Neurological Soft Signs: A Further Step in the Diagnosis of Bipolar-I Disorder

Article excerpt

Objectives: To study the prevalence and demographic characteristics of Neurological Soft Signs (NSS) among the patients with Bipolar Mood Disorder-I (BID).

Method: In a cross- sectional descriptive-analytic study we studied 20 patients with BID with BID with 20 healthy individuals. We used DSM-IV and Young Mania Rating Scale (MRS) for diagnosing and rating the patients with BID, Neurological Evaluation Scale along for assessment of NSS.

Control subjects who were matched on age and sex were selected; other confounding factors such as age at the onset, severity and duration of the disease were also considered and analyzed to find any possible correlation with NSS.

Results: Total NSS scores were significantly higher in the patients' group (PV<0.0001). The most significant difference in NSS subscales was detected in the Sequencing of Complex Motor Acts (PV<0.0001). No significant correlation was found between NSS scores and age at the onset of the disease, severity and duration of the disease and medication.

Conclusion: This study may emphasize the role of NSS as a sign of organic brain disorder which may be present independent of medication effects in the patients with BID; however, further studies may be able to extend our findings to explore the etiology and pathogenesis of BID.

Keywords:

Bipolar- I Disorder, Neurological Soft Signs, Neurological examination

Iran J Psychiatry 2009; 4:7-12

A long time has passed since the term "Neurological Soft Signs (NSS)" has entered the medical literature" by Loretta Bender in 1940 (1). Afterwards, other studies have been done on NSS in other psychiatric disorders such as first episode psychosis, and schizophrenia (2). It has been shown that the prevalence of NSS is higher in first episode psychosis and in medication naive schizophrenia patients (2, 3). However, less attention has been paid to mood disorders.

It is believed that Neurological Soft Signs are reflections of functional disorders in the selective parts of the brain; and the previous belief that these signs only indicate diffuse brain dysfunction do not seem to be correct (4). Recent studies have supported the idea that NSS may be related to a specific deficit in the function or anatomical regions of the brain (5, 6). This is why scientists assume that these signs can be used as a bridge to connect neurology and psychiatry. More than half a century after NSS's first definition, at this time, the role of NSS is more important in elucidating the etiology (7), prognosis (8), differential diagnosis (6, 7) and even prediction of the response to treatment (9, 10) in different psychiatric disorders.

Biological factors such as neurochemical and hormonal imbalance, genetic factors and psycho-social mechanisms so far have been known as the etiology of BID. Furthermore, neuroanatomical and neurophysiological etiological factors refer to the localization of the specific regions in the brain (11). It has been found that BID was related to anatomic abnormalities in the medial temporal lobe, especially in amygdale, prefrontal cortex and cerebellum (12).

Instead of relying on advanced technology which demands exorbitant expenses and highly-trained staff, we focused on a feasible clinical method by comparing NSS in BID patients and controls in order to assess our main hypothesis which implies that NSS are more prominent in the patients with BID than normal subjects. Other adjunct goals of this study were to evaluate the possible correlation between characteristics of the disease including severity, age at the onset and duration of the disease, with total NSS score. The effect of medications used regularly to control the disease on the NSS was also assessed as a probable confounding factor.

Materials and Method

Twenty patients diagnosed with BID by two psychiatrists (convenience sampling) according to DSM-IV criteria were selected from those admitted to Roozbeh Hospital (13). …