OS_16. Abnormal Psychology

Saturday, October 01st,   2011 [10:50 - 11:50]

TALKS

OS_16.1 - Impaired implicit sequence learning under dual task conditions in freezing of gait patients

Vandenbossche, J. ^{1, 2} , Deroost, N. ¹ , Soetens, E. ¹ , Coomans, D. ¹ , Nieuwboer, A. ³ & Kerckhofs, E. ^{1, 2}

1 Cognitive Psychology, Vrije Universiteit Brussel, Brussels, Belgium
2 Neurological Rehabilitation, Vrije Universiteit Brussel, Brussels, Belgium
3 Rehabilitation Sciences, Katholieke Universiteit Leuven, Leuven, Belgium

We examined whether implicit sequence learning, with or without additional working memory load, is impaired in patients with freezing of gait (FOG), a major disturbing symptom in Parkinson’s disease (PD). Fourteen freezers, 14 non-freezers and 14 matched healthy controls performed a serial reaction time (SRT) task with a deterministic stimulus sequence under single (SRT-ST) and dual task (SRT-DT) conditions. The increase in reaction times for random as compared to sequenced trials was used as a measure of implicit sequence learning. Scales for Outcomes in PD-cognition (SCOPA-COG) and tests for cognitive flexibility and set shifting were used as neuropsychological measures of cognitive functioning. Only non-freezers and healthy controls showed significant implicit sequence learning effects, whereas freezers only demonstrated a tendency to learn sequence-specific information in the SRT-ST task. In the SRT-DT task, no sequence learning occurred in FOG. Set-shifting and cognitive flexibility did not correlate with SRT learning, however, scores on the revised Freezing Of Gait Questionnaire (NFOGQ), assessing the severity of FOG, correlated positively with SRT-DT task performance. These results show that implicit sequence learning under dual task conditions is impaired in freezers, and provide more insight into the mechanisms of compensation for deficient motor automaticity in FOG.

OS_16.2 - A critical appraisal of neglect and pseudoneglect for the mental number line

Priftis, K. ^{1, 2} , Umiltà, C. ¹ & Zorzi, M. ¹

1 Department of General Psychology, University of Padova, Italy
2 IRCCS, San Camillo Hospital, Lido-Venice, Italy

We aim to provide a critical overview of the evidence that links spatial representation
with the representation of number magnitude. This aim is achieved by reviewing critically the literature concerning the mental number
interval bisection and related tasks in patients with left hemispatial neglect and in healthy participants (pseudoneglect). Finally, we shall consider some alternative, non-spatial explanations of the reviewed effects. We conclude that evidence from neglect and pseudoneglect might constitute the strongest evidence in favour of a left-to-right oriented mental number line for representing number magnitude in the human brain.

OS_16.3 - The visuospatial imagery of sequence-space synaesthesia

Price, M.

University of Bergen, Psychology Faculty

A large minority of people report experiencing certain ordinal sequences such as numbers or calendar units as arranged in precise visuospatial layouts in imaginal or peripersonal space. The phenomenon has been described since the time of Galton at the end of the 19th century but recent years have seen a steady increase in experimental studies of these experiences. Most of this research has considered these so-called spatial forms as a variety of synaesthesia (sequence-space synaesthesia), noting many aspects of the experiences that conform to standard criteria of synaesthesia. However there are several respects in which spatial forms might be better thought of as overlearned visuospatial images. I will review some of these aspects of spatial forms, drawing on both descriptive self-report data and behavioural data, and emphasizing the continuity of the phenomenon with standard intentional thought imagery. Topics that I will consider include the association between these experiences and various categories of visuospatial imagery, the manner in which spatial forms do or do not qualify as automatically mediated, and the extent to which the apparent idiosyncrasies of spatial forms are rational attempts to depict sequence information in a spatial manner.