Dr Cummings Comprehensive 

These include:

- Chouinard et al's Extrapyramidal Rating Scale (Chouinard et al, 1980),

- Targeting Abnormal Kinetic Effects (TAKE) scale (Wojcik et al, 1980),

-Extrapyramidal Symptoms Scale (Adler et al, 1989)

-Neurological Rating Scale for Extrapyramidal Effects (Simpson-Angus scale; Simpson & Angus, 1970).

The scales vary in the emphasis they place on the different features of drug-induced parkinsonism. The TAKE scale, for example, places more emphasis on akinesia and bradykinesia, while the Simpson-Angus scale places the majority of emphasis on rigidity.

The Simpson-Angus scale was devised to measure drug-induced parkinsonism, providing standardised ratings for rigidity, tremor and salivation. The scale is entirely sign led. It contains 10 items, each rated on a 5-point scale (0-4), with descriptive anchors for each point and a clearly described examination procedure for each item. Six of the 10 items rate rigidity: arm dropping, shoulder shaking, elbow rigidity, wrist rigidity, leg pendulousness and neck rigidity. There is a single item for gait, which is the only measure for bradykinesia, and is in fact a compound item incorporating gait, posture and loss of arm swing. The other three items measure tremor, glabellar tap and salivation.

Perhaps the main criticism of the scale is that it is not particularly comprehensive in assessing the full range of symptoms, overemphasising rigidity. Some authors view bradykinesia as the main feature of the condition and criticise the scale for only indirectly measuring this through the item on gait (Owens, 1999).

The examination method for assessing neck rigidity recommended in the Simpson-Angus scale is flawed both in terms of its utility in rating this item and of disrupting professional rapport with the patient. The procedure is that the patient Òlies on a well padded table (if such a thing is to hand) and his head is raised by the examiner's hand and then allowed to drop". In normal subjects the head will fall onto the table, whereas in mild parkinsonism the movement is delayed and in severe cases it is absent.

The Simpson-Angus scale has only one item for tremor, relating to tremor of the fingers and arm or whole body tremor, but no items relating to titubation or tongue tremor. There is no mechanism for differentiating between mild Parkinsonian tremor and tremor with other causes (such as anxiety, lithium or benign essential tremor).

Salivation is rated in a single item according to observation of pooling of saliva in the mouth, difficulty with speaking because of excess salivation or actual drooling. The mechanism of excess salivation in drug-induced parkinsonism is unknown, but one explanation is that saliva accumulates because the patient is swallowing less frequently. Excess salivation may occur for reasons other than parkinsonism. For example, it occurs in about a third of patients taking clozapine.

The conventional scoring system for the Simpson-Angus scale is to calculate a global score by summing the individual item scores and then dividing by the total number of items. Simpson and Angus considered that a final score of up to 0.3 was Òwithin the normal range". .

The TAKE scale rates many manifestations of bradykinesia, but few manifestations of rigidity. Bradykinesia is characterised by features such as paucity of gesture, a mask-like facies and slow monotonous speech. These features may be mistaken for retarded, or ‘akinetic’, depression. There is also a potential overlap between these symptoms and negative features of schizophrenia such as affective flattening, poverty of speech and lack of drive (Barnes & McPhillips, 1995). Whether current assessment scales for negative features allow differentiation of affective flattening from these more subjective features of drug-induced parkinsonism is in some doubt. It may be that the concentration on more objective features, such as rigidity in the Simpson-Angus scale, confers an advantage of lack of measurement redundancy.