Thesis (PhD)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Background
The changes in cognition, brain structure, and neurological soft signs which are
characteristic of schizophrenia appear to have been present before the onset of the
phenotype. They therefore find relevance as potential vulnerability markers of the disease.
Neurological soft signs are of particular interest because they can be elicited quickly,
reliably and cheaply. They have also been touted as markers of certain characteristics of
schizophrenia. The most convincing evidence for these assertions come from prospective
longitudinal studies of first episode, medication naive patients with schizophrenia. Most of
these studies have been based on wholly Caucasian or mixed samples of Caucasians and
other races. The present study provides important reference data on the nature of
neurological soft signs in indigenous African subjects and clarifies the trait or state
marking signs in this population. Method
A total of 84 patients with first episode, schizophrenia, schizo-affective disorder, or
schizophreniform disorder meeting criteria in the fourth edition of the Diagnostic and
Statistical Manual for Mental Disorders were consecutively recruited. Information on
demographic characteristics, personal medical and psychiatric history, as well as family
history was obtained at baseline. Neurological assessment was based on the 26 item
Neurological Evaluation Scale. An exploratory factor analysis of the items in the scale was
conducted using the baseline measurements. The derived sub-sets of neurological soft signs were then followed up longitudinally and in parallel with the ‘functional categories’
of the signs. The study describes the profile of neurological soft signs across the one year
course of schizophrenia, as well as their relationship with a wide range of clinical and
outcome variables. The severity of the baseline psychopathology was evaluated by
administering the Positive and Negative Syndrome Scale. The overall clinical status was
assessed using Clinical Global Impression. Additional assessments included the Calvary
Depression Scale for Schizophrenia, Birchwood Insight Scale, Social and Occupational
Functioning Assessment Scale, and the World Health Organisation Quality of Life Scale
(WHO QoL-BREF). Pre-morbid adjustment was assessed using the Pre morbid
Adjustment Scale, while extra-pyramidal effect of antipsychotics was assessed using the
Extra-pyramidal Symptoms Rating Scale. Assessments were repeated at three monthly
intervals for the full 12 months. Results
Neurological soft signs were present in 96.4% of the sample at baseline. The signs loaded
into a four factor structure: perceptual and motor sequencing (audio-visual integration,
fist-edge palm, rhythm tapping, extinction, and right-left confusion), eye movements
(synkinesis, convergence, and gaze impersistence), motor co-ordination and
graphaesthesia (tandem walk, adventitious flow, and graphaesthesia), as well as
stegreognosis. The scores for the perceptual and motor sequencing factor, as well as those
for the sequencing of complex motor acts ‘functional category’ were stable across three
measurements over 12 months (F=1.26, p=0.287, and F=1.87, p=0.158 respectively). The
sequencing of complex motor act signs was not significantly correlated with the clinical
and outcome characteristics of schizophrenia. However, other signs, as well as the NES total score were significantly correlated with more severe negative and disorganized
psychopathology, as well as poorer outcome in terms of functioning and quality of life.
Conclusion
Neurological soft signs were present at a high frequency at baseline. A preponderance of
the signs was associated with a more severe negative and disorganization
psychopathology, as well as a poorer functional outcome and quality of life. Abnormal
sequencing of complex motor act signs, and signs of abnormal cognitive processing of
perceptual stimuli where resistant to changes in psychopathology, and thus may represent
viable trait markers for schizophrenia in this cohort.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/86327 |
| Date | 04 1900 |
| Creators | Ojagbemi, Abel Akinsola |
| Contributors | Gureje, Oye, Emsley, Robin, Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Psychiatry. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | 291 p. |
| Rights | Stellenbosch University |
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