotein/lipid profile, before or after statistical adjustment for age. From this initial sample, 50 men accepted to have their postprandial lipid response assessed and 10 T54/A54 heterozygotes were then individually matched for visceral adipose tissue accumulation and fasting plasma triglyceride (TG) levels with 10 A54/A54 homozygotes. High-density lipoprotein (HDL)-TG levels were significantly increased in the fasting state as well as 4 hours after the test meal (p = 0.04 and p = 0.0008, respectively) in men bearing the A54T mutation. In addition, the area under the curve of postprandial HDL-TG levels was also significantly higher among T54/A54 heterozygotes than among A54/A54 homozygotes (p = 0.04). Interestingly, fasting TG concentrations in large TG-rich lipoproteins (large-TRL; S(f) > 400) were correlated with HDL-TG levels at 4 (r = 0.74, p = 0.01) and 8 hours (r = 0.73, p = 0.01) after the test meal in T54/A54 heterozygotes only. DISCUSSION: The FABP2 A54T missense mutation may contribute to the TG enrichment of HDL in the postprandial state that, in turn, may alter the risk of atherosclerotic vascular disease.

[Opioid addiction: P300 assessment in treatment by methadone substitution]. / Toxicomanie aux opiacés: étude au moyen de la P300 du sevrage et du traitement de substitution par la méthadone.

The aim of this study was to assess cognitive functions in two clinical conditions, namely during heroin detoxification and during substitution treatment by methadone. Two groups of chronic heroin user inpatients, meeting DSM-III-R criteria for concurrent opiate dependence, were tested using an auditory oddball paradigm of P300. The first group (four women and six men) were drug-free and the second (five women, ten men) received methadone treatment. Patients were also compared to a control group of non-dependent healthy subjects (five women, nine men). The patients were recorded 6-10 days after the beginning of either detoxification or methadone treatment. There were significant P300 alterations in the two patient groups, with amplitude decrease and latency increase, at a time when self-reported signs of withdrawal were absent or minimal. Paradoxically, the reaction time was accelerated in the two groups of patients, who also showed increased discrimination errors. These abnormalities were found with a lesser degree in the methadone-treated group than in detoxification patients.